JP3439631B2 - High frequency switch - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency switch used in a semiconductor integrated circuit, and more particularly to a high frequency switch for switching a signal path in a transmission / reception circuit or the like.

[0002]

2. Description of the Related Art Conventionally, as a high frequency switch, there is one using a variable resistance characteristic of a diode as shown in FIG. This high frequency switch includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception terminal Rx to which a reception circuit (not shown) is connected. And switching the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna.
The cathode of the first diode D1 is connected to the transmission terminal Tx via a capacitor C61. The cathode of the first diode D1 is grounded via the first transmission line 61 that functions as a choke coil. And the first
The anode of the diode D1 is connected to the antenna terminal ANT via the capacitor C62. Furthermore, the first
A second transmission line 62 acting as a choke coil and a capacitor C63 are connected in series between the anode of the diode D1 and the ground. The second transmission line 62
A control terminal CT60 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at a connection point between the capacitor C63 and the capacitor C63. Also,
One end of the third transmission line 63 is connected to the anode of the first diode D1. The receiving terminal Rx is connected to the other end of the third transmission circuit 63 via a capacitor C64. Also, the third transmission circuit 63 and the capacitor C64
The anode of the second diode D2 is connected to the connection point between and, and the cathode of the second diode D2 is grounded.

When transmitting using the high frequency switch, a positive voltage is applied to the control terminal CT60. At this time, the direct current component is cut by the capacitors C61 to C64, and the voltage applied to the control terminal CT60 is applied only to the circuit including the diode D1 and the second diode D2. The voltage applied to the control terminal CT60 turns on the first diode D1 and the second diode D2. By turning on the first diode D1, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal ANT, and the transmission signal is transmitted from the antenna. On the other hand, the second transmission line 63 resonates when the transmitting terminal Rx side is grounded by the second diode D2, and its impedance becomes infinite. Therefore, the transmitting signal from the transmitting terminal Tx is received by the receiving terminal Rx. Not transmitted to.

On the other hand, during reception, the control terminal CT
By not applying a voltage to 60, the first diode D1 and the second diode D2 are turned off,
The reception signal from the antenna terminal ANT is transmitted to the reception terminal Rx via the second transmission line 63 and the capacitor C64.
It is not transmitted to the transmission terminal Tx.

[0005]

By the way, the diodes D1 and D2 used in the high frequency switch have the characteristics of high frequency operating resistance with respect to the consumption current shown in FIG. Note that FIG. 10 shows characteristics of a diode using a pn heterojunction formed on a gallium arsenide substrate. As shown in FIG. 10, the diodes D1 and D2 have a characteristic that the resistance value decreases when a large amount of current flows, and this characteristic is used for the switch. However, there is a problem that the resistance value is about 5Ω even when a current of 10 mA is applied, and the insertion loss is large when the diode is in the ON state. Also, in order to reduce the current consumption, when trying to operate at 1 mA or less,
Since the resistance value is 25Ω or more, it is impossible to obtain a high frequency switch with a small insertion loss.

Therefore, an object of the present invention is to provide a high-frequency switch with low current consumption and low insertion loss.

[0007]

In order to achieve the above object, a high frequency switch according to a first aspect of the present invention comprises a bipolar transistor whose base is grounded through a resistor and a collector and an emitter of the bipolar transistor connected in series. A variable capacitance circuit having an inductor and a capacitor connected to each other and having a collector and an emitter of the bipolar transistor as terminals, and a collector of the bipolar transistor.
-By applying a reverse bias to the base-to-base diode,
Turns off the polar transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In addition, the above bipolar transistor is turned off in terms of direct current.
It is characterized in that it is turned on in the state and in terms of alternating current .

According to the high frequency switch of claim 1,
For example, when the bipolar transistor of the variable capacitance circuit is an NPN type, if the emitter potential of the bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, the collector-base diode and the emitter-base diode are reverse biased. Is applied. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than in the forward bias state,
It is turned off both in terms of direct current and in terms of high frequency. At this time,
By setting the inductance of the inductor so that the collector-emitter capacitor of the bipolar transistor and the inductor resonate in parallel, isolation in the off state is further improved. On the other hand, when the collector potential of the bipolar transistor is set lower than the base potential, a forward bias is applied to the collector-base diode. Then, when the forward bias current tries to increase, the base potential decreases due to the resistance connected between the base and ground, the forward bias of the collector-base diode decreases, and the low current is maintained. To be done. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency.

As described above, by constructing the high frequency switch by using the variable capacitance circuit having the ON / OFF characteristic in the high frequency band, the current consumption can be reduced. Further, this variable capacitance circuit can have a smaller resistance value and a smaller insertion loss than those using a variable resistance characteristic of a diode.

A high frequency switch according to a second aspect of the present invention is a high frequency switch which is connected to a transmission circuit, a reception circuit and an antenna and which switches connection between the transmission circuit and the antenna and connection between the reception circuit and the antenna. A first bipolar transistor having an emitter connected to the transmitter circuit side, a collector connected to the antenna side, and a base grounded via a first resistor; and a first bipolar transistor of the first bipolar transistor. A first inductor and a first capacitor connected in series between a collector and an emitter, a transmission line connected between the antenna and the receiving circuit, and a collector connected to the receiving circuit side. A second bipolar transistor having a grounded via a second resistor and a grounded emitter, and the second bipolar transistor. Collector - a second inductor and a second capacitor connected in series between the emitter, the first, collection of the second bipolar transistor
Reverse bias is applied to the diode between the
The first and second bipolar transistors are DC and AC
While it is in the off state, it is forward between the collector and the base.
By applying a forward bias, the first and second bipolar transistors
The transistor is off for DC and on for AC.
It is characterized in that a state.

According to the high frequency switch of claim 2,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potentials of the first and second bipolar transistors are made lower than the base potential, a forward bias is applied to the collector-base diode. Then, when the forward bias current tries to increase, the base potential is lowered by the resistance connected between the base and the ground, the forward bias of the collector-base diode is reduced, and the low current is maintained. .. In this case, the number of charges in the diode is higher than in the reverse bias state,
It is kept almost constant, and is turned off in terms of direct current and turned on in terms of high frequency. By doing so, while the transmission signal from the transmission circuit is transmitted to the antenna side, the transmission line resonates by grounding the reception circuit side,
The transmitted signal is not transmitted to the receiving circuit side because its impedance becomes infinite.

On the other hand, when the emitter potential of the first and second bipolar transistors is set to zero or a positive potential and the collector potential is higher than the emitter potential, reverse bias is applied to the collector-base diode and the emitter-base diode. It In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit. At this time, by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in series, isolation between the antenna side and the transmission circuit side is obtained. Will be improved.

As described above, by constructing the high frequency switch by using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

A high frequency switch according to a third aspect of the invention is a high frequency switch which is connected to a transmission circuit, a reception circuit and an antenna and which switches connection between the transmission circuit and the antenna and connection between the reception circuit and the antenna. A first bipolar transistor having a collector connected to the transmission circuit side, an emitter connected to the antenna side, and a base grounded via a first resistor; A first inductor and a first capacitor connected in series between a collector and an emitter, a collector connected to the receiving circuit side, an emitter connected to the antenna side, and a base grounded via a second resistor. Second bipolar transistor and a second bipolar transistor connected in series between the collector and the emitter of the second bipolar transistor. A of the inductor and the second capacitor, the first, second bipolar transistor
Reverse bias is applied to the collector-base diode of
The above first and second bipolar transistors are direct current type
The above-mentioned collector-base while being turned off in alternating current
A forward bias is applied between the first and second bipolar plates.
The transistor is off for DC and for AC
Is characterized by being turned on .

According to the high frequency switch of the third aspect,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potential of the first bipolar transistor is lower than the base potential, a forward bias is applied to the collector-base diode. Then, as the forward bias current increases, the base
-The base potential drops due to the resistance connected between ground,
The forward bias of the collector-base diode is reduced in magnitude and low current is maintained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the second bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the transmission signal from the transmission circuit is transmitted to the antenna side, while the transmission line resonates when the reception circuit side is grounded and its impedance becomes infinite, so the transmission signal is received. Not transmitted to the circuit side. At this time, by setting the inductance of the second inductor so that the collector-emitter capacitor of the second bipolar transistor and the second inductor resonate in parallel, isolation between the antenna side and the receiving circuit side is set. Will be improved.

On the other hand, if the collector potential of the second bipolar transistor is set lower than the base potential, the collector
-Forward bias is applied to the base-to-base diode.
When the forward bias current is increased, the base potential is lowered due to the resistor connected between the base and ground, the forward bias of the collector-base diode is reduced, and the low current is reduced. Is retained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the first bipolar transistor is zero or positive and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit.
At this time, by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in parallel, isolation between the antenna side and the transmission circuit side is obtained. Will be improved.

As described above, by constructing the high frequency switch using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

A high frequency switch according to a fourth aspect of the present invention includes a bipolar transistor whose base is grounded through a resistor, and an inductor whose one end is connected to a collector or an emitter of the bipolar transistor. The collector or the collector of the bipolar transistor is provided with a variable capacitance circuit having the emitter or collector of
-By applying a reverse bias to the base-to-base diode,
Turns off the polar transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In addition, the above bipolar transistor is turned off in terms of direct current.
It is characterized in that it is turned on in the state and in terms of alternating current .

