JP4337613B2 - Wireless transmission circuit - Google Patents

Description

  The present invention relates to a wireless transmission circuit that performs communication using pulses.

  In recent years, attention has been paid to an ultra wide band (UWB) communication system that performs ultra-wideband communication using a pulse signal sequence composed of pulse signals synchronized with a predetermined cycle timing as one of high-speed wireless transmission systems. Yes. In UWB communication, communication is performed without using a carrier wave, for example, by using a pulse signal string composed of a very fine short pulse signal having a pulse width of 1 nsec or less (see, for example, Patent Document 1).

  FIG. 16 is a circuit diagram showing a wireless transmission circuit used for UWB communication according to the background art. The wireless transmission circuit shown in FIG. 16 is an H-bridge type antenna driving circuit that drives an LCR (Large-Current Radiator) antenna, and a series circuit of a PMOS transistor P101 and an NMOS transistor N101 between a power source and ground, A series circuit of a PMOS transistor P102 and an NMOS transistor N102 is connected, and an LCR antenna 105 is connected between a connection point between the transistors P101 and N101 and a connection point between the transistors P102 and N102.

  FIG. 17 is an explanatory diagram for explaining an example of the operation of the wireless transmission circuit illustrated in FIG. 16. First, when the transistors P101 and P102 are on and the transistors N101 and N102 are off, the antenna current Iant does not flow through the LCR antenna 105. Next, when the transistors P101 and N102 are turned on and the transistors P102 and N101 are turned off, the positive current + I flows through the LCR antenna 105 as the antenna current Iant. When the antenna current Iant rises, the positive polarity is obtained from the LCR antenna 105. The pulse signal is emitted.

  Next, when the transistors N101 and N102 are turned on and the transistors P101 and P102 are turned off, the antenna current Iant changes from the current + I to zero, and a negative pulse signal is emitted from the LCR antenna 105 when the antenna current Iant falls. The In this case, “1” in the transmission data is represented by a combination of a positive pulse signal and a negative pulse signal emitted thereafter.

  Next, when the transistors P102 and N101 are turned on and the transistors P101 and N102 are turned off, a negative current −I flows through the LCR antenna 105 as the antenna current Iant, and from the LCR antenna 105 when the antenna current Iant falls. A negative pulse signal is emitted. Next, when the transistors P101 and P102 are turned on and the transistors N101 and N102 are turned off, the antenna current Iant changes from the current −I to zero, and a positive pulse signal is radiated from the LCR antenna 105 when the antenna current Iant rises. The In this case, “0” in the transmission data is represented by a combination of the negative pulse signal and the positive pulse signal emitted thereafter.

Thus, in UWB communication, for example, data is expressed by inverting the polarity of a pulse signal corresponding to “1” and “0” of transmission data. At this time, the time width of the pulse signal is about 300 ps to 500 ps.
JP 2002-335188 A

  By the way, in the H-bridge type antenna driving circuit as described above, the negative pulse signal is emitted from the LCR antenna 105 until the negative pulse signal is emitted after the positive pulse signal is emitted from the LCR antenna 105. DC current of + I and −I continues to flow through the LCR antenna 105 from the time of radiating to the time of radiating the positive pulse signal. For this reason, there is a disadvantage that the current consumption for driving the LCR antenna 105 increases. In particular, in a wireless transmission circuit operated by a battery, an increase in current consumption causes a decrease in battery life, so the influence is significant.

  The present invention has been made in view of such problems, and provides a wireless transmission circuit capable of reducing current consumption for driving an antenna in wireless communication in which communication is performed using pulses. With the goal.

In order to achieve the above object, a wireless transmission circuit according to the present invention is a wireless transmission circuit in which an antenna current corresponding to a transmission signal is supplied to an antenna provided outside for wireless communication that performs communication using pulses. A series circuit of a first switching element, a first capacitor, and the antenna connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground; A second switching element that is connected between a connection point between the capacitor and the antenna and the ground and is turned on to bypass a transient current supplied from the first capacitor to the antenna; and the transmission signal first time delay signal Ru is turning on the first switching element in order to emit a positive pulse from the antenna, in accordance with the time width of the pulse in accordance with By supplying only delays to said second switching element, characterized in that a first delay section for turning on the second switching element is also delayed by first delay time from the switching element It is said.
A wireless transmission circuit according to the present invention is a wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using a pulse, and is provided on the secondary side. A transformer connected to the antenna; a first switching element connected between a first power supply unit that supplies a predetermined antenna driving voltage; and a ground; a primary side of the transformer; Are connected between the connection point of the series circuit, the first capacitor and the primary side of the transformer, and the ground, and are supplied from the first capacitor to the primary side of the transformer by being turned on. a second switching element for bypassing the transient current, Ru turns on the first switching element in order to emit a positive pulse from the antenna in response to the transmission signal No. and by supplying to the second switching element delayed by a first delay time corresponding to the duration of the pulse, the only delay the first delay time than the first switching element a And a delay unit for turning on the switching elements.

