JP6915312B2 - Wireless communication device - Google Patents

Description

The present invention relates to a wireless communication device, and more particularly to a wireless communication device that controls transmission power by current control.

As a method for controlling the transmission power of a wireless communication device, a current control method for keeping the current of an amplifier constant is known. Further, Patent Document 1 discloses, regarding a current control method, a technique of providing a Zener diode for overvoltage limitation between _{an output power control terminal (VAPC} ) and an amplifier input in preparation for an overvoltage such as an abnormal load. ing. This Zener diode limits the power control voltage input to the amplifier in the event of an overvoltage such as an abnormal load. As a result, in Patent Document 1, a predetermined derating of the amplifier can be secured.

Japanese Unexamined Patent Publication No. 8-242128

However, in the technique disclosed in Patent Document 1, since the voltage limit by the Zener diode is a fixed voltage, the upper limit of the power control voltage due to an abnormal load or the like is the same fixed voltage under all conditions. Therefore, there is a problem that the temperature protection of the amplifier must be set under the strictest derating condition.

The present invention has been made to solve such a problem, and it is possible to appropriately set the derating of the amplifier under an abnormal load without affecting the output characteristics under a normal load. The purpose is to provide a communication device.

Therefore, the present invention compares an amplifier that amplifies an input signal based on a power control voltage, a current detection unit that detects a current flowing through the amplifier, and a voltage corresponding to the current and a reference voltage, and obtains a comparison result. A power control voltage generator that generates the power control voltage based on the power control voltage, a temperature detector that detects the temperature of the amplifier, a variable regulator that can change the power supply voltage supplied to the power control voltage generator, and the temperature. Based on this, the present invention provides a wireless communication device including a control unit that controls the power supply voltage supplied from the variable regulator to the power control voltage generation unit.

Further, the present invention compares an amplifier that amplifies an input signal based on a power control voltage, a current detection unit that detects a current flowing through the amplifier, and a voltage corresponding to the current and a reference voltage, and obtains a comparison result. A power control voltage generator that generates the power control voltage based on the power control voltage, a variable regulator that can change the power supply voltage supplied to the power control voltage generator, and the power control from the variable regulator based on the frequency of the input signal. Provided is a wireless communication device including a control unit that controls the power supply voltage supplied to the voltage generation unit.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a wireless communication device capable of appropriately setting the derating of an amplifier under an abnormal load without affecting the output characteristics under a normal load.

It is a block diagram which shows the structural example of the wireless communication device which concerns on Embodiment 1. FIG. It is a graph which shows the power control voltage at the time of a normal load and an abnormal load at a normal temperature of the wireless communication device which concerns on Embodiment 1. FIG. It is a graph which shows the power control voltage at the time of a normal load and an abnormal load at a high temperature of the wireless communication device which concerns on Embodiment 1. FIG. It is a flowchart which shows the processing example at the time of an abnormal load in the wireless communication device which concerns on Embodiment 1. FIG. It is a block diagram which shows the structural example of the wireless communication device which concerns on Embodiment 2. FIG. It is a graph which shows the power control voltage at the time of a normal load and an abnormal load at a normal temperature of the wireless communication device which concerns on Embodiment 2. FIG. It is a graph which shows the power control voltage at the time of a normal load and an abnormal load at a high temperature of the wireless communication device which concerns on Embodiment 2. FIG. It is a block diagram which shows the structural example of the wireless communication device which concerns on Embodiment 3. FIG. It is a block diagram which shows the structural example of the wireless communication device which concerns on Embodiment 4. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding elements are designated by the same reference numerals, and duplicate explanations are omitted as necessary for the sake of clarification of the explanations.

Embodiment 1
First, a configuration example of the wireless communication device 100 according to the first embodiment of the present invention will be described with reference to the block diagram of FIG. The wireless communication device 100 includes an amplifier 10, a power supply 20, a current detection unit 30, a temperature detection unit 40, a control unit 50, a variable regulator 60, and a power control voltage generation unit 70.

The amplifier 10 receives the power control voltage from the power control voltage generation unit 70. Further, the amplifier 10 amplifies the input signal based on the received power control voltage. Then, the amplifier 10 outputs the amplified signal as an output signal. The amplifier 10 is, for example, a high-frequency power amplifier at the final stage of the transmitter in the wireless communication device 100. Further, the amplifier 10 is composed of, for example, a FET (Field Effect Transistor).

The power supply 20 is a power supply that supplies electric power to the amplifier 10 via the current detection unit 30. The power source 20 is, for example, the battery of the wireless communication device 100.