According to the high frequency switch of the fourth aspect,
For example, when the bipolar transistor of the variable capacitance circuit is an NPN type, if the emitter potential of the bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, the collector-base diode and the emitter-base diode are reverse biased. Is applied. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state described later, and the diode is turned off both in terms of direct current and high frequency. On the other hand, when the collector potential of the bipolar transistor is set lower than the base potential, a forward bias is applied to the collector-base diode. Then, when the forward bias current tries to increase, the base potential is lowered by the resistance connected between the base and the ground, the forward bias of the collector-base diode is reduced, and the low current is maintained. .. In this case, the number of charges in the diode is larger than that in the above-mentioned bias state and is kept almost constant, and the state is off in terms of direct current and on in terms of high frequency. At this time, the insertion loss is particularly reduced by setting the inductance of the inductor such that the collector-emitter capacitor of the bipolar transistor and the inductor resonate in series.

As described above, by constructing the high frequency switch by using the variable capacitance circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, this variable capacitance circuit can have a smaller resistance value and a smaller insertion loss than those using a variable resistance characteristic of a diode.

Further, the high frequency switch according to claim 5 is a high frequency switch which is connected to a transmission circuit, a reception circuit and an antenna and which switches connection between the transmission circuit and the antenna and connection between the reception circuit and the antenna. A first bipolar transistor whose emitter is connected to the transmitter circuit side and whose base is grounded via a first resistor; and one end of which is connected to the collector of the first bipolar transistor and whose other end is A first inductor connected to the antenna side, a transmission line connected between the antenna and the receiving circuit, and a second inductor having one end connected to the receiving circuit side of the transmission line. , A second bipolar transistor having a collector connected to the other end of the second inductor, a base grounded through a second resistor, and an emitter grounded. And a register, and the first and second
Collector-base diode of a bipolar transistor
Applying a reverse bias to the battery,
To turn off the transistor from both DC and AC
On the other hand, apply a forward bias between the collector and the base.
The above-mentioned first and second bipolar transistors are set to direct current.
Is characterized by being turned off and turned on in terms of alternating current .

According to the high frequency switch of the fifth aspect,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potentials of the first and second bipolar transistors are made lower than the base potential, a forward bias is applied to the collector-base diode. Then, when the forward bias current tries to increase, the base potential is lowered by the resistance connected between the base and the ground, the forward bias of the collector-base diode is reduced, and the low current is maintained. .. In this case, the number of charges in the diode is higher than in the reverse bias state,
It is kept almost constant, and is turned off in terms of direct current and turned on in terms of high frequency. By doing so, while the transmission signal from the transmission circuit is transmitted to the antenna side, the transmission line resonates by grounding the reception circuit side,
The transmitted signal is not transmitted to the receiving circuit side because its impedance becomes infinite. At this time, the insertion loss is particularly reduced by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in series.

On the other hand, when the emitter potential of the first and second bipolar transistors is set to zero or a positive potential and the collector potential is higher than the emitter potential, reverse bias is applied to the collector-base diode and the emitter-base diode. It In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit.

As described above, by constructing the high frequency switch by using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

The high frequency switch according to claim 6 is a high frequency switch which is connected to a transmitting circuit, a receiving circuit and an antenna and which switches the connection between the transmitting circuit and the antenna and the connection between the receiving circuit and the antenna. A first inductor whose one end is connected to the transmission circuit side, the other end of the first inductor is connected to the collector, the emitter is connected to the antenna side, and the base is connected via the first resistor. A grounded first bipolar transistor, a second bipolar transistor whose emitter is connected to the antenna side and whose base is connected via a second resistor, and one end of which is connected to the connector of the second bipolar transistor. is connected, the other end and a second inductor connected to the receiving circuit side, the first, second bus
Ipolar transistor collector-base diode
Applying a reverse bias to the first and second bipolar transistors
While turning off the transistor DC and AC,
Applying a forward bias between the collector and base above
Note that the first and second bipolar transistors are turned off in terms of direct current.
It is characterized in that it is in the off state and is in the on state in terms of alternating current .

According to the high frequency switch of the sixth aspect,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potential of the first bipolar transistor is lower than the base potential, a forward bias is applied to the collector-base diode. Then, as the forward bias current increases, the base
-The base potential drops due to the resistance connected between ground,
The forward bias of the collector-base diode is reduced in magnitude and low current is maintained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the second bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the transmission signal from the transmission circuit is transmitted to the antenna side, while the transmission line resonates when the reception circuit side is grounded and its impedance becomes infinite, so the transmission signal is received. Not transmitted to the circuit side. At this time, the insertion loss is particularly reduced by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in series.

On the other hand, if the collector potential of the second bipolar transistor is set lower than the base potential, the collector
-Forward bias is applied to the base-to-base diode.
When the forward bias current is increased, the base potential is lowered due to the resistor connected between the base and ground, the forward bias of the collector-base diode is reduced, and the low current is reduced. Is retained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the first bipolar transistor is zero or positive and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit.
At this time, the insertion loss is particularly reduced by setting the inductance of the second inductor so that the collector-emitter capacitor of the second bipolar transistor and the second inductor resonate in series.

As described above, by constructing the high frequency switch by using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

A high frequency switch according to a seventh aspect of the present invention includes a bipolar transistor whose base is grounded via a resistor, a first inductor and a first capacitor which are connected in series between a collector and an emitter of the bipolar transistor. A second inductor having one end connected to the collector or emitter of the bipolar transistor, the variable capacitance having the emitter or collector of the bipolar transistor as a terminal and the other end of the second inductor as a terminal The circuit is equipped with the bipolar transistor
Reverse bias on diode between collector and base of transistor
Is applied to the bipolar transistor,
While it is turned off, it is between the collector and the base.
Forward bias applied to the bipolar transistor
Is turned off in terms of direct current and turned on in terms of alternating current .

According to the high frequency switch of claim 7,
For example, when the bipolar transistor of the variable capacitance circuit is an NPN type, if the emitter potential of the bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, the collector-base diode and the emitter-base diode are reverse biased. Is applied. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than in the forward bias state,
It is turned off both in terms of direct current and in terms of high frequency. At this time,
By setting the inductance of the inductor so that the collector-emitter capacitor of the bipolar transistor and the inductor resonate in parallel, isolation in the off state is further improved.

On the other hand, when the collector potential of the bipolar transistor is set lower than the base potential, a forward bias is applied to the collector-base diode. Then, as the forward bias current increases, the base
-The base potential drops due to the resistance connected between ground,
The forward bias of the collector-base diode is reduced in magnitude and low current is maintained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. At this time, the collector of the bipolar transistor
-Insertion loss is particularly reduced by setting the inductor inductance so that the emitter-emitter capacitor and the inductor resonate in series.

As described above, by constructing the high frequency switch by using the variable capacitance circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, this variable capacitance circuit can have a smaller resistance value and a smaller insertion loss than those using a variable resistance characteristic of a diode.

Further, the high-frequency switch according to claim 8, the transmission circuit, connected to the receiving circuit and the antenna, high frequency for switching the connection and the connection between the receiving circuit and the antenna of the transmitting circuit and the antenna A switch, a first bipolar transistor whose emitter is connected to the transmitter circuit side and whose base is grounded via a first resistor, and a collector-emitter of the first bipolar transistor in series A first inductor and a first capacitor connected to each other, a second inductor having one end connected to the collector of the first bipolar transistor and the other end connected to the antenna side, the antenna, and the receiving circuit. A transmission line connected to the transmission line, a third inductor having one end connected to the reception circuit side of the transmission line, and the third inductor. Kuta other end collector connected to the base is grounded through a second resistor, a second bipolar transistor whose emitter is grounded, the second
The collector of the transistor - and a fourth inductor connected in series between the emitters second capacitor, the
Between collector and base of first and second bipolar transistors
Applying reverse bias to the diode, the first and second bipolar
The off-state transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In terms of direct current, the first and second bipolar transistors are
It is characterized in that it is turned off and turned on in terms of alternating current .

According to the high frequency switch of claim 8,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potentials of the first and second bipolar transistors are made lower than the base potential, a forward bias is applied to the collector-base diode. Then, when the forward bias current tries to increase, the base potential is lowered by the resistance connected between the base and the ground, the forward bias of the collector-base diode is reduced, and the low current is maintained. .. In this case, the number of charges in the diode is higher than in the reverse bias state,
It is kept almost constant, and is turned off in terms of direct current and turned on in terms of high frequency. By doing so, while the transmission signal from the transmission circuit is transmitted to the antenna side, the transmission line resonates by grounding the reception circuit side,
The transmitted signal is not transmitted to the receiving circuit side because its impedance becomes infinite. At this time, the insertion loss is particularly reduced by setting the inductance of the second inductor so that the collector-emitter capacitor of the first bipolar transistor and the second inductor resonate in series.

On the other hand, when the emitter potential of the first and second bipolar transistors is set to zero or a positive potential and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. It In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit. At this time, by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in parallel, isolation between the antenna side and the transmission circuit side is obtained. Will be improved.

