JP2011130257A - High frequency amplifier device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high frequency amplifier device that has a compact circuit size and high efficiency irrespective of a low output power, while being comparible with burst operation and consecutive operation of the high frequency amplifier. <P>SOLUTION: The device includes an amplifier 1, a variable voltage source 2 to be used as a voltage bias of the amplifier 1, and a control switch 6 placed between the amplifier 1 and the variable voltage source 2. The control switch 6 operates based on a burst control signal. The variable voltage source 2 controls an output voltage according to an average output power so as to raise the output voltage when the average output power is large, and lower the output voltage when the average output power is small. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-efficiency and small high-frequency amplifier.

  As a conventional high-frequency amplifier, a variable voltage source is used as a power supply bias such as a drain or collector of a single amplifier, an RF signal input to the input terminal is amplified by a single amplifier, electric power is taken out from the output terminal, and the average of the high-frequency amplifier There is one that realizes high-efficiency operation by controlling the output voltage of the variable voltage source according to the output power and operating the single amplifier near saturation regardless of the average output power (for example, see Non-Patent Document 1). .

Biranchinath Sahu et al. “A High Efficiency WCDMA RF Power Amplifier With Adaptive, Dual-Mode Buck-Boost Supply and Bias-Current Control”, Microwave and Wireless Components Letters, Volume 17, Issue 3, March 2007, pp. 238-240

  However, the prior art has the following problems. When making the high frequency amplifier perform a burst operation, a power supply bias such as a gate or a base is turned on / off based on the burst control signal to operate the single amplifier in a burst operation, and a variable voltage source is turned on / off based on the burst control signal. Thus, a method of causing the high frequency amplifier to perform a burst operation can be considered. However, when the power supply bias such as the gate or base is turned off while the variable voltage source is on, the isolation of the single amplifier is insufficient, and the RF signal input to the input terminal of the high frequency amplifier leaks to the output terminal. Outburst operation may not be performed. In addition, since the switching speed of the variable voltage source is on / off is slower than that of the burst control signal, the high frequency amplifier cannot be operated in burst by switching the variable voltage source on / off. For this reason, the conventional high-frequency amplifier is capable of continuous operation, but there is a problem that burst operation cannot be performed.

  The present invention has been made in order to solve the above-described problems, and provides a high-frequency amplifier having high efficiency and a small circuit size even when output power is low, while supporting burst operation and continuous operation of the high-frequency amplifier. For the purpose.

  The high-frequency amplifier according to the present invention includes an amplifier, a variable voltage source used as a power supply bias of the amplifier, and a control switch mounted between the high-frequency amplifier and the variable voltage source.

  According to the high frequency amplifier of the present invention, it is possible to obtain a high frequency amplifier having high efficiency and a small circuit size even when the output power is low, while supporting burst operation and continuous operation of the high frequency amplifier.

1 is a circuit diagram showing a high frequency amplifier according to a first embodiment of the present invention. It is a figure explaining the effect of the high frequency amplifier which concerns on Embodiment 1 of this invention. It is a figure explaining the effect of the high frequency amplifier which concerns on Embodiment 1 of this invention. It is a figure explaining the effect of the high frequency amplifier which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the high frequency amplifier which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the high frequency amplifier which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the high frequency amplifier which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention. It is a circuit diagram which shows the other example of the high frequency amplifier which concerns on Embodiment 5 of this invention.

  Hereinafter, preferred embodiments of a high-frequency amplifier according to the present invention will be described with reference to the drawings.

Embodiment 1 FIG.
1 is a circuit diagram showing a high-frequency amplifier according to Embodiment 1 of the present invention. The high-frequency amplifier shown in FIG. 1 includes a single amplifier 1, a variable voltage source 2 used as a power supply bias for the drain or collector of the single amplifier 1, and a control switch 6 loaded between the single amplifier 1 and the variable voltage source 2. And. In FIG. 1, 3 is a control terminal of a variable voltage source, 4 is an input terminal, and 5 is an output terminal.