The current detection unit 30 detects the current flowing through the amplifier 10. The current detection unit 30 is arranged between the power supply 20 and the amplifier 10. The current detection unit 30 detects the current flowing through the amplifier 10 by detecting, for example, the voltage across a resistor connected in series between the power supply 20 and the amplifier 10. Then, the current detection unit 30 outputs the detected current value to the power control voltage generation unit 70.

The temperature detection unit 40 is arranged in the vicinity of the amplifier 10 and detects the temperature of the amplifier 10. Then, the temperature detection unit 40 outputs the detected temperature to the control unit 50. The temperature detection unit 40 is composed of, for example, a thermistor.

The variable regulator 60 can change the power supply voltage supplied to the power control voltage generation unit 70. The variable regulator 60 can also turn off the output.

The control unit 50 receives the temperature of the amplifier 10 from the temperature detection unit 40. Then, the control unit 50 controls the power supply voltage supplied from the variable regulator 60 to the power control voltage generation unit 70 based on the temperature of the received amplifier 10. The control unit 50 is composed of, for example, a CPU (Central Processing Unit).

In the power control voltage generation unit 70, the upper limit value of the power control voltage is changed by changing the power supply voltage of the power control voltage generation unit 70 supplied from the variable regulator 60. Further, the power control voltage generation unit 70 receives a current value from the current detection unit 30. Further, the power control voltage generation unit 70 compares the voltage corresponding to the received current value with the reference voltage, and generates the power control voltage based on the comparison result. Here, the reference voltage is a voltage for setting the output power of the amplifier 10 to a predetermined output power. Then, the power control voltage generation unit 70 outputs the generated power control voltage to the amplifier 10. The amplifier 10 amplifies the input signal based on the received power control voltage and outputs it to the antenna of the wireless communication device 100. The power control voltage is controlled so that the current flowing through the amplifier 10 is kept constant even if the impedance of the antenna changes within a predetermined range, but the upper limit of the control voltage is the power supplied from the variable regulator 60. It is determined by the power supply voltage of the control voltage generation unit 70.

Subsequently, the power control voltage generated by the power control voltage generation unit 70 will be described with reference to the graphs of FIGS. 2 and 3.

FIG. 2 is a graph showing the power control voltage at normal load and abnormal load at room temperature. Here, the abnormal load is a state in which the impedance of the antenna, which is the load of the amplifier 10, fluctuates greatly due to, for example, the antenna of the wireless communication device 100 being touched by a human hand or a metal plate, resulting in an abnormality. Indicates that.

The normal temperature, power supply voltage supplied to the power control voltage generator 70 is controlled to V _NT. Accordingly, the upper limit value of the power control voltage at the normal temperature is set to V _NT. The V _NT may be referred to as a first voltage.

In normal temperature and normal load, the power control voltage generator 70, the power control voltage is controlled by V _NT smaller value by the reference voltage. In addition, when an abnormal load occurs, the reference voltage cannot be used for control, and when transmission is started, the power control voltage _{rises to VNT} at once.

FIG. 3 is a graph showing the power control voltage at the time of normal load and abnormal load at high temperature. The normal temperature and the high temperature are separated by a predetermined threshold value. That is, room temperature is a temperature equal to or lower than a predetermined threshold value, and high temperature is a temperature higher than a predetermined threshold value.

At high temperatures, the power supply voltage supplied to the power control voltage generation unit 70 is controlled by the _VHT. As a result, the upper limit of the power control voltage at high temperature is set to _{VHT. Here, V HT} is the voltage lower than _{V NT.} The _VHT may be referred to as a second voltage.

At high temperature and under normal load, the power control voltage generator 70 controls the power control voltage with a value smaller than _{VHT by the reference voltage.} Further, at the time of abnormal load, the control by the reference voltage cannot be performed, and when the transmission is started, the power control voltage _{rises to VHT} at once.

Subsequently, an example of processing at the time of an abnormal load in the wireless communication device 100 will be described with reference to the flowchart of FIG.

First, the temperature detection unit 40 detects the temperature of the amplifier 10 (step S1). Next, the control unit 50 determines whether or not the detected temperature is higher than a predetermined threshold value (step S2).

If the detected temperature is below a predetermined threshold value (NO in step S2), the control unit 50 controls the output of the variable regulator 60 _{V NT} (step S3). Next, the reference voltage of the power control voltage generation unit 70 is set (step S4). Next, the power control voltage generator 70 sets the power control voltage _{V NT} (step S5). Next, the amplifier 10 outputs the transmission power (step S6). After step S6, the process returns to step S1.