  Further, in the above-described wireless transmission circuit, the second switching element is a MOS transistor, and further includes a voltage application circuit that increases a source-drain voltage of the MOS transistor, and the MOS transistor has a source-drain relationship. It is characterized in that the transient current is bypassed by a current.

  The wireless transmission circuit described above further includes a third switching element that discharges the first capacitor when turned on, and the control unit turns off the first switching element after turning off the first switching element. The switching element is turned on.

Further, in the above wireless transmission circuit, the first switching element is interposed between the first power supply unit and the first capacitor, and the control unit is configured to transmit the antenna according to the transmission signal. It is characterized by changing the driving voltage.

  Further, in the above-described wireless transmission circuit, when the second switching element is turned on, the transient current supplied from the first capacitor to the antenna is bypassed, and the antenna has a direction opposite to the transient current. And a fourth switching element that, when turned on, supplies a transient current in the same direction as the transient current to the antenna via a second capacitor. The first switching element is turned on in response to the transmission signal, the second switching element is turned on by delaying the first delay time, and a second delay time corresponding to the time width of the pulse This is characterized in that the fourth switching element is turned on with a delay of only a delay.

  In the wireless transmission circuit described above, the control unit generates the delay time using a gate delay.

Further, the above-described wireless transmission circuit is a wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using pulses, and has a predetermined antenna driving voltage. A series circuit of the first switching element, the first capacitor, and the antenna, and a connection point between the first capacitor and the antenna. A second switching element that is connected to ground and that is turned on to bypass a transient current supplied from the first capacitor to the antenna; and a connection point between the first capacitor and the antenna A third capacitor connected at one end and a predetermined antenna driving voltage are supplied to the terminal of the antenna on the opposite side with the antenna in between. It is connected between the second power supply unit and the other end of said third capacitor, and transient current from the first capacitor to the antenna via the third capacitor by being turned on is supplied to the antenna Is connected between the fifth switching element for supplying the reverse current in the reverse direction, the connection point between the antenna and the other end of the third capacitor, and the ground, and is turned on to turn on the third switching element. A sixth switching element that bypasses a transient current supplied from a capacitor to the antenna, and a positive pulse from the antenna in response to the transmission signal, the second switching element and the fifth The switching element is turned off, the first switching element and the sixth switching element are turned on, and then delayed by the first delay time. When the second switching element is turned on and a negative pulse is radiated from the antenna, the first switching element and the sixth switching element are turned off, and the second switching element and the fifth switching element are turned off. And a controller that turns on the sixth switching element by delaying the switching element after turning on the first delay time.
Further, a wireless transmission circuit for supplying an antenna current according to a transmission signal to an antenna provided outside for wireless communication that performs communication using a pulse, a transformer having the antenna connected to a secondary side, A series circuit of a first switching element, a first capacitor, and a primary side of the transformer, connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground; The second switching is connected between the connection point of the capacitor and the primary side of the transformer and the ground, and is turned on to bypass the transient current supplied from the first capacitor to the primary side of the transformer. and the element, the first sandwiching at the primary side of the opposite side of the transformer terminals between the transformer viewed from the connection point of the capacitor and the primary side of the transformer, one end connected Wherein the third capacitor is connected between the other end of the third capacitor and the second power supply unit for supplying a predetermined antenna drive voltage, via a third capacitor by being turned on a fifth switching element for supplying a reverse transient current and transient current supplied from the first capacitor to the transformer, a connection point between the other end of the third capacitor and the primary side of the transformer, A sixth switching element that is connected to the ground and that is turned on to bypass a transient current supplied from the third capacitor to the primary side of the transformer; and, depending on the transmission signal, from the antenna When radiating a positive pulse, the second switching element and the fifth switching element are turned off, and the first switching element and the sixth switching element are turned off. When the second switching element is turned on after being delayed by the first delay time after the turning element is turned on, and the negative polarity pulse is radiated from the antenna, the first switching element and the first switching element are turned on. A control unit that turns off the sixth switching element, turns on the second switching element, and turns on the fifth switching element, and then turns on the sixth switching element by delaying by the first delay time. It is characterized by providing.

  In the radio transmission circuit having such a configuration, a transient current is supplied to the antenna according to the transmission signal, and the transient current supplied to the antenna is bypassed with a delay corresponding to the time width of the pulse used for communication. Thus, a positive pulse can be emitted from the antenna, so that the antenna can be driven by a transient current, and current consumption for driving the antenna can be reduced.

  Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.

(First embodiment)
FIG. 1 is a circuit diagram showing an example of the configuration of a wireless transmission circuit according to the first embodiment of the present invention. In the wireless transmission circuit 1 shown in FIG. 1, the antenna driving voltage VDD ₁ is supplied to the source of the PMOS transistor P1 corresponding to the first switching element, and the drain is connected to the ground via the resistor R1. A connection point (point A) between the drain of the transistor P1 and the resistor R1 is connected to the ground via the capacitor C1 corresponding to the first capacitor and the primary side of the differential output conversion element L1 made of, for example, a transformer. An antenna AN1 is connected to the secondary side of the differential output conversion element L1. For example, a loop antenna is used as the antenna AN1. The drain of the NMOS transistor N1 corresponding to the second switching element is connected to the connection point (point B) between the capacitor C1 and the differential output conversion element L1, and the source is connected to the ground.