As described above, by constructing the high frequency switch by using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

The high frequency switch according to claim 9 is a high frequency switch which is connected to a transmitting circuit, a receiving circuit and an antenna and which switches the connection between the transmitting circuit and the antenna and the connection between the receiving circuit and the antenna. A first inductor whose one end is connected to the transmission circuit side, the other end of the first inductor is connected to the collector, the emitter is connected to the antenna side, and the base is the first resistor. A first bipolar transistor which is grounded via a second inductor, a second inductor and a first capacitor which are connected in series between a collector and an emitter of the first bipolar transistor, and an emitter which is connected to the antenna side, A second bipolar transistor whose base is grounded via a second resistor, and a collector-to-air terminal of the second bipolar transistor. Tsu third connected in series between the motor
The inductor and the second capacitor, the one end to the collector of the second bipolar transistor is connected, and a fourth inductor whose other end is connected to the receiving circuit side, the first, second bipolar Transistor collect
Reverse bias is applied to the diode between the
The first and second bipolar transistors are DC and AC
While it is in the off state, it is forward between the collector and the base.
By applying a forward bias, the first and second bipolar transistors
The transistor is off for DC and on for AC.
It is characterized in that a state.

According to the high frequency switch of the ninth aspect,
For example, if the first and second bipolar transistors are N
In the case of the PN type, when the collector potential of the first bipolar transistor is lower than the base potential, a forward bias is applied to the collector-base diode. Then, as the forward bias current increases, the base
-The base potential drops due to the resistance connected between ground,
The forward bias of the collector-base diode is reduced in magnitude and low current is maintained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the second bipolar transistor is set to zero or a positive potential and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the transmission signal from the transmission circuit is transmitted to the antenna side, while the transmission line resonates when the reception circuit side is grounded and its impedance becomes infinite, so the transmission signal is received. Not transmitted to the circuit side. At this time, the insertion loss is particularly reduced by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in series.
Also, the collector of the second bipolar transistor
By setting the inductance of the second inductor so that the inter-emitter capacitor and the second inductor resonate in parallel, the isolation between the antenna side and the receiving circuit side is further improved.

On the other hand, if the collector potential of the second bipolar transistor is set lower than the base potential, the collector
-Forward bias is applied to the base-to-base diode.
When the forward bias current is increased, the base potential is lowered due to the resistor connected between the base and ground, the forward bias of the collector-base diode is reduced, and the low current is reduced. Is retained. In this case, the number of charges in the diode is larger than that in the reverse bias state and is kept substantially constant, and the state is off in terms of direct current and on in terms of high frequency. On the other hand, when the emitter potential of the first bipolar transistor is zero or positive and the collector potential is higher than the emitter potential, a reverse bias is applied to the collector-base diode and the emitter-base diode. In this case, the current is about the leakage current of the diode, the number of charges in the diode is smaller than that in the forward bias state, and the diode is turned off both in terms of direct current and high frequency. By doing so, the reception signal from the antenna is transmitted to the reception circuit, but is not transmitted to the transmission circuit.
At this time, by setting the inductance of the first inductor so that the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in parallel, isolation between the antenna side and the transmission circuit side is obtained. Will be improved. Further, the insertion loss is particularly reduced by setting the inductance of the second inductor so that the collector-emitter capacitor of the second bipolar transistor and the second inductor resonate in series.

As described above, by constructing the high frequency switch using the circuit having the on / off characteristic in the high frequency band, the current consumption can be reduced. Further, since this high frequency switch utilizes the variable capacitance characteristic having a small resistance value, the insertion loss can be reduced.

BEST MODE FOR CARRYING OUT THE INVENTION The high frequency switch of the present invention will be described in detail below with reference to the embodiments shown in the drawings.

(First Embodiment) FIG. 1 is a circuit diagram of a high frequency switch according to a first embodiment of the present invention. As shown in FIG. 1, this high frequency switch SW
1 is an antenna terminal A to which an antenna (not shown) is connected
A transmission terminal Tx to which NT and a transmission circuit (not shown) are connected
And a receiving terminal Rx to which a receiving circuit (not shown) is connected. The capacitor C1 is connected to the transmission terminal Tx.
The emitter of the first bipolar transistor Q1 is connected via. The first bipolar transistor Q
The emitter of 1 is grounded via the first transmission line 1 acting as a choke coil, and the base of the first bipolar transistor Q1 is grounded via the first resistor R1. A first inductor L1 and a first capacitor C2 are connected in series from the collector side between the collector and emitter of the first bipolar transistor Q1. The collector of the first bipolar transistor Q1 is connected to the antenna terminal ANT via the capacitor C3. Further, a second transmission line 2 acting as a choke coil and a capacitor C4 are serially connected in series from the collector side between the collector of the first bipolar transistor Q1 and the ground. A control terminal CT1 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at a connection point between the second transmission line 2 and the capacitor C4.

Further, one end of the third transmission line 3 is connected to the collector of the first bipolar transistor Q1 and the other end of the third transmission line 3 is connected to the receiving terminal Rx via the capacitor C6. There is. The third transmission line 3
The collector of the second bipolar transistor Q2 is connected to the connection point between the capacitor C6 and the capacitor C6. The base of the second bipolar transistor Q2 is grounded via the first resistor R2, and the emitter of the second bipolar transistor Q2 is grounded. Second above
A second inductor L2 and a second capacitor C5 are connected in series from the emitter side between the collector and the emitter of the bipolar transistor Q2.

In order to explain the operation of the high frequency switch SW1, a variable capacitance circuit 4 composed of a first bipolar transistor Q1, a first resistor R1, an inductor L1 and a first capacitor C2, and a second bipolar transistor. Attention is paid only to the variable capacitance circuit 5 composed of Q2, the first resistor R2, the inductor L2 and the second capacitor C5.

FIG. 2 shows the characteristics of the collector-emitter capacitance Ctr of the transistor Q1 (Q2) with respect to the collector-emitter voltage when the emitter of the first (second) bipolar transistor Q1 (Q2) is set to zero potential. Figure 3
Shows the characteristics of current consumption with respect to collector-emitter voltage. 2 and 3 show the characteristics when using a heterojunction bipolar transistor manufactured on a gallium arsenide substrate. By changing the value of the first resistor R1 (R2), optimum consumption current characteristics and Ctr characteristics with respect to the collector-emitter voltage can be obtained. Inductor L1 (L2) connected in series between the collector and emitter of the first (second) bipolar transistor Q1 (Q2)
When the in-da inductance Lp, and the angular frequency used omega, the capacitance value C of the variable capacitance circuit 4 (5) is expressed by the following equation.

[0045]

ΩC = ωCtr-1 / (ωLp) Therefore, with the minimum value of the collector-emitter capacitance Ctr as Cmin and the maximum value as Cmax, the capacitance Coff in the off state and the capacitance Coff in the on state of the variable capacitance circuit 4 (5) are set. Lp, Cmax and Cmin are determined so that the capacitance Con satisfies the following equation.

[0046]

[Equation 2] ωCoff = ωCmin−1 / (ωLp) = 0

ΩCon = ωCmax−1 / (ωLp) = ω (Cmax−Cmin) That is, the inductance Lp is determined so that parallel resonance is caused by the capacitance Cmin and the reactance Lp, and the capacitance Co
The capacitances Cmin and Cmax are determined so that n has a low insertion loss. In the case of the characteristics shown in FIGS. 2 and 3, when the resistance value Rbb of the first resistor R1 (R2) is 1000Ω, the capacitance Con (= Cmax-Cmin) of the variable capacitance circuit 4 (5) has a current of 0.8 m.
Below A, 5.8 pF is obtained. 5.8pF of this capacity Con
Is, for example, when the frequency used is 1.9 GHz, the insertion loss is 0.09 dB, which is the low insertion loss ON state.
It can be seen that on / off control is possible at a current of 0.8 mA or less.

When performing transmission using the high-frequency switch SW1 having the above structure, a negative voltage is applied to the control terminal CT1. At this time, the DC components are cut by the capacitors C1 to C6, and the voltage applied to the control terminal CT1 is applied only to the circuit including the first bipolar transistor Q1 and the second bipolar transistor Q2. The voltage applied to the control terminal CT1 turns on the first variable capacitance circuit 4 and the second variable capacitance circuit 5. When the first variable capacitance circuit 4 is turned on, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal ANT and the antenna terminal ANT.
A transmission signal is transmitted from the antenna via the. At this time, the second transmission line 3 resonates when the receiving terminal Rx side is grounded by the second variable capacitance circuit 5, and its impedance becomes infinite. Therefore, the transmission signal from the transmitting terminal Tx becomes It is not transmitted to the reception terminal Rx.

On the other hand, during reception, the control terminal CT
A positive voltage is applied to 1. At this time, since the first variable capacitance circuit 4 and the second variable capacitance circuit 5 are turned off, the reception signal from the antenna terminal ANT is transmitted to the reception terminal Rx while being transmitted to the transmission terminal Tx. Not done. At this time, the first bipolar transistor Q1
Since the collector-emitter capacitor of 1 and the first inductor L1 resonate in parallel, the isolation in the off state is further improved.