On the other hand, when the detected temperature is higher than a predetermined threshold value (YES in step S2), the control unit 50 controls the output of the variable regulator 60 to _VHT (step S7). Next, the reference voltage of the power control voltage generation unit 70 is set (step S8). Next, the power control voltage generation unit 70 sets the power control voltage to _VHT (step S9). Then, the amplifier 10 outputs the transmission power (step S6). After step S6, the process returns to step S1.

As described above, in the wireless communication device 100 according to the first embodiment of the present invention, the variable regulator 60 capable of changing the power supply voltage supplied to the power control voltage generation unit 70 and the temperature detected by the temperature detection unit 40 are used. Based on this, the configuration includes a control unit 50 that controls the power supply voltage supplied from the variable regulator 60 to the power control voltage generation unit 70. As a result, in the wireless communication device 100 according to the first embodiment, the upper limit value of the power control voltage can be controlled based on the temperature of the amplifier 10. Therefore, in the wireless communication device 100, the derating of the amplifier 10 at the time of abnormal load can be appropriately set without changing the transmission power at the time of normal load and the resolution of current detection. That is, the derating of the amplifier at the time of abnormal load can be appropriately set without affecting the output characteristics at the time of normal load.

Further, the wireless communication device 100 has a configuration in which the control unit 50 compares the temperature detected by the temperature detection unit 40 with a predetermined threshold value. Further, in the wireless communication device 100, when the temperature is equal to or lower than a predetermined threshold value, the control unit 50 controls the power supply voltage supplied to the power control voltage generation unit 70 to _VT , and the temperature exceeds the predetermined threshold value. when high, has a configuration for controlling the power supply voltage to V _HT is lower than V _NT voltage. As a result, in the wireless communication device 100, the upper limit value of the power control voltage at room temperature can be set higher than the upper limit value of the power control voltage at high temperature.

Further, the wireless communication device 100 has a configuration in which the output of the variable regulator 60 can be turned off. Thereby, when the transmission by the wireless communication device 100 is turned off, the output of the variable regulator 60 can be turned off. That is, when the transmission by the wireless communication device 100 is turned off, the input of the power control voltage to the amplifier 10 can be cut.

Embodiment 2
Subsequently, a configuration example of the wireless communication device 200 according to the second embodiment of the present invention will be described with reference to the block diagram of FIG. The wireless communication device 200 according to the second embodiment is a specific example of the wireless communication device 100 according to the first embodiment. The wireless communication device 200 includes an amplifier 10, a power supply 20, a current detection unit 30, a temperature detection unit 40, a control unit 50, a variable regulator 60, and a power control voltage generation unit 70A.

The power control voltage generation unit 70A includes a comparator 71 and an active filter 72.

The comparator 71 receives a current value from the current detection unit 30. Further, the comparator 71 receives a reference voltage. Further, the comparator 71 compares the voltage corresponding to the received current value with the reference voltage, and outputs the comparison result to the active filter 72. The comparator 71 is composed of, for example, an operational amplifier. Further, since the reference voltage input to the comparator is configured to include the active filter 72 in the subsequent stage, the waveform is close to a square wave, the band is limited by the characteristics of the active filter 72, and the waveform becomes smooth. Further, since the active filter 72 causes a time delay, the rise and fall are faster than in the first embodiment.

The power supply voltage of the active filter 72 is supplied from the variable regulator 60. In the active filter 72, the upper limit value of the power control voltage is changed by changing the power supply voltage supplied from the variable regulator 60. Further, the active filter 72 receives the comparison result from the comparator 71. Further, the active filter 72 generates a power control voltage based on the received comparison result. Then, the active filter 72 outputs the generated power control voltage to the amplifier 10. The active filter 72 is, for example, a vessel type or the like multiple feedback type filter, and is composed of an operational amplifier.

Subsequently, the power control voltage generated by the power control voltage generation unit 70A will be described with reference to the graphs of FIGS. 6 and 7.

FIG. 6 is a graph showing the power control voltage at normal load and abnormal load at room temperature. The normal temperature, power supply voltage supplied to the active filter 72 is controlled to V _NT. Accordingly, the upper limit value of the power control voltage at the normal temperature is set to V _NT.

In normal temperature and normal load, the power control voltage generator 70A, a power control voltage is controlled by V _NT smaller value by the reference voltage. In addition, when an abnormal load occurs, the reference voltage cannot be used for control, and when transmission is started, the power control voltage rises to _VN.