  Furthermore, the inverter 2 that inverts the transmission signal SD to be transmitted using the antenna AN1 and outputs the inverted signal to the gate of the transistor P1, and the signal output from the inverter 2 is converted into a time width tw of a pulse signal used for UWB communication, For example, a delay circuit 3 that delays by a half of 300 psec to 500 psec and outputs the delayed signal to the gate of the transistor N1 is provided. The delay circuit 3 is configured, for example, by connecting inverters 4, 5, and 6 in series, corresponds to a control unit, and delays the gate signal of the transistor N1 by the gate delay of the inverters 4, 5, and 6. Has been.

  For example, in a loop antenna using a transmission line having a short-circuited tip, the differential output conversion element L1 is not provided, and the antenna AN1 is directly between the connection point (point B) between the capacitor C1 and the transistor N1 and the ground. The structure interposed may be sufficient.

  Next, the operation of the wireless transmission circuit 1 configured as described above will be described. FIG. 2 is a timing chart showing operations of the inverter 2 and the delay circuit 3. First, when the transmission signal SD changes to high level, the gate signal G1 of the transistor P1 is set to low level by the inverter 2, and the transistor P1 is turned on (timing T1). Further, the gate signal G1 is further inverted three times by the inverters 4, 5, and 6 and delayed by a delay time d of, for example, 1 / 2tw, and is output to the gate of the transistor N1 as the gate signal G4 of the transistor N1, The transistor N1 is turned on with a delay of time d from the transistor P1 (timing T2).

  FIG. 3 is a timing chart showing the on / off timing of the transistors P1 and N1 and the timing of the current Iant flowing through the antenna AN1. First, at timing T1, when the transistor P1 is turned on while both the transistors P1 and N1 are turned off, a current flows into the point A by the transistor P1, and charging of the capacitor C1 is started. Then, as the capacitor C1 is charged, the potential at the point B increases, a transient current is supplied to the primary side of the differential output conversion element L1, and the primary current + IB of the differential output conversion element L1 flows. The antenna current Iant is supplied to the antenna AN1 from the secondary side of the differential output conversion element L1 according to the current + IB.

  Next, at timing T2, when the transistor N1 is turned on with a delay of time d from the transistor P1, the transient current supplied from the capacitor C1 to the differential output conversion element L1 is bypassed to the ground, and the potential at the point B decreases. The primary current + IB of the differential output conversion element L1 does not flow. Accordingly, the antenna current Iant of the antenna AN1 also stops flowing.

  As described above, since the antenna current Iant can flow through the antenna AN1 in a short pulse shape, a pulsed radio signal used for UWB communication can be radiated from the antenna AN1. Further, since the antenna current Iant can be made to flow in a short pulse shape for a time corresponding to the time width of the pulse signal used for UWB communication, current consumption for driving the antenna AN1 can be reduced.

  Further, the delay circuit 3 is configured to delay the gate signal of the transistor N1 by the gate delay time of the inverters 4, 5 and 6, so that the pulse used for the UWB communication is transmitted to the transistor N1 using a simple circuit. It can be turned on / off at a timing according to the time width of the signal.

  Next, when the transmission signal SD changes to a low level, the transistor P1 is turned off, and the charge charged in the capacitor C1 is discharged by the resistor R1. As a result, when the transmission signal SD newly changes to the high level, the capacitor C1 is charged again by the transistor P1, and the antenna current Iant can be made to flow through the antenna AN1 in a short pulse manner in the same manner as described above.

  In the wireless transmission circuit 1 shown in FIG. 1, while the transistor P1 is on, a direct current flows through the resistor R1, and current consumption increases. Therefore, for example, unlike the wireless transmission circuit 1a shown in FIG. 4, the resistor R1 is not provided, the drain of the transistor P1 is connected to the ground via the NMOS transistor N3 corresponding to the third switching element, and the gate of the transistor N3 In addition, the transistor P1 is turned off by supplying a signal obtained by delaying the gate signal of the transistor P1 by, for example, two inverters connected in series, and turning the transistor P1 and the transistor N3 on and off alternately. N3 may be turned on to discharge the charge charged in the capacitor C1.

  As a result, the transistor P1 and the transistor N3 are not turned on at the same time, current consumption by the resistor R1 is eliminated, and current consumption can be reduced.

  Note that the transistor N3 may be turned on only for a time necessary for discharging the capacitor C1, for example, after the transistor P1 is turned off, and is not limited to the configuration in which the transistor P1 and the transistor N3 are alternately turned on and off.