As described above, by using the variable capacitance circuits 4 and 5 having the ON / OFF characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

(Second Embodiment) FIG. 4 shows a high frequency switch SW2 according to a second embodiment of the present invention.
It is a circuit diagram of. The high frequency switch SW2 includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception circuit.
(Not shown) is connected to the receiving terminal Rx.
A first bipolar transistor Q11 is connected to the transmission terminal Tx.
Is connected via a capacitor C11. A first transmission line 1 acting as a choke coil is provided between the collector of the first bipolar transistor Q11 and the ground.
1 and the capacitor C12 are connected in series from the collector side. A first control terminal CT10 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at the connection point between the first transmission line 11 and the capacitor C12. The base of the first bipolar transistor Q11 is grounded via the first resistor R11. In addition, the first bipolar transistor Q
A first inductor L11 and a first capacitor C13 are connected in series between the collector and emitter of 11 in order from the emitter side. The emitter of the first bipolar transistor Q11 is connected to the antenna terminal ANT via the capacitor C14. Further, the collector of the first bipolar transistor Q11 is grounded via the second transmission line 12 that functions as a choke coil.

The emitter of the second bipolar transistor Q12 is connected to the emitter of the first bipolar transistor Q11. The base of the second bipolar transistor Q12 is grounded via the second resistor R12. A second inductor L12 and a second capacitor C15 are serially connected in series from the emitter side between the collector and the emitter of the second bipolar transistor Q12. The receiving terminal Rx is connected to the collector of the second bipolar transistor Q12 via a capacitor C17. Further, a third transmission line 13 acting as a choke coil and a capacitor C16 are connected in series in order from the collector side between the collector of the second bipolar transistor Q12 and the ground. A second control terminal CT11 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at the connection point between the third transmission line 13 and the capacitor C16.

The first bipolar transistor Q11,
The first variable capacitance circuit 14 is composed of the first resistor R11, the first inductor L11, and the first capacitor C13, and the second bipolar transistor Q12 and the second resistor R1 are also included.
The second variable capacitance circuit 15 is composed of the second inductor L12 and the second capacitor C15. The first variable capacitance circuit 14 and the second variable capacitance circuit 15 are
The on / off control operation is performed according to the same principle as the embodiment.

When transmission is performed using the high frequency switch SW2 having the above structure, a negative voltage is applied to the first control terminal CT10 and a positive voltage is applied to the second control terminal CT11. The direct current component is cut by the capacitors C11 to C17, and the voltage applied to the first control terminal CT10 and the second control terminal CT11 becomes the first voltage.
Of the bipolar transistor Q11 and the second bipolar transistor Q12. By the negative voltage applied to the first control terminal CT10, the first variable capacitance circuit 14 is turned on and the second variable capacitance circuit 14 is turned on.
Since the second variable capacitance circuit 15 is turned off by the negative voltage applied to the control terminal CT11 of, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal ANT and is transmitted from the antenna via the antenna terminal ANT. The transmission signal is transmitted and is not transmitted to the reception terminal Rx. At this time, the collector-emitter capacitor of the second bipolar transistor Q12 and the second inductor L12 resonate in parallel, so that the antenna terminal ANT and the receiving terminal Rx are connected.
The isolation with is improved.

On the other hand, during reception, a positive voltage is applied to the first control terminal CT10 and a negative voltage is applied to the second control terminal CT11. At this time, the first variable capacitance circuit 14 is turned off and the second variable capacitance circuit 15 is turned on according to the same principle as during transmission. Therefore, the reception signal from the antenna terminal ANT is transmitted to the reception terminal Rx and is not transmitted to the transmission terminal Tx. At this time, the collector of the first bipolar transistor Q11
-Since the inter-emitter capacitor and the first inductor L11 resonate in parallel, the isolation between the antenna terminal ANT and the transmission terminal Tx is further improved.

As described above, by using the variable capacitance circuits 14 and 15 having the ON / OFF characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

(Third Embodiment) FIG. 5 shows a high frequency switch SW3 according to a third embodiment of the present invention.
It is a circuit diagram of. The high frequency switch SW3 includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception circuit.
(Not shown) is connected to the receiving terminal Rx.
The first bipolar transistor Q21 is connected to the transmission terminal Tx.
Is connected via a capacitor C21. The emitter of the first bipolar transistor Q21 is grounded via the first transmission line 21 acting as a choke coil, and the base of the first bipolar transistor Q21 is grounded via the first resistor R21. . One end of the first inductor L21 is connected to the collector of the first bipolar transistor Q21. The other end of the first inductor L21 is connected to the antenna terminal AN via the capacitor C22.
It is connected to T. Further, a second transmission line 22 acting as a choke coil and a capacitor C23 are connected in series in order from the first inductor L21 side between the other end of the first inductor L21 and the ground. A control terminal CT20 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at a connection point between the second transmission line 22 and the capacitor C23.

Further, one end of the third transmission line 23 is connected to the connection point between the first inductor L21 and the capacitor C22. The other end of the third transmission line 23 is connected to the receiving terminal Rx via a capacitor C24. Then, one end of the second inductor L22 is connected to the connection point between the third transmission line 23 and the capacitor C24. The collector of the second bipolar transistor Q22 is connected to the other end of the second inductor L22. The base of the second bipolar transistor Q22 is grounded via the second resistor R22, and the emitter of the second bipolar transistor Q22 is grounded.

In order to explain this operation, a variable capacitance circuit 24 composed of a first bipolar transistor Q21, a first resistor R21 and an inductor L21, and a second bipolar transistor Q22, a second resistor R22 and an inductor L22. Attention is paid only to the variable capacitance circuit 25 configured by.

The dependency of the collector-emitter capacitance Ctr of the first (second) bipolar transistor Q21 (Q22) and the consumption current on the collector-emitter voltage is the same as in FIGS. 2 and 3 of the first embodiment. It shows various characteristics. The value of the collector-emitter capacitance Ctr is adjusted to an appropriate value according to the configuration of the high frequency switch SW3 by changing the emitter electrode area of the transistor Q21 (Q22). When the inductance of the inductor L21 (L22) whose one end is connected to the collector of the first (second) bipolar transistor Q21 (Q22) is Ls and the angular frequency used is ω, the capacitance of the variable capacitance circuit 24 (25) The value C is expressed by the following equation.

[Equation 4] Therefore, with the minimum value of the collector-emitter capacitance Ctr as Cmin and the maximum value as Cmax, the variable capacitance circuit 24 (25)
Off-state capacitance value Coff and on-state capacitance value Con
Ls, Cmax, Cmin are determined so that satisfies the following equation.

[Equation 5]

[Equation 6] That is, the reactance Ls is determined so that the capacitance Cmax and the reactance Ls cause series resonance, and the capacitances Cmin and Cmax are determined so that the variable capacitance circuit 24 (25) has sufficient isolation in the capacitance Coff. In this way, on / off control of the variable capacitance circuit 24 (25) is performed.

When performing transmission using the high frequency switch SW3 having the above structure, a negative voltage is applied to the control terminal CT20. At this time, the DC component is cut by the capacitors C21 to C24, and the voltage applied to the control terminal CT20 is applied only to the circuit including the first bipolar transistor Q21 and the second bipolar transistor Q22. The voltage applied to the control terminal CT20 turns on the first variable capacitance circuit 24 and the second variable capacitance circuit 25. When the first variable capacitance circuit 24 is turned on, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal ANT, and the transmission signal is transmitted from the antenna via the antenna terminal ANT. At this time, the second transmission line 23 is connected to the receiving terminal Rx.
Since the side is grounded by the second variable capacitance circuit 25 and resonates, its impedance becomes infinite,
Transmission signals from the transmission circuits Tx is not transmitted to the reception terminal Rx. Further, since the collector-emitter capacitor of the first bipolar transistor Q21 and the first inductor L21 whose one end is connected to the collector resonate in series,
Insertion loss is particularly reduced.

On the other hand, during reception, the control terminal CT
A positive voltage is applied to 20. At this time, since the first variable capacitance circuit 24 and the second variable capacitance circuit 25 are turned off, the reception signal from the antenna terminal ANT is transmitted to the reception terminal Rx and is not transmitted to the transmission terminal Tx.

As described above, by using the variable capacitance circuits 24 and 25 having the ON / OFF characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

(Fourth Embodiment) FIG. 6 shows a high frequency switch SW4 according to a fourth embodiment of the present invention.
It is a circuit diagram of. The high frequency switch SW4 includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception circuit.
(Not shown) is connected to the receiving terminal Rx.
One end of the first inductor L31 is connected to the transmission terminal Tx via the capacitor C31, and the other end of the first inductor L31 is connected to the collector of the first bipolar transistor Q31. A first transmission line 31 acting as a choke coil and a capacitor C32 are serially connected in series from the first inductor L31 side between one end of the first inductor L31 and the ground. A first control terminal CT30 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at the connection point between the first transmission line 31 and the capacitor C32. The base of the first bipolar transistor Q31 is grounded via the first resistor R31. The emitter of the first bipolar transistor Q31 is connected to the antenna terminal AN.
It is connected to T via a capacitor C33. Further, the collector of the first bipolar transistor Q31 is grounded via the second transmission line 32 which functions as a choke coil.