FIG. 7 is a graph showing the power control voltage at the time of normal load and at the time of abnormal load at high temperature. At high temperatures, the power supply voltage supplied to the active filter 72 is controlled by the _VHT. As a result, the upper limit of the power control voltage at high temperature is set to _VHT.

At a high temperature, in the normal load, the power control voltage generator 70A, a power control voltage is controlled by V _HT value less than the reference voltage. Further, at the time of abnormal load, the control by the reference voltage cannot be performed, and when the transmission is started, the power control voltage rises to _VHT.

In FIGS. 6 and 7, the rise and fall of the power control voltage at the time of an abnormal load have smooth transient response characteristics similar to those at the time of a normal load due to the transfer function of the active filter 72. This makes it possible to limit the frequency band in the rising and falling envelopes of the power control voltage at the time of abnormal load.

As described above, in the wireless communication device 200 according to the second embodiment of the present invention, the power control voltage generation unit 70A is configured to include the comparator 71 and the active filter 72. Further, in the wireless communication device 200, the power supply voltage of the active filter 72 is supplied from the variable regulator 60. As a result, the wireless communication device 200 can achieve the same effect as the wireless communication device 100 of the first embodiment.

Further, in the wireless communication device 200, the active filter 72 is configured to be a multiple feedback type filter. As a result, in the wireless communication device 200, it is possible to limit the frequency band in the envelope of rising and falling power control voltage at the time of abnormal load. That is, unnecessary radiation in the rising and falling envelopes of the power control voltage at the time of an abnormal load can be suppressed.

Embodiment 3
Subsequently, a configuration example of the wireless communication device 300 according to the third embodiment of the present invention will be described with reference to the block diagram of FIG. The wireless communication device 300 according to the third embodiment is a specific example of the wireless communication device 100 according to the first embodiment. The wireless communication device 300 includes an amplifier 10, a power supply 20, a current detection unit 30, a temperature detection unit 40, a control unit 50, a variable regulator 60, and a power control voltage generation unit 70B.

The power control voltage generation unit 70B includes a comparator 71 and a passive filter 73.

The power supply voltage of the comparator 71 is supplied from the variable regulator 60. In the comparator 71, the upper limit value of the power control voltage is changed by changing the power supply voltage supplied from the variable regulator 60.

The passive filter 73 receives the comparison result from the comparator 71. Further, the passive filter 73 generates a power control voltage based on the received comparison result. Specifically, the passive filter 73 generates a power control voltage by integrating the received comparison results. Then, the passive filter 73 outputs the generated power control voltage to the amplifier 10. The passive filter 73 is, for example, a CR filter having a capacitor and a resistor.

The power control voltage generated by the power control voltage generation unit 70B is the same as the power control voltage shown in FIGS. 2 and 3, and description and illustration thereof will be omitted.

As described above, in the wireless communication device 300 according to the third embodiment of the present invention, the power control voltage generation unit 70B is configured to include the comparator 71 and the passive filter 73. Further, in the wireless communication device 300, the power supply voltage of the comparator 71 is supplied from the variable regulator 60. As a result, the wireless communication device 300 can achieve the same effect as the wireless communication device 100 of the first embodiment.

Further, in the wireless communication device 300, the power control voltage generation unit 70B is configured to include a passive filter 73 instead of the active filter 72. As a result, the wireless communication device 300 can reduce power consumption and cost as compared with the wireless communication device 200 of the second embodiment.

Embodiment 4
Subsequently, a configuration example of the wireless communication device 400 according to the fourth embodiment of the present invention will be described with reference to the block diagram of FIG. The wireless communication device 400 according to the fourth embodiment is a modification of the wireless communication device 100 according to the first embodiment. The wireless communication device 400 includes an amplifier 10, a power supply 20, a current detection unit 30, a temperature detection unit 40, a control unit 50A, a variable regulator 60, a power control voltage generation unit 70, and a directional coupler 80. , A detection circuit 90, and an antenna 1.

The antenna 1 transmits a signal received from the amplifier 10 via the directional coupler 80 to another device. Further, the antenna 1 outputs a signal received from another device to a receiving circuit (not shown) of the wireless communication device 400.

A part of the signal output from the amplifier 10 to the antenna 1 via the directional coupler 80 is reflected at the connection point 2 between the directional coupler 80 and the antenna 1. The directional coupler 80 outputs the reflected signal reflected at the connection point 2 to the detection circuit 90.

The detection circuit 90 detects the power of the received reflected signal. Then, the detection circuit 90 outputs the electric power of the detected reflected signal to the control unit 50A.