Further, as in the wireless transmission circuit 1a shown in FIG. 4, a power source V1 corresponding to a voltage application circuit is interposed between the primary side of the differential output conversion element L1 and the ground, and the source and drain of the transistor N1 are connected. The voltage Vds may be increased. Power supply output voltage V ₁ of the V1, for example about 10% of the antenna drive voltage VDD _1, for example, voltages V ₁ when the antenna drive voltage VDD ₁ is 3V may be 0.3V.

FIG. 5 is a diagram for explaining a change in the current IB depending on the presence or absence of the power supply V1. FIG. 5A is a diagram illustrating a waveform of the current IB when the transistor N1 is not turned on after the transistor P1 is turned on in the wireless transmission circuit 1a. When the transistor P1 is turned on, the current IB flows to the primary side of the differential output conversion element L1 via the capacitor C1, and the pulse width of the current IB becomes t1. Since the capacitor C1 direct current does not flow, the voltages V ₁ if fixed voltage, current IB does not depend on voltages V _1.

FIG. 5B is a diagram illustrating a waveform of the current IB when the transistor N1 is turned on after the transistor P1 is turned on. First, when turning on the transistor N1 after the transistor P1 was turned on in the wireless transmission circuit 1 is not provided with voltage V ₁ = 0, i.e. the power supply V1, the transistor N1 is to bypass current IB, FIGS. 5 (a) Compared to the case where the transistor N1 is not turned on, the pulse width of the current IB is shortened to t2.

Next, in FIG. 5B, when the voltage V ₁ > 0, that is, in the configuration of the wireless transmission circuit 1a provided with the power source V1, when the transistor P1 is turned on and then the transistor N1 is turned on, the voltage V ₁ is output as a differential output. Applied to the drain of the transistor N1 via the conversion element L1, the source-drain voltage Vds of the transistor N1 rises, and the current Ids drawn by the transistor N1 increases, so that the current compared to the case where the voltage V ₁ = 0. The pulse width of IB becomes short and becomes t3. Therefore, the relationship is t1>t2> t3.

  In this case, since the transistor N1 is a MOS transistor as shown in FIG. 6A, as shown in FIG. 6B, when the source-drain voltage Vds increases, the source-drain current Ids increases. . Therefore, by providing the power source V1 and increasing the source-drain voltage Vds, the current Ids drawn by the transistor N1 is increased, the pulse width of the current IB is shortened, and the pulse width of the antenna current Iant is shortened, thereby The width of the pulse signal emitted from AN1 can be shortened.

  Thereby, it becomes easy to adapt the pulse signal width radiated from the antenna AN1 to the time width of the pulse signal used in UWB communication, or a higher frequency band can be used as the frequency band used in UWB communication.

(Second Embodiment)
Next, a radio transmission circuit according to the second embodiment of the present invention will be described. FIG. 7 is a circuit diagram showing an example of the configuration of the wireless transmission circuit 1b according to the second embodiment of the present invention. The wireless transmission circuit 1b shown in FIG. 7 differs from the wireless transmission circuit 1 shown in FIG. 1 in the following points. That is, the wireless transmission circuit 1b shown in FIG. 7 is configured to be able to radiate positive and negative short pulse signals from the antenna AN1, and in addition to the wireless transmission circuit 1 shown in FIG. In the PMOS transistor P2 corresponding to the fifth switching element, the antenna driving voltage VDD ₂ is supplied to the source, and the drain is connected to the ground via the resistor R2.

  A connection point (point C) between the drain of the transistor P2 and the resistor R2 is connected to the drain of the transistor N1 via the capacitor C2 corresponding to the third capacitor and the primary side of the differential output conversion element L1. . The drain of the NMOS transistor N2 corresponding to the sixth switching element is connected to the connection point (point D) between the capacitor C2 and the differential output conversion element L1, and the source is connected to the ground.

  And the control part 7 is provided instead of the inverter 2 and the delay circuit 3 in the wireless transmission circuit 1 shown in FIG. The control unit 7 is configured by using, for example, a logic circuit, outputs gate signals of the transistors P1, P2, N1, and N2 according to the transmission signal SD, and turns on and off the transistors P1, P2, N1, and N2. To control.

  Since other configurations are the same as those of the wireless transmission circuit 1 shown in FIG. 1, the description thereof will be omitted, and the operation of the wireless transmission circuit 1b shown in FIG. 7 will be described below. FIG. 8 is a timing chart for explaining an example of the operation of the wireless transmission circuit 1b. First, when the control unit 7 accepts that the transmission signal SD has changed to the high level, the control unit 7 turns on the transistor N2, turns on the transistor P1, and turns on the transistor N1 with a delay time d. The As a result, in the same manner as the wireless transmission circuit 1 shown in FIG. 1, the antenna current Iant in the positive direction is caused to flow through the antenna AN1, and a positive short pulse signal is emitted from the antenna AN1.