  Next, the operation of the high frequency amplifier shown in FIG. 1 will be described. The RF signal input to the input terminal 4 is amplified by the single amplifier 1 and output power is taken out from the output terminal 5. At this time, the power supply circuit of the single amplifier 1 is composed of the variable voltage source 2 and the control switch 6. Since the operation of the high-frequency amplifier shown in FIG. 1 differs depending on the combination of these operations, a detailed description will be given below.

  A control signal is input to the control terminal 3 of the variable voltage source so that the output voltage of the variable voltage source 2 becomes a constant value, and the control switch 6 is switched on and off based on the burst control signal. The voltages at Va, Vb, and Vc in FIG. 1 at this time are shown in FIG. In FIG. 2, Va indicates that the output voltage of the variable voltage source 2 is constant. Vb indicates that a burst control signal is input. Since the control switch 6 is switched on and off based on the burst control signal, Vc when the control switch 6 is on is the voltage Va of the variable voltage source 2. When the control switch 6 is off, the power supply bias of the single amplifier 1 is 0V. Thus, Vc for the single amplifier 1 is a voltage at which the output voltage Va and 0 V of the variable voltage source 2 are alternately switched, so that the high frequency amplifier shown in FIG. 1 can perform a burst operation.

  Next, the case where the output voltage of the variable voltage source 2 is controlled by the control terminal 3 according to the average output power, and the control switch 6 is always on is shown. The voltage at each point Va, Vb, and Vc in FIG. 1 at this time is shown in FIG. Va in FIG. 3 indicates that the output voltage of the variable voltage source 2 changes according to the average output power. Vb indicates that the control switch 6 is always on. Vc becomes the output voltage Va of the variable voltage source 2 corresponding to the output power of the single amplifier 1 and is applied as a power supply bias of the single amplifier 1. As described above, the high-frequency amplifier shown in FIG. 1 is capable of high-efficiency operation because the power supply voltage is controlled according to the average output power and the single amplifier 1 operates near saturation regardless of the average output power.

  Next, consider a case where the output voltage of the variable voltage source 2 is controlled by the control terminal 3 in accordance with the average output power, and the control switch 6 switches on and off based on the burst control signal. FIG. 4 shows voltages at points Va, Vb, and Vc in FIG. 1 at this time. Va in FIG. 4 indicates that the output voltage of the variable voltage source 2 changes according to the average output power. Vb indicates that a burst control signal is input. Since the control switch 6 is switched on and off based on the burst control signal, Vc when the control switch 6 is turned on becomes the output voltage Va of the variable voltage source 2 corresponding to the output power of the single amplifier 1, and the control switch 6 It is shown that the power supply bias of the single amplifier 1 is 0V in the state where is turned off. As described above, the high-frequency amplifier shown in FIG. 1 is capable of high-efficiency operation because the power supply voltage is controlled according to the average output power and the single amplifier 1 operates near saturation regardless of the average output power. Since it is possible to control switching Vc on and off at the same time, burst operation is possible.

  Therefore, with the configuration shown in FIG. 1, the power supply voltage control is performed according to the average output power as in the conventional circuit, and a mode in which the high-frequency amplifier operates with high efficiency can be realized. The power supply voltage control is performed according to the mode and the average output power, and the high frequency amplifier operates with high efficiency, and further, three modes of burst operation can be realized. Further, since the saturated output power of the amplifier 1 can be varied by the variable voltage source 2, the high-frequency amplifier shown in FIG. 1 is always highly efficient even when the desired output power in each mode is different. Moreover, since these functions can be realized by adding the control switch 6 to the conventional circuit, a small circuit size can be realized.