The emitter of the second bipolar transistor Q32 is connected to the emitter of the first bipolar transistor Q31, and the base of the second bipolar transistor Q32 is grounded via the second resistor R32. There is. The collector of the second bipolar transistor Q32 is connected to one end of the second inductor L32. The other end of the second inductor L32 is connected to the receiving terminal Rx via the capacitor C35. Further, a third transmission line 33 acting as a choke coil and a capacitor C34 are connected in series in order from the second inductor L32 side between the other end of the second inductor L32 and the ground. At the connection point between the third transmission line 33 and the capacitor C34,
Control circuit for switching high-frequency switches
Second control terminal CT31 to which (not shown) is connected
Is provided.

The first bipolar transistor Q31,
The first variable capacitance circuit 34 is constituted by the first resistor R31 and the first inductor L31, and the second variable capacitance circuit 35 is constituted by the second bipolar transistor Q32, the second resistor R32, and the second inductor L32. Are configured. The first variable capacitance circuit 34 and the second variable capacitance circuit 35 perform an on / off control operation based on the same principle as in the third embodiment.

When performing transmission using the high frequency switch SW4 having the above structure, a negative voltage is applied to the first control terminal CT30 and a positive voltage is applied to the second control terminal CT31. The direct current component is cut by the capacitors C31 to C35, and the voltage applied to the first control terminal CT30 and the second control terminal CT31 becomes the first voltage.
Is applied only to the circuit including the bipolar transistor Q31 and the second bipolar transistor Q32. The negative voltage applied to the first control terminal CT30 turns on the first variable capacitance circuit 34, and the positive voltage applied to the second control terminal CT31 causes the second variable capacitance circuit 35. Turns off. Therefore, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal A.
The signal is transmitted to NT, the transmission signal is transmitted from the antenna via the antenna terminal ANT, and is not transmitted to the reception terminal Rx. At this time, the first bipolar transistor Q31
Since the collector-emitter capacitor of and the first inductor L31 whose one end is connected to the collector resonate in series, the insertion loss is particularly reduced.

On the other hand, during reception, a positive voltage is applied to the first control terminal CT30 and a negative voltage is applied to the second control terminal CT31. At this time, the first variable capacitance circuit 34 is turned off and the second variable capacitance circuit 35 is turned on according to the same principle as at the time of transmission, so that the reception signal from the antenna terminal ANT is received at the reception terminal Rx. It is transmitted and is not transmitted to the transmission terminal Tx. In addition, the second
Since the collector-emitter capacitor of the bipolar transistor Q32 and the second inductor L32 whose one end is connected to the collector resonate in series, the insertion loss is particularly reduced.

As described above, by using the variable capacitance circuits 34 and 35 having the on / off characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

(Fifth Embodiment) FIG. 7 shows a high frequency switch SW5 according to a fifth embodiment of the present invention.
It is a circuit diagram of. The high frequency switch SW5 includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception circuit.
(Not shown) is connected to the receiving terminal Rx.
A first bipolar transistor Q41 is connected to the transmission terminal Tx.
Is connected via a capacitor C41. The emitter of the first bipolar transistor Q41 is grounded via the first transmission line 41 acting as a choke coil, and the base of the first bipolar transistor Q41 is grounded via the first resistor R41. . A first inductor L41 and a first capacitor C42 are serially connected in series from the collector side between the collector and the emitter of the first transistor Q41. One end of the second inductor L42 is connected to the collector of the first bipolar transistor Q41. An antenna terminal ANT is connected to the other end of the second inductor L42 via a capacitor C43. A second transmission line 42 acting as a choke coil and a capacitor C44 are connected in series in order from the second inductor L42 side between the other end of the second inductor L42 and the ground. A control terminal CT40 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at a connection point between the second transmission line 42 and the capacitor C44.

Further, one end of the third transmission line 43 is connected to the connection point between the second inductor L42 and the capacitor C43. The other end of the third transmission line 43 is connected to the receiving terminal Rx via a capacitor C46. One end of the third inductor L43 is connected to the connection point between the third transmission line 43 and the capacitor C46. The collector of the second bipolar transistor Q42 is connected to the other end of the third inductor L43. The base of the second bipolar transistor Q42 is grounded via the second resistor R42, and the second bipolar transistor Q42 is connected.
42 emitters are grounded. In addition, the fourth bipolar transistor Q42 has a fourth
The inductor L44 and the second capacitor C45 are connected in series in order from the collector side.

In order to explain the operation of the high frequency switch SW5, the first bipolar transistor Q41, the resistor R41,
A variable capacitance circuit 44 composed of a first inductance element L41, a second inductance element L42 and a first capacitor C42, a second bipolar transistor Q42,
Only the variable capacitance circuit 45 including the resistor R42, the third inductance element L43, the fourth inductance element L44 and the second capacitor C45 will be considered.

Dependence of the collector-emitter capacitance Ctr of the portion composed of the first (second) bipolar transistor Q41 (Q42) and the first resistor R41 (R42) and the consumption current on the collector-emitter voltage. Shows the same characteristics as in FIGS. 2 and 3 of the first embodiment. The value of the collector-emitter capacitance Ctr is the same as that of the transistor Q41 (Q4
By changing the emitter electrode area of 2) or the like, it is adjusted to an appropriate value according to the configuration of the high frequency switch SW5. The first (second) bipolar transistor Q41
Inductor L41 with one end connected to the collector of (Q42)
Assuming that the inductance of (L44) is Ls, the inductance of the inductor L42 (L43) connected between the collector and the emitter via the first capacitors C42 and C45 is Lp, and the angular frequency used is ω, the variable capacitance circuit 44 ( The impedance Z of 45) is expressed by the following equation.

[Equation 7] Therefore, assuming that the minimum value of the collector-emitter capacitance Ctr is Cmin and the maximum value thereof is Cmax, the variable capacitance circuit 44 (4
5) The impedance Zoff in the off state and the impedance Zon in the on state satisfy Ls, Lp, C
Determine max and Cmin.

[Equation 8]

[Equation 9] That is, the inductance Lp is determined so that the inductance Lp and the capacitance Cmin resonate in parallel, and the inductance Ls is determined so that the inductance Ls and the capacitance (Cmax-Cmin) resonate in series. Therefore, the variable capacitance circuit 44 (45) is subjected to on / off control for switching between the high isolation off state and the low insertion loss on state.

When transmission is performed using the high frequency switch SW5 having the above structure, a negative voltage is applied to the control terminal CT40. At this time, the DC component is cut by the capacitors C41 to C46, and the negative voltage applied to the control terminal CT40 is applied only to the circuit including the first bipolar transistor Q41 and the second bipolar transistor Q42. The negative voltage applied to the control terminal CT40 turns on the first variable capacitance circuit 44 and the second variable capacitance circuit 45. When the first variable capacitance circuit 44 is turned on, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal ANT, and the transmission signal is transmitted from the antenna via the antenna terminal ANT. At this time, the transmission signal from the transmission terminal Tx resonates because the third transmission line 43 is grounded on the reception terminal Rx side by the second variable capacitance circuit 45, and the impedance thereof becomes infinite. It is not transmitted to the terminal Rx. Further, since the collector-emitter capacitor of the first bipolar transistor Q41 and the second inductor L42 resonate in series, the insertion loss is particularly reduced.

On the other hand, during reception, the control terminal CT
A positive voltage is applied to 40. At this time, since the first variable capacitance circuit 44 and the second variable capacitance circuit 45 are turned off, the reception signal from the antenna terminal ANT is transmitted to the reception terminal Rx while being transmitted to the transmission terminal Tx. Not done. At this time, the first bipolar transistor Q
Since the collector-emitter capacitor of 41 and the first inductor L41 resonate in parallel, the isolation between the antenna terminal ANT side and the transmission terminal Tx side is further improved.

As described above, by using the variable capacitance circuits 44 and 45 having the on / off characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

(Sixth Embodiment) FIG. 8 shows a high frequency switch SW6 according to a sixth embodiment of the present invention.
It is a circuit diagram of. The high frequency switch SW6 includes an antenna terminal ANT to which an antenna (not shown) is connected, a transmission terminal Tx to which a transmission circuit (not shown) is connected, and a reception circuit.
(Not shown) is connected to the receiving terminal Rx.
One end of the first inductor L51 is connected to the transmission terminal Tx via a capacitor C51. The collector of the first bipolar transistor Q51 is connected to the other end of the first inductor L51. Between the one end of the first inductor L51 and the ground, a first transmission line 51 acting as a choke coil and a capacitor C52 are connected to the first inductor L51.
Connect in series from the 51 side. A first control terminal CT50 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at the connection point between the first transmission line 51 and the capacitor C52. The base of the first bipolar transistor Q51 is grounded via the first resistor R51. First above
The second inductor L52 and the first capacitor C53 are serially connected in series from the collector side between the collector and the emitter of the bipolar transistor Q51. The emitter of the first bipolar transistor Q51 is connected to the antenna terminal A.
It is connected to NT through a capacitor C54. further,
The emitter of the first bipolar transistor Q51 is grounded via the second transmission line 52 which functions as a choke coil.