  Next, the control unit 7 turns off the transistors N2, P1, and N1. Then, the control unit 7 turns on the transistor N1 and turns on the transistor P2. Then, a current flows into the point C by the transistor P2, charging of the capacitor C2 is started, and the potential at the point D increases with the charging of the capacitor C2. Then, since the point B is connected to the ground via the turned-on transistor N1, a transient current is supplied from the capacitor C2 to the primary side of the differential output conversion element L1, and the primary side of the differential output conversion element L1 A current -IB in the reverse direction flows as a current. In accordance with this current -IB, a current in the reverse direction is supplied as the antenna current Iant of the antenna AN1 from the secondary side of the differential output conversion element L1.

  Next, when the transistor N2 is turned on by the control unit 7 with a delay time d from the transistor P2, the reverse current supplied from the capacitor C2 to the differential output conversion element L1 is bypassed to the ground, The potential at the point D drops, and the primary side current -IB of the differential output conversion element L1 stops flowing. Accordingly, the antenna current Iant of the antenna AN1 also stops flowing.

  As described above, since the antenna drive circuit for supplying the pulse-like transient current is provided on both sides of the differential output conversion element L1, the antenna current Iant in the positive and negative directions is caused to flow in the pulse shape to the antenna AN1, and the antenna A short pulse signal of positive polarity and negative polarity can be radiated from AN1.

  Note that the control unit 7 may generate the delay time d by gate delay, similarly to the delay circuit 3 in the wireless transmission circuit 1a shown in FIG. Thereby, using a simple circuit, the transistors N1 and N2 can be turned on and off at a timing according to the time width of the pulse signal used for UWB communication.

  Further, similarly to the wireless transmission circuit 1a shown in FIG. 4, the capacitors C1 and C2 may be discharged using transistors instead of the resistors R1 and R2. As a result, current consumption by the resistors R1 and R2 is eliminated, and a reduction in current consumption can be achieved.

(Third embodiment)
Next, a radio transmission circuit according to the third embodiment of the present invention will be described. FIG. 9 is a circuit diagram showing an example of a configuration of a wireless transmission circuit 1c according to the third embodiment of the present invention. The wireless transmission circuit 1c shown in FIG. 9 differs from the wireless transmission circuit 1b shown in FIG. 7 in the following points. That is, the radio transmission circuit 1c shown in FIG. 9 is configured such that the pulse signal width radiated from the antenna AN1 in the radio transmission circuit 1b shown in FIG. 7 can be shortened, and the drain (point B) of the transistor N1. Is connected to the ground via the primary side of the differential output conversion element L1, the switch SW1, and the power source V1, and the drain (point D) of the transistor N2 is connected to the primary side of the differential output conversion element L1, the switch SW2, and It is connected to the ground via the power supply V2.

Thereby, when the switches SW1 and SW2 are turned on, the source-drain voltages of the transistors N1 and N2 are raised by the power sources V1 and V2, respectively. Power V1, voltage V _1, V ₂ of V2, the voltage V _1, V ₂ in each case for example the antenna drive voltage VDD _1, VDD ₂ is 3V may be 0.3V.

  Since the other configuration is the same as that of the wireless transmission circuit 1b shown in FIG. 7, the description thereof will be omitted, and the operation of the wireless transmission circuit 1c shown in FIG. 9 will be described below. FIG. 10 is a timing chart for explaining an example of the operation of the wireless transmission circuit 1c. First, when the control unit 7a accepts that the transmission signal SD has changed to a high level, the control unit 7a turns on the switch SW1 and raises the drain voltage of the transistor N1. Next, the transistor P1 is turned on, and the transistor N1 is turned on after a delay time d. Accordingly, in the same manner as the wireless transmission circuit 1b shown in FIG. 7, the antenna current Iant in the positive direction flows through the antenna AN1 in a pulse shape, and a positive short pulse signal is radiated from the antenna AN1.

  In this case, since the source-drain voltage Vds is increased by increasing the drain voltage of the transistor N1, the source-drain current Ids of the transistor N1 is increased in the same manner as described above, and the current drawn by the transistor N1 is increased. Ids increases, the pulse width of the current + IB is shortened, and the pulse width of the antenna current Iant is shortened. As a result, the positive pulse signal width radiated from the antenna AN1 can be shortened.

  Next, the switch 7 and the transistors P1 and N1 are turned off by the controller 7a. Then, the switch 7 is turned on by the controller 7a, and the drain voltage of the transistor N2 is increased. Next, the transistor P2 is turned on, and the transistor N2 is turned on after a delay time d. As a result, the antenna current Iant in the reverse direction flows through the antenna AN1 in the same manner as the radio transmission circuit 1b shown in FIG. 7, and a negative short pulse signal is radiated from the antenna AN1.