The control unit 50A receives the power of the reflected signal from the detection circuit 90. Further, the control unit 50A receives the temperature of the amplifier 10 from the temperature detection unit 40. Then, the control unit 50A controls the power supply voltage supplied from the variable regulator 60 to the power control voltage generation unit 70 based on the temperature of the received amplifier 10 and the electric power of the reflected signal. For example, the control unit 50A determines whether or not the amplifier 10 has an abnormal load based on the power of the reflected signal, and is supplied to the power control voltage generation unit 70 depending on whether the amplifier 10 has an abnormal load or not. The power supply voltage may be controlled differently. The determination of whether or not the load is abnormal may be determined by determining that the load is abnormal when the power of the reflected signal is greater than the threshold value and determining that the load is normal when the power of the reflected signal is equal to or less than the threshold value.

Further, the control unit 50A may start the processing at the time of the abnormal load, for example, when the load is abnormal. The process shown in FIG. 4 may be performed as the process at the time of this abnormal load.

Further, the control unit 50A may use the frequency characteristic of the amplifier 10 as a parameter when controlling the power supply voltage supplied to the power control voltage generation unit 70. That is, the frequency characteristics are various characteristics of the amplifier 10 with respect to the frequency of the input signal, for example, the frequency characteristics of the gain and efficiency of the amplifier 10. The wireless communication device 400 includes an oscillator (not shown), and the transmission frequency and reception frequency used in communication are determined based on the oscillation frequency of the oscillator. The frequency of the input signal corresponds to the transmission frequency in this case. There is no particular difficulty in obtaining the frequency setting information of the input signal by the control unit 50A, and the control unit 50A has a configuration for obtaining the setting information of the oscillation frequency to the oscillator, or the control unit 50A has a configuration. The setting information of the oscillation frequency may be given to the oscillator.

In the embodiment, control is performed to keep the current flowing through the amplifier 10 constant, but the power control voltage for keeping the current value constant may differ depending on the frequency depending on the frequency characteristics of the amplifier 10. Further, it may be desired to set the current flowing through the amplifier 10 to be different depending on the frequency. The control unit 50A controls the power supply voltage supplied to the power control voltage generation unit 70 according to the frequency in order to take measures according to those frequencies, without affecting the output characteristics under normal load. The derating of the amplifier at the time of abnormal load can be set appropriately.

The control unit 50A may control the power supply voltage supplied to the power control voltage generation unit 70 based on the temperature of the amplifier 10 and the frequency characteristics of the amplifier 10. This makes it possible to appropriately set the derating according to the temperature and frequency.

As described above, the wireless communication device 400 according to the fourth embodiment of the present invention has a configuration including a directional coupler 80 and a detection circuit 90. Further, in the wireless communication device 400, the control unit 50A is configured to control the power supply voltage supplied to the power control voltage generation unit 70 based on the temperature of the amplifier 10 and the power of the reflected signal. As a result, in the wireless communication device 400, the control unit 50A can determine whether or not the amplifier 10 has an abnormal load based on the power of the reflected signal. Further, in the wireless communication device 400, the power supply voltage supplied to the power control voltage generation unit 70 can be controlled differently depending on whether the amplifier 10 has an abnormal load or not.

The present invention is not limited to the above embodiment, and can be appropriately modified without departing from the spirit.

10 Amplifier 30 Current detector 40 Temperature detector 50, 50A Control unit 60 Variable regulator 70 Power control Voltage generator 100, 400 Wireless communication device

Claims (2)

An amplifier that amplifies the input signal based on the power control voltage,
A current detector that detects the current flowing through the amplifier,
A power control voltage generator that compares the voltage corresponding to the current with a reference voltage and generates the power control voltage for controlling the current flowing through the amplifier to be kept constant based on the comparison result.
A temperature detector that detects the temperature of the amplifier and
A variable regulator that can change the power supply voltage supplied to the power control voltage generator,
A control unit that controls the power supply voltage supplied from the variable regulator to the power control voltage generation unit based on the temperature.
Equipped with a,
The control unit
Comparing the temperature with a predetermined threshold,
When the temperature is equal to or lower than the predetermined threshold value, the power supply voltage is controlled to the first voltage.
When the temperature is higher than the predetermined threshold value, the power supply voltage is controlled to a second voltage which is a voltage lower than the first voltage.
Wireless communication device. Further equipped with a directional coupler and a detection circuit,
The directional coupler outputs a reflected signal output from the amplifier and reflected from the antenna to the detection circuit.
The detection circuit detects the power of the reflected signal and
The control unit further controls the power supply voltage of the variable regulator based on the power of the reflected signal.
The wireless communication device according to claim 1.

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