The emitter of the second bipolar transistor Q52 is connected to the emitter of the first bipolar transistor Q51. The base of the second bipolar transistor Q52 is grounded via the second resistor R52. A third inductor L53 and a second capacitor C55 are serially connected in series from the collector side between the collector and the emitter of the second bipolar transistor Q52. One end of a fourth inductor L54 is connected to the collector of the second bipolar transistor Q52. The other end of the fourth inductor L54 is connected to the receiving terminal Rx via the capacitor C57. A third transmission line 53 acting as a choke coil and a capacitor C56 are connected in series in order from the fourth inductor L54 side between the other end of the fourth inductor L54 and the ground. A second control terminal CT51 to which a control circuit (not shown) for switching the high frequency switch is connected is provided at the connection point between the third transmission line 53 and the capacitor C56.

The first bipolar transistor Q51,
The first resistor R51, the first inductor L51, the second inductor L52, and the first capacitor C53 constitute the first variable capacitance circuit 54, and the second bipolar transistor Q52, the second resistor R52, and the second resistor R52 The third variable capacitance circuit 55 is constituted by the third inductor L53, the fourth inductor L54 and the second capacitor C55. The first variable capacitance circuit 54 and the second variable capacitance circuit 55 perform on / off control operation transmission on the same principle as in the fifth embodiment.

When transmitting using the high-frequency switch SW6 having the above structure, a negative voltage is applied to the first control terminal CT50 and a positive voltage is applied to the second control terminal. The direct current component is cut by the capacitors C51 to C57, and the voltage applied to the first control terminal CT50 and the second control terminal CT51 is applied only to the circuit including the first bipolar transistor Q51 and the second bipolar transistor Q52. To be done. This first
The first variable capacitance circuit 54 is turned on by the negative voltage applied to the control terminal CT50, and the second variable capacitance circuit 55 is turned off by the positive voltage applied to the second control terminal CT51. It becomes a state. Therefore, the transmission signal from the transmission terminal Tx is transmitted to the antenna terminal A.
The signal is transmitted to NT, the transmission signal is transmitted from the antenna via the antenna terminal ANT, and is not transmitted to the reception terminal Rx. At this time, the first bipolar transistor Q51
Since the collector-emitter capacitor of and the first inductor L51 resonate in series, the insertion loss is particularly reduced.
Further, since the collector-emitter capacitor of the second bipolar transistor Q52 and the third inductor L53 resonate in parallel, the antenna terminal ANT and the receiving terminal Rx are connected.
The isolation with the side is further improved.

On the other hand, during reception, a positive voltage is applied to the first control terminal CT50 and a negative voltage is applied to the second control terminal CT51. At this time, the first variable capacitance circuit 54 is turned off and the second variable capacitance circuit 55 is turned on according to the same principle as at the time of transmission, so that the received signal from the antenna terminal ANT goes to the receiving terminal Rx. It is transmitted and is not transmitted to the transmission terminal Tx. At this time, since the collector-emitter capacitor of the first bipolar transistor Q51 and the second inductor L52 resonate in parallel, the isolation between the antenna terminal ANT and the transmission terminal Tx side is further improved. Further, since the collector-emitter capacitor of the second bipolar transistor Q52 and the fourth inductor L54 resonate in series, the insertion loss is particularly reduced.

As described above, by using the variable capacitance circuits 54 and 55 having the on / off characteristics in the high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

In the first to sixth embodiments, the high frequency switches SW1 to SW6 are the same type of variable capacitance circuits 4,
Although 5 ...

In the first to sixth embodiments, the NP
Although N type bipolar transistors Q1 to Q52 are used,
A PNP type bipolar transistor may be used.

[0084]

As is apparent from the above, the high frequency switch according to the invention of claim 1 is connected in series between the bipolar transistor whose base is grounded through the resistor and the collector-emitter of the bipolar transistor. and a variable capacitance circuit having an inductor and a capacitor, which uses the collector and emitter of the bipolar transistor as a terminal, Kore of the bipolar transistor
The reverse bias is applied to the diode between the
Turns off the polar transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In addition, the bipolar transistor is turned off in terms of direct current.
Moreover, it is turned on in terms of alternating current.

Therefore, according to the high frequency switch of the first aspect of the present invention, when a reverse bias is applied to the collector-base diode and the emitter-base diode of the bipolar transistor, the variable capacitance circuit operates in both direct current and high frequency. Is also turned off, and the collector-emitter capacitor of the bipolar transistor and the inductor resonate in parallel, which further improves the isolation in the off state. On the other hand, when a forward bias is applied to the collector-base diode of the bipolar transistor, the variable capacitance circuit is turned off in terms of direct current and turned on in terms of high frequency. Therefore, by using the variable capacitance circuit having the on / off characteristics in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

The high-frequency switch according to the invention of claim 2 is a high-frequency switch which is connected to the transmission circuit, the reception circuit and the antenna and which switches the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna. An emitter is connected to the transmitter circuit side, a collector is connected to the antenna side, and a base is grounded via a first resistor; and a collector of the first bipolar transistor. -The first inductor and the first capacitor connected in series between the emitters, the transmission line connected between the antenna and the receiving circuit, the collector is connected to the receiving circuit side, and the base is A second bipolar transistor which is grounded via a second resistor and whose emitter is grounded; and a collector of the second bipolar transistor And a second inductor and a second capacitor connected in series between the emitter, the
Between collector and base of first and second bipolar transistors
Applying reverse bias to the diode, the first and second bipolar
The off-state transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In terms of direct current, the first and second bipolar transistors are
It is turned off and turned on in terms of alternating current .

Therefore, according to the high frequency switch of the second aspect of the present invention, a forward bias is applied to the collector-base diodes of the first and second bipolar transistors so that they are off in terms of direct current and high in frequency. When turned on, the transmission signal from the transmission circuit is transmitted to the antenna side, while the reception circuit side of the transmission line is grounded and resonates, causing the impedance to become infinite, so the transmission signal is received. Not transmitted to the circuit side. On the other hand, by applying a reverse bias to the collector-base diode and the emitter-base diode of the first and second bipolar transistors to turn them off both in terms of direct current and high frequency, The received signal is transmitted to the receiving circuit, but is not transmitted to the transmitting circuit. At this time, the collector of the first bipolar transistor
-Since the inter-emitter capacitor and the first inductor resonate in parallel, the isolation in the off state is further improved. Therefore, by using a circuit having an on / off characteristic in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

The high frequency switch according to the invention of claim 3 is a high frequency switch which is connected to the transmitting circuit, the receiving circuit and the antenna and which switches the connection between the transmitting circuit and the antenna and the connection between the receiving circuit and the antenna. A collector connected to the transmitter circuit side, an emitter connected to the antenna side, and a base grounded via a first resistor; and a collector of the first bipolar transistor. -The first inductor and the first capacitor connected in series between the emitters, the collector is connected to the receiving circuit side, the emitter is connected to the antenna side, and the base is grounded via the second resistor. And a second bipolar transistor connected in series between the collector and the emitter of the second bipolar transistor. And a inductor and a second capacitor, first, Kore of the second bipolar transistor
Applying a reverse bias to the diode between the base and the base,
The second bipolar transistor is turned on DC and AC.
While it is in the off state, the forward
First and second bipolar transistors with bias applied
Is turned off in terms of direct current and turned on in terms of alternating current .

Therefore, according to the high frequency switch of the third aspect of the present invention, a forward bias is applied to the collector-base diode of the first bipolar transistor to turn it off in terms of direct current and turn on in terms of high frequency. The collector of the second bipolar transistor is
By applying a reverse bias to the base-to-base diode and emitter-to-base diode to turn them off both in terms of direct current and high frequency, the transmission signal from the transmission circuit is transmitted to the antenna side, while the above transmission is performed. Since the receiving circuit side of the line is grounded and resonates and the impedance becomes infinite, the transmission signal is not transmitted to the receiving circuit side. At this time, the collector of the second bipolar transistor
Since the inter-emitter capacitor and the second inductor resonate in parallel, the isolation in the off state is further improved. On the other hand, a forward bias is applied to the collector-base diode of the second bipolar transistor so that it is turned off in terms of direct current and turned on in terms of high frequency, while the collector of the first bipolar transistor is turned on.
By applying a reverse bias to the base-to-base diode and the emitter-to-base diode to turn them off both in terms of direct current and high frequency, the reception signal from the antenna is transmitted to the reception circuit, while it is transmitted to the transmission circuit. Is not transmitted. At this time, since the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in parallel, the isolation in the off state is further improved. Therefore, by using a circuit having an on / off characteristic in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

The high frequency switch according to the present invention is a variable capacitance circuit having a bipolar transistor whose base is grounded via a resistor and an inductor having one end connected to the collector or emitter of the bipolar transistor. the state, and are not using the emitter or collector of the bipolar transistor as a terminal, the server
Ipolar transistor collector-base diode
Reverse bias is applied to the bipolar transistor
The collector-base
A bipolar transistor by applying a forward bias between
The DC is off and the AC is on.
To do.