  In this case, since the source-drain voltage Vds is increased by increasing the drain voltage of the transistor N2, the source-drain current Ids of the transistor N2 is increased in the same manner as described above, and the current drawn by the transistor N2 is increased. Ids increases, the pulse width of the current -IB is shortened, and the pulse width of the antenna current Iant is shortened. As a result, the negative pulse signal width radiated from the antenna AN1 can be shortened. This makes it easy to adapt the positive and negative pulse signal widths radiated from the antenna AN1 to the time width of the pulse signal used in UWB communication, or a higher frequency band as the frequency band used in UWB communication. Can be used.

  Note that, as in the wireless transmission circuit 1d illustrated in FIG. 11, the connection destination of the source of the transistor N2 can be switched to either the ground or the power supply V1 by the switch SW1, and the connection destination of the drain of the transistor N1 is switched to the ground and the switch SW2. It is good also as a structure which can be switched to either of the power supplies V2. In this case, as shown in parentheses in the switches SW1 and SW2 in the timing chart shown in FIG. 10, instead of turning on the switches SW1 and SW2, they are switched to the power sources V1 and V2, respectively, and instead of turning off the switches SW1 and SW2, the ground By switching to the side, the same operation as the wireless transmission circuit 1c shown in FIG. 9 can be performed.

(Fourth embodiment)
Next, a radio transmission circuit according to the fourth embodiment of the present invention will be described. In the wireless transmission circuit 1b shown in FIG. 7, in the wireless transmission circuit according to the fourth embodiment, the control unit 7 switches, for example, the voltage values of the antenna driving voltages VDD ₁ and VDD ₂ according to the transmission signal SD. The pulse signal radiated from the antenna AN1 is subjected to amplitude modulation.

  Since the other configuration is the same as that of the wireless transmission circuit 1b shown in FIG. 7, the description thereof will be omitted, and the operation of the wireless transmission circuit according to the present embodiment will be described below. FIG. 12A is a diagram illustrating an example of a waveform of the antenna current Iant that flows through the antenna AN1 in accordance with the logical value of the transmission signal SD in the wireless transmission circuit 1b illustrated in FIG. In FIG. 12A, the antenna current Iant in the positive and negative directions is caused to flow through the antenna AN1 in accordance with the logical values “0” and “1”, respectively, and the positive and negative pulse signals are respectively sent from the antenna AN1. Shows an example in which is emitted.

  On the other hand, FIG. 12B is a diagram illustrating an example of a waveform of the antenna current Iant that flows in the antenna AN1 in accordance with the logical value in the transmission signal SD in the wireless transmission circuit according to the present embodiment. In the wireless transmission circuit according to the fourth embodiment, the control unit 7 controls the antenna current Iant according to the bit pattern for every 2 bits in the transmission signal SD.

That is, in FIG. 12B, for the bit patterns “00” and “01”, the antennas in the positive and negative directions respectively according to “00” and “01”, as in the case of the wireless transmission circuit 1b. The current Iant is passed through the antenna AN1 in a pulsed manner, and positive and negative pulse signals are radiated from the antenna AN1, respectively. Furthermore, for the bit patterns “10” and “11”, the control unit 7 increases the antenna drive voltages VDD ₁ and VDD ₂ in a state where the values are positive according to “10” and “11”, respectively. The antenna current Iant in the negative direction is caused to flow through the antenna AN1, and the current value of the antenna current Iant is increased. Thereby, the amplitude of the pulse signal radiated from the antenna AN1 corresponding to the bit patterns “10” and “11” is increased more than the amplitude of the pulse signal corresponding to the bit patterns “00” and “01”. The pulse signal radiated from the antenna AN1 can be amplitude-modulated. Thereby, twice the amount of information can be expressed with the same number of pulses, and the transmission speed can be improved.

(Fifth embodiment)
Next, a radio transmission circuit according to a fifth embodiment of the present invention will be described. FIG. 13 is a circuit diagram showing an example of the configuration of a wireless transmission circuit 1e according to the fifth embodiment of the present invention. The wireless transmission circuit 1e shown in FIG. 13 is different from the wireless transmission circuit 1a shown in FIG. 4 in the following points. That is, the wireless transmission circuit 1e shown in FIG. 13 is configured to radiate a Gaussian pulse as a pulse signal from the antenna AN1, and is a PMOS transistor corresponding to the fourth switching element in which the antenna driving voltage VDD ₁ is supplied to the source. P3 is further provided, and the drain of the transistor P3 is connected to the differential output conversion element L1 via a capacitor C3 corresponding to a second capacitor.

Further, the drain voltage of the transistor N3, that is, the drain voltage of the transistor P1 (the voltage at the point A) is fed back to the gate voltage of the transistor N3 by the feedback circuit 8 configured using, for example, a differential amplifier, and the drain voltage of the transistor P1 (voltage at point a) lower voltage V3 than the voltage VDD _1, is for example, fixed at a half voltage voltage VDD ₁ 1.5V. In place of the inverter 2 and the delay circuit 3, a control unit 7c for controlling on and off of the transistors P1, P3, and N1 is provided.