  The high-frequency amplifier that can be realized by the amplifier shown in FIG. 1 performs the power supply voltage control according to the burst operation mode and the average output power and performs the high-efficiency operation mode and the average output power of the high-frequency amplifier. As an example of three operation modes of a mode in which a high-efficiency operation and a burst operation are performed, there are a GSM system, a W-CDMA system, and a PDC system for mobile phones, respectively. These three communication systems differ in the maximum output power required for the amplifier and the mode of operation. The amplifier shown in FIG. 1 can cope with the maximum output power in any mode by changing the power supply bias voltage, and can realize high efficiency at the maximum output in any mode. .

Embodiment 2. FIG.
5 is a circuit diagram showing a high frequency amplifier according to Embodiment 2 of the present invention. The high frequency amplifier shown in FIG. 5 is connected in parallel to the single amplifier 1, the variable voltage source 2 used as the power source bias of the drain or collector of the single amplifier 1, and the output terminal and the power terminal of the variable voltage source 2. And a control switch 6. In FIG. 5, 3 is a control terminal of the variable voltage source 2, 4 is an input terminal, 5 is an output terminal, and 7 is a power source.

  Next, the operation of the high frequency amplifier shown in FIG. 5 will be described. The RF signal input to the input terminal 4 is amplified by the single amplifier 1 and output power is taken out from the output terminal 5. The control switch 6 and the variable voltage source 2 will be described below because the operation of the high-frequency amplifier shown in FIG. 5 differs for each combination of operations.

  A case will be described in which a control signal is input to the control terminal 3 of the variable voltage source 2 to turn off the variable voltage source 2, and the control switch 6 switches on and off based on the burst control signal. Based on the burst control signal, when the control switch 6 is on, the voltage of the power supply 7 becomes the power supply bias of the single amplifier 1. When the control switch 6 is off, the power supply bias of the single amplifier 1 is 0V. Thus, since the power supply bias of the single amplifier 1 is a voltage at which the output voltage of the variable voltage source 2 and 0 V are alternately switched, the high frequency amplifier shown in FIG. 5 can perform a burst operation.

  Next, the case where the output voltage of the variable voltage source 2 is controlled by the control terminal 3 according to the average output power and the control switch 6 is always off will be described. At this time, the output voltage of the variable voltage source 2 corresponding to the average output power of the single amplifier 1 becomes the power supply bias of the single amplifier 1. Therefore, the high-frequency amplifier shown in FIG. 5 is capable of high-efficiency operation because the power supply voltage is controlled according to the average output power and the single amplifier 1 operates near saturation regardless of the average output power.

  Therefore, the circuit shown in FIG. 5 can realize a mode in which burst operation is performed in addition to realizing a mode in which the high-frequency amplifier operates with high efficiency by performing power supply voltage control according to the average output power as in the conventional circuit. Become. Further, since the saturation output power of the amplifier can be varied by the variable voltage source 2, the high-frequency amplifier shown in FIG. 5 is always highly efficient even when the desired output power in each mode is different. Moreover, since these functions can be realized by adding the control switch 6 to the conventional circuit, a small circuit size can be realized. Furthermore, since there is no control switch 6 in the power supply path in a mode in which the power supply voltage is controlled according to the average output power and the high frequency amplifier operates with high efficiency as compared with the first embodiment, there is no voltage drop in the control switch 6, The high frequency amplifier becomes highly efficient.

  Examples of two operation modes that can be realized by the amplifier shown in FIG. 5 are a burst operation mode and a mode in which the power supply voltage is controlled according to the average output power and the high-frequency amplifier operates with high efficiency. System and W-CDMA system. These two communication systems differ in the maximum output power required for the amplifier and the mode of operation. The amplifier shown in FIG. 5 can cope with the maximum output power of any mode by changing the power supply bias voltage, and can realize high efficiency at the maximum output of any mode. .

Embodiment 3 FIG.
FIG. 6 is a circuit diagram showing a high frequency amplifier according to Embodiment 3 of the present invention. The high-frequency amplifier