Therefore, according to the high frequency switch of the invention of claim 4, the collector of the bipolar transistor is
-When a reverse bias is applied to the diode between the base and the diode between the emitter and the base, the variable capacitance circuit is turned off both in terms of direct current and high frequency, while forward bias is applied to the diode between the collector and base of the bipolar transistor. , The variable capacitance circuit is turned off in terms of direct current and turned on in terms of high frequency. At this time, since the collector-emitter capacitor of the bipolar transistor and the inductor whose one end is connected to the collector or the emitter resonate in series, the insertion loss is particularly reduced. Therefore, by using the variable capacitance circuit having the on / off characteristics in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

Further, the high frequency switch of the invention of claim 5 is a high frequency switch which is connected to the transmission circuit, the reception circuit and the antenna and which switches the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna. A first bipolar transistor whose emitter is connected to the transmitter circuit side and whose base is grounded via a first resistor, and one end of which is connected to the collector of the first bipolar transistor and whose other end is The first connected to the antenna side
An inductor, a transmission line connected between the antenna and the receiving circuit, a second inductor having one end connected to the receiving circuit side of the transmission line, and a collector at the other end of the second inductor. is connected, the base is grounded via a second resistor, and a second bipolar transistor whose emitter is grounded, first, second bipolar Trang
Reverse bias the collector-base diode of the transistor
Applying a direct current to the first and second bipolar transistors
And while it is turned off in the alternating current, the collector-base
A forward bias is applied between the first and second bipolar devices.
The transistor is off in terms of direct current and in terms of alternating current
It is to be turned on .

Therefore, according to the high-frequency switch of the fifth aspect of the present invention, a forward bias is applied to the collector-base diodes of the first and second bipolar transistors so that they are off in terms of direct current and high-frequency. In the ON state, the transmission signal from the transmission circuit is transmitted to the antenna side, while the reception circuit side of the transmission line is grounded and resonates, and the impedance becomes infinite. Not transmitted to the receiving circuit side. At this time, since the collector-emitter capacitor of the first bipolar transistor and the first inductor whose one end is connected to the collector or the emitter resonate in series, the insertion loss is particularly reduced. On the other hand, by applying a reverse bias to the collector-base diode and the emitter-base diode of the first and second bipolar transistors to turn them off both in terms of direct current and high frequency, While the received signal of 1 is transmitted to the receiving circuit, it is not transmitted to the transmitting circuit. Therefore, by using a circuit having an on / off characteristic in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

The high-frequency switch according to the invention of claim 6 is a high-frequency switch which is connected to the transmitting circuit, the receiving circuit and the antenna and which switches the connection between the transmitting circuit and the antenna and the connection between the receiving circuit and the antenna. A first inductor whose one end is connected to the transmission circuit side, the other end of the first inductor is connected to the collector, the emitter is connected to the antenna side, and the base is connected via the first resistor. One end is connected to a grounded first bipolar transistor, a second bipolar transistor whose emitter is connected to the antenna side and whose base is connected via a second resistor, and a connector of the second bipolar transistor. is, and a second inductor whose other end is connected to the receiving circuit side, first, second Bipolar
Reverse transistor to the collector-base diode of the transistor.
First and second bipolar transistors with bias applied
The DC and AC off states, while
Apply a forward bias between the base and the base to
The Ipolar transistor is off in terms of DC and AC
The purpose is to turn it on .

Therefore, according to the high frequency switch of the sixth aspect of the present invention, a forward bias is applied to the collector-base diode of the first bipolar transistor to turn it off in terms of direct current and turn on in terms of high frequency. The collector of the second bipolar transistor is
By applying a reverse bias to the base-to-base diode and the emitter-to-base diode to turn them off both in terms of direct current and high frequency, the transmission signal from the transmission circuit is transmitted to the antenna side. Since the receiving circuit side of the transmission line is grounded and resonates and the impedance becomes infinite, the transmission signal is not transmitted to the receiving circuit side.
At this time, since the collector-emitter capacitor of the first bipolar transistor and the first inductor whose one end is connected to the collector or the emitter resonate in series, the insertion loss is particularly reduced. On the other hand, the collector of the second bipolar transistor - the base between the diode by applying a forward bias, DC to the OFF state, while the on state to the high frequency, co the first bipolar transistor collector - By applying a reverse bias to the diode between the base and the diode between the emitter and the base to turn them off both in terms of direct current and high frequency, the reception signal from the antenna is transmitted to the reception circuit, while the transmission circuit is transmitted. Is not transmitted to. At this time, one end of the second bipolar transistor is connected to the collector-emitter capacitor and the collector or the emitter.
Insertion loss is particularly reduced because of the series resonance with the inductor. Therefore, by using a circuit having an on / off characteristic in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

According to a seventh aspect of the present invention, there is provided a high frequency switch in which a bipolar transistor whose base is grounded via a resistor, a first inductor and a first inductor which are connected in series between a collector and an emitter of the bipolar transistor. A variable capacitance circuit having a capacitor and a second inductor whose one end is connected to the collector or emitter of the bipolar transistor, wherein the emitter or collector of the bipolar transistor is a terminal, and the other end of the second inductor is a terminal. der those is, bipolar tiger
Reverse bias on diode between collector and base of transistor
Is applied to make the bipolar transistor DC and AC
While it is in the off state, it is forward between the collector and the base.
Applying forward bias to make bipolar transistor DC-like
Is turned off and is turned on in terms of alternating current.
It

[0097] Thus, according to the high frequency switch of the invention of claim 7, co of the bipolar transistor collector
-When a reverse bias is applied to the diode between the base and the diode between the emitter and the base, the variable capacitance circuit is turned off both in terms of direct current and high frequency. At this time, since the collector-emitter capacitor of the bipolar transistor and the inductor resonate in parallel, the isolation in the off state is further improved. On the other hand, when a forward bias is applied to the collector-base diode of the bipolar transistor, the variable capacitance circuit is turned off in terms of direct current and turned on in terms of high frequency. At this time, since the collector-emitter capacitor of the bipolar transistor and the inductor whose one end is connected to the collector or the emitter resonate in series, the insertion loss is particularly reduced. Therefore, by using the variable capacitance circuit having the on / off characteristics in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

[0098] Further, the high frequency switch of the invention of claim 8, the transmission circuit, connected to the receiving circuit and the antenna, the high-frequency switch for switching the connection between the connection and the reception circuit and the antenna of the transmitting circuit and the antenna A first bipolar transistor whose emitter is connected to the transmitter circuit side and whose base is grounded via a first resistor; and a collector of the first bipolar transistor.
-A first inductor and a first capacitor connected in series between the emitters, a second inductor having one end connected to the collector of the first bipolar transistor and the other end connected to the antenna side, A transmission line connected between the antenna and the receiving circuit, a third inductor having one end connected to the receiving circuit side, a collector connected to the other end of the third inductor, and a base having a second A second bipolar transistor grounded through a resistor and an emitter grounded, and a collector of the second transistor.
A fourth inductor and a second inductor connected in series between the emitters
The first and second bipolar transistors are equipped with
Reverse bias is applied to the collector-base diode of the star
In addition, whether the first and second bipolar transistors are direct current type
The above-mentioned collector-base while being turned off in alternating current
A forward bias is applied between the first and second bipolar
The transistor is off for DC and off for AC.
It is to be turned on .

Therefore, according to the high frequency switch of the eighth aspect of the present invention, a forward bias is applied to the collector-base diodes of the first and second bipolar transistors so that they are off in terms of direct current and high in frequency. In the ON state, the transmission signal from the transmission circuit is transmitted to the antenna side, while the reception circuit side of the transmission line is grounded and resonates, and the impedance becomes infinite. Not transmitted to the receiving circuit side. At this time, since the collector-emitter capacitor of the first bipolar transistor and the second inductor whose one end is connected to the collector or the emitter resonate in series, the insertion loss is particularly reduced. On the other hand, by applying a reverse bias to the collector-base diode and the emitter-base diode of the first and second bipolar transistors to turn them off both in terms of direct current and high frequency, While the received signal of 1 is transmitted to the receiving circuit, it is not transmitted to the transmitting circuit. At this time, since the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in parallel,
The isolation in the off state is further improved. Therefore, by using the variable capacitance circuit having the on / off characteristics in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

A high frequency switch according to a ninth aspect of the present invention is a high frequency switch which is connected to a transmission circuit, a reception circuit and an antenna and which switches the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna. A first inductor whose one end is connected to the transmission circuit side, the other end of the first inductor is connected to the collector, the emitter is connected to the antenna side, and the base is the first resistor. A first bipolar transistor grounded through the collector of the first bipolar transistor
-A second inductor and a first capacitor connected in series between the emitters, a second bipolar transistor having the emitter connected to the antenna side and a base grounded via a second resistor, A third inductor and a second capacitor connected in series between the collector and the emitter of the second bipolar transistor, one end of which is connected to the collector of the second bipolar transistor, and the other end of which is connected to the receiving circuit side. With a fourth inductor connected ,
Collector-base of the first and second bipolar transistors
Reverse bias is applied to the diode between the first and second diodes.
Turns off the polar transistor DC and AC
Meanwhile, a forward bias is applied between the collector and base.
In addition, the first and second bipolar transistors are made DC
Is in the off state and is in the on state in terms of alternating current .