  Since the other configuration is the same as that of the wireless transmission circuit 1a shown in FIG. 4, the description thereof will be omitted, and the operation of the wireless transmission circuit 1e shown in FIG. 13 will be described below. FIG. 14A is a diagram for explaining the operation of the wireless transmission circuit 1e. First, the transistor P1 is turned on by the controller 7c (timing T1), charging of the capacitor C1 is started, a current + IB flows through the differential output conversion element L1, and an antenna current Iant flows through the antenna AN1.

Next, when the pulse width of the Gaussian pulse to be radiated from the antenna AN1, for example, is tw, the control unit 7c turns on the transistor N1 with a delay of, for example, 1/4 tw from the timing T1, bypassing the current + IB, As the antenna current Iant decreases, the voltage at point B decreases (timing T2). When the voltage at point B is below the voltage V _1, reverse current flows in the differential output converter L1 from the power source V1, it flows negative antenna current Iant the antenna AN1.

  Next, the control unit 7c turns on the transistor P3 with a delay of, for example, 1/4 tw from the timing T2 (timing T3), starts charging the capacitor C3, and reversely flows in the differential output conversion element L1. Decreases, and the antenna current Iant flowing through the antenna AN1 returns to zero. In this way, the Gaussian pulse shown in FIG. 14A can be radiated from the antenna.

  FIG. 14B is defined by the characteristics of the impulse signal pulse radiated from the antenna AN1 in the wireless transmission circuit 1a shown in FIG. 4, the characteristics of the Gaussian pulse shown in FIG. 14A, and the UWB standard. It is a graph which shows the characteristic of the pulse signal which is. As shown in FIG. 14B, the Gaussian pulse approximates the characteristics of the pulse signal defined by the UWB standard, and a good signal pulse can be obtained rather than the impulse signal pulse.

  As shown in FIG. 15, the wireless transmission circuit 1c shown in FIG. 9 includes transistors P3 and P4 similar to the wireless transmission circuit 1e shown in FIG. 13, capacitors C3 and C4, and feedback circuits 8 and 9. It is good also as a structure. As a result, Gaussian pulses having positive and negative polarities can be radiated from the antenna AN1.

  Moreover, although the example which uses the radio | wireless transmission circuit concerning this invention for UWB communication was shown, if it is a radio | wireless communication system which communicates not only using UWB communication but using a pulse, the radio transmission circuit concerning this invention is applied. be able to.

1 is a circuit diagram showing an example of a configuration of a wireless transmission circuit according to a first embodiment of the present invention. 2 is a timing chart illustrating operations of the inverter and the delay circuit illustrated in FIG. 1. 3 is a timing chart for explaining the operation of the wireless transmission circuit shown in FIG. 1. FIG. 4 is a circuit diagram showing another example of the configuration of the wireless transmission circuit according to the first embodiment of the present invention. FIG. 5 is an explanatory diagram for explaining an operation of the wireless transmission circuit shown in FIG. 4. FIG. 5 is an explanatory diagram for explaining an operation of the wireless transmission circuit shown in FIG. 4. It is a circuit diagram which shows an example of a structure of the wireless transmission circuit which concerns on the 2nd Embodiment of this invention. 8 is a timing chart for explaining an example of the operation of the wireless transmission circuit shown in FIG. 7. It is a circuit diagram which shows an example of a structure of the radio | wireless transmission circuit which concerns on the 3rd Embodiment of this invention. 10 is a timing chart for explaining an example of the operation of the wireless transmission circuit shown in FIG. 9. It is a circuit diagram which shows another example of a structure of the wireless transmission circuit which concerns on the 3rd Embodiment of this invention. It is a figure for demonstrating operation | movement of the radio | wireless transmission circuit which concerns on the 4th Embodiment of this invention. It is a circuit diagram which shows an example of a structure of the wireless transmission circuit which concerns on the 5th Embodiment of this invention. It is a figure for demonstrating operation | movement of the radio | wireless transmission circuit shown in FIG. It is a circuit diagram which shows another example of a structure of the radio | wireless transmission circuit which concerns on the 5th Embodiment of this invention. It is a circuit diagram which shows the radio | wireless transmission circuit used for UWB communication based on background art. It is explanatory drawing for demonstrating an example of operation | movement of the radio | wireless transmission circuit shown in FIG.

Explanation of symbols

1, 1a, 1b, 1c, 1d, 1e Wireless transmission circuit 2 Inverter 3 Delay circuit 4, 5, 6 Inverter 7, 7a, 7b, 7c Control unit 8, 9 Feedback circuit AN1 Antenna C1, C2, C3, C4 Capacitor P1 , P2, P3, P4 Transistors N1, N2, N3 Transistors R1, R2 Resistor SD Transmission signal SW1, SW2 Switches V1, V2 Power supply

Claims (9)

A wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using a pulse,
A series circuit of a first switching element, a first capacitor, and the antenna connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground;
A second switching element connected between a connection point of the first capacitor and the antenna and a ground, and being turned on to bypass a transient current supplied from the first capacitor to the antenna; ,
The transmission signal a signal Ru is turned on the first switching device so as to emit a positive pulse from the antenna according to the first delay time only by delaying the second corresponding to the time width of the pulse And a delay unit that turns on the second switching element with a delay of a first delay time from the first switching element by supplying the switching element to the switching element . A wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using a pulse,
  A transformer having the antenna connected to the secondary side;
  A series circuit of a first switching element, a first capacitor, and a primary side of the transformer connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground;
  Connected between a connection point between the first capacitor and the primary side of the transformer and the ground, and is turned on to bypass a transient current supplied from the first capacitor to the primary side of the transformer. A second switching element;
  A signal for turning on the first switching element to emit a positive pulse from the antenna in response to the transmission signal is delayed by a first delay time corresponding to the time width of the pulse, and the second switching element is delayed. A wireless transmission circuit comprising: a delay unit that turns on the second switching element with a delay of a first delay time from the first switching element by supplying the switching element.   The second switching element is a MOS transistor;
  A voltage application circuit for increasing a source-drain voltage of the MOS transistor;
  The radio transmission circuit according to claim 1, wherein the MOS transistor bypasses the transient current by a source-drain current.   A third switching element that discharges the first capacitor when turned on;
  The wireless transmission circuit according to claim 1, wherein the control unit turns on the third switching element after turning off the first switching element.   The first switching element is interposed between the first power supply unit and the first capacitor,
  The wireless transmission circuit according to claim 1, wherein the control unit changes the antenna driving voltage in accordance with the transmission signal.   The second switching element bypasses a transient current supplied from the first capacitor to the antenna when turned on, and supplies a current in a direction opposite to the transient current to the antenna.
  A fourth switching element that, when turned on, supplies a transient current in the same direction as the transient current to the antenna via a second capacitor;
  The control unit turns on the first switching element according to the transmission signal, turns on the second switching element by delaying by the first delay time, and further according to the time width of the pulse 6. The radio transmission circuit according to claim 1, wherein the fourth switching element is turned on with a delay of a second delay time. 6.   The wireless transmission circuit according to claim 1, wherein the control unit generates the delay time using a gate delay.   A wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using a pulse,
  A series circuit of a first switching element, a first capacitor, and the antenna connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground;
  A second switching element connected between a connection point of the first capacitor and the antenna and a ground, and being turned on to bypass a transient current supplied from the first capacitor to the antenna; ,
  A third capacitor having one end connected to the terminal of the antenna on the opposite side across the antenna as viewed from the connection point of the first capacitor and the antenna;
  The first capacitor is connected between the second power supply section for supplying a predetermined antenna driving voltage and the other end of the third capacitor and is turned on to the antenna via the third capacitor. A fifth switching element for supplying a transient current in a direction opposite to the transient current supplied to the antenna from
  A sixth point is connected between the connection point of the antenna and the other end of the third capacitor and the ground, and is turned on to bypass a transient current supplied from the third capacitor to the antenna. A switching element;
  When a positive pulse is radiated from the antenna according to the transmission signal, the second switching element and the fifth switching element are turned off, and the first switching element and the sixth switching element are turned off. When the second switching element is turned on after being delayed by the first delay time to emit a negative pulse from the antenna, the first switching element and the sixth A controller that turns off the switching element, turns on the second switching element and the fifth switching element, and then turns on the sixth switching element by delaying by the first delay time; thing
  A wireless transmission circuit.   A wireless transmission circuit that causes an antenna current corresponding to a transmission signal to flow to an antenna provided outside for wireless communication that performs communication using a pulse,
  A transformer having the antenna connected to the secondary side;
  A series circuit of a first switching element, a first capacitor, and a primary side of the transformer connected between a first power supply unit that supplies a predetermined antenna driving voltage and the ground;
  Connected between a connection point between the first capacitor and the primary side of the transformer and the ground, and is turned on to bypass a transient current supplied from the first capacitor to the primary side of the transformer. A second switching element;
  A third capacitor having one end connected to a primary side terminal of the transformer on the opposite side across the transformer as seen from a connection point between the first capacitor and the primary side of the transformer;
  The first capacitor is connected between the second power supply unit for supplying a predetermined antenna driving voltage and the other end of the third capacitor, and is turned on to the transformer via the third capacitor. A fifth switching element for supplying a transient current in a direction opposite to the transient current supplied from
  A transient current that is connected between a connection point between the primary side of the transformer and the other end of the third capacitor and the ground and is turned on to be supplied from the third capacitor to the primary side of the transformer. A sixth switching element that bypasses
  When a positive pulse is radiated from the antenna according to the transmission signal, the second switching element and the fifth switching element are turned off, and the first switching element and the sixth switching element are turned off. When the second switching element is turned on after being delayed by the first delay time and a negative pulse is radiated from the antenna, the first switching element and the sixth A controller that turns off the switching element, turns on the second switching element and the fifth switching element, and then turns on the sixth switching element by delaying by the first delay time;
  A wireless transmission circuit comprising:

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