Therefore, according to the high frequency switch of the present invention, a forward bias is applied to the collector-base diode of the first bipolar transistor so that the direct current is off and the high frequency is on. The collector of the second bipolar transistor is
By applying a reverse bias to the base-to-base diode and the emitter-to-base diode to turn them off both in terms of direct current and high frequency, the transmission signal from the transmission circuit is transmitted to the antenna side. Since the receiving circuit side of the transmission line is grounded and resonates and the impedance becomes infinite, the transmission signal is not transmitted to the receiving circuit side.
At this time, since the collector-emitter capacitor of the first bipolar transistor and the first inductor resonate in series, the insertion loss is particularly reduced. On the other hand, a forward bias is applied to the collector-base diode of the second bipolar transistor to turn it off in terms of direct current and on in terms of high frequency, while the collector-base of the first bipolar transistor. By applying a reverse bias to the diode between the emitter and the diode between the emitter and the base, and turning them off both in terms of direct current and high frequency, the reception signal from the antenna is transmitted to the reception circuit, while it is transmitted to the transmission circuit. Is not transmitted. At this time, since the collector-emitter capacitor of the first bipolar transistor and the second inductor resonate in parallel, the isolation in the off state is further improved. Therefore, by using the variable capacitance circuit having the on / off characteristics in such a high frequency band, it is possible to realize a high frequency switch with low current consumption and low insertion loss.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a high frequency switch according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a relationship between a collector-emitter voltage and a capacitance of the variable capacitance circuit of the high frequency switch.

FIG. 3 is a diagram showing a relationship between collector-emitter voltage and consumption current of the variable capacitance circuit of the high frequency switch.

FIG. 4 is a circuit diagram of a high frequency switch according to a second embodiment of the present invention.

FIG. 5 is a circuit diagram of a high frequency switch according to a third embodiment of the invention.

FIG. 6 is a circuit diagram of a high frequency switch according to a fourth embodiment of the present invention.

FIG. 7 is a circuit diagram of a high frequency switch according to a fifth embodiment of the present invention.

FIG. 8 is a circuit diagram of a high frequency switch according to a sixth embodiment of the present invention.

FIG. 9 is a circuit diagram of a conventional high frequency switch.

FIG. 10 is a diagram showing a relationship between a consumption current of a diode of the high frequency switch and a high frequency operation resistance.

[Explanation of symbols]

1, 2, 3 ... Transmission line, 4, 5 ... Variable capacitance circuit, Q1 ... First
Bipolar transistor, Q2 ... second bipolar transistor, L1 ... first inductor, L2 ... second inductor, C2 ... first capacitor, C5 ... second capacitor, R1 ... first resistance, R2 ... 2 resistors, C1, C3, C4,
C6 ... Capacitor.

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H03K 17/62 H01P 1/15 H04B 1/44

Claims (9)

(57) [Claims] 1. A bipolar transistor whose base is grounded via a resistor, an inductor and a capacitor connected in series between the collector and the emitter of the bipolar transistor, and a collector and an emitter of the bipolar transistor. a variable capacitance circuit according to the terminal, the collector of the bipolar transistor - to base die
Reverse bias is applied to the bipolar transistor
While turning off the star in both DC and AC,
A forward bias is applied between the inductor and the base to
The polar transistor is off in terms of DC and AC
Is a high-frequency switch that is turned on . 2. A high-frequency switch connected to a transmission circuit, a reception circuit, and an antenna, for switching the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna. A first bipolar transistor having an emitter connected thereto, a collector connected to the antenna side, and a base grounded via a first resistor, and a collector-emitter connected in series between the collector and the emitter of the first bipolar transistor. A first inductor and a first capacitor, a transmission line connected between the antenna and the receiving circuit, a collector connected to the receiving circuit side, and a base via a second resistor. Connected in series between the second bipolar transistor whose emitter is grounded and the collector-emitter of the second bipolar transistor. And a second inductor and a second capacitor that is, the first collector of the second bipolar transistor - base
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC.
High-frequency switch, characterized in that that. 3. A high frequency switch connected to a transmission circuit, a reception circuit and an antenna for switching connection between the transmission circuit and the antenna and connection between the reception circuit and the antenna. A collector is connected, an emitter is connected to the antenna side, and a base is connected in series between a collector and an emitter of the first bipolar transistor whose base is grounded via a first resistor. A first inductor and a first capacitor, a collector connected to the receiving circuit side, an emitter connected to the antenna side, and a second bipolar transistor whose base is grounded via a second resistor; A second inductor and a second capacitor connected in series between the collector and the emitter of the second bipolar transistor. With the door, the first collector of the second bipolar transistor - base
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC.
High-frequency switch, characterized in that that. 4. A bipolar transistor whose base is grounded via a resistor, and an inductor whose one end is connected to the collector or emitter of the bipolar transistor, and whose emitter or collector is the terminal. In addition, a variable capacitance circuit having the other end of the inductor as a terminal is provided , and a collector-base die of the bipolar transistor is provided .
Reverse bias is applied to the bipolar transistor
While turning off the star in both DC and AC,
A forward bias is applied between the inductor and the base to
The polar transistor is off in terms of DC and AC
Is a high-frequency switch that is turned on . 5. A high-frequency switch connected to a transmission circuit, a reception circuit, and an antenna, for switching the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna, wherein the high-frequency switch is connected to the transmission circuit side. A first bipolar transistor whose emitter is connected and whose base is grounded via a first resistor, and one end of which is connected to the collector of the first bipolar transistor and whose other end is connected to the antenna side A first inductor; a transmission line connected between the antenna and the receiving circuit; and a second line having one end connected to the receiving circuit side of the transmission line.
And inductors, the collector to the other end of the second inductor is connected, the base is grounded via a second resistor, and a second bipolar transistor whose emitter is grounded, the first, second Bipolar transistor collector
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC.
High-frequency switch, characterized in that that. 6. A high-frequency switch connected to a transmission circuit, a reception circuit, and an antenna, for switching the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna, wherein the high-frequency switch is connected to the transmission circuit side. A first inductor whose one end is connected, the other end of the first inductor is connected to the collector, the emitter is connected to the antenna side, and the base is grounded via a first resistor. A transistor, a second bipolar transistor whose emitter is connected to the antenna side and whose base is connected via a second resistor, and one end of which is connected to the connector of the second bipolar transistor and the other end of which is the receiving side and a second inductor connected to the circuit side, the first collector of the second bipolar transistor - base
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC.
High-frequency switch, characterized in that that. 7. A bipolar transistor whose base is grounded via a resistor, a first inductor and a first capacitor connected in series between the collector and the emitter of the bipolar transistor, and a collector or an emitter of the bipolar transistor. to a second inductor having one end connected, with the emitter or collector of the bipolar transistor and the terminal includes a variable capacitance circuit that the other end of the second inductor terminal, the bipolar transistor Collector-base die
Reverse bias is applied to the bipolar transistor
While turning off the star in both DC and AC,
A forward bias is applied between the inductor and the base to
The polar transistor is off in terms of DC and AC
Is a high-frequency switch that is turned on . 8. The transmission circuit is connected to the receiving circuit and the antenna, a <br/> high-frequency switch for switching the connection between the transmission circuit and the connections and the receiving circuit and the antenna of the antenna A first bipolar transistor whose emitter is connected to the transmitter circuit side and whose base is grounded via a first resistor; and a first bipolar transistor which is connected in series between the collector and the emitter of the first bipolar transistor. A first inductor and a first capacitor, a second inductor whose one end is connected to the collector of the first bipolar transistor and the other end of which is connected to the antenna, and between the antenna and the receiving circuit. A connected transmission line, and a third end whose one end is connected to the receiving circuit side of the transmission line.
And a second bipolar transistor having a collector connected to the other end of the third inductor, a base grounded via a second resistor, and an emitter grounded, and a collector of the second transistor. A fourth inductor and a second capacitor connected in series between the emitters are provided , and the collector and base of the first and second bipolar transistors are provided .
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC .
High-frequency switch, characterized in that that. 9. A high-frequency switch connected to a transmission circuit, a reception circuit, and an antenna, for switching the connection between the transmission circuit and the antenna and the connection between the reception circuit and the antenna, wherein the high-frequency switch is connected to the transmission circuit side. A first inductor, one end of which is connected, the other end of the first inductor is connected to a collector, an emitter is connected to the antenna side, and a base is grounded via a first resistor. Bipolar transistor, a second inductor and a first capacitor connected in series between the collector and the emitter of the first bipolar transistor, the emitter is connected to the antenna side, and the base is the second resistor. A second bipolar transistor grounded through a third bipolar transistor connected in series between the collector and the emitter of the second bipolar transistor. Inductor and a second capacitor, one end to the collector of the second bipolar transistor is connected, and a fourth inductor and the other end to the receiving circuit side is connected, the first, second bipolar transistor Collectors-
Applying a reverse bias to the diode between the source and
Turn off the second bipolar transistor in both DC and AC
While it is in the state
Apply the ass to apply the first and second bipolar transistors.
Switch is off for DC and on for AC.
High-frequency switch, characterized in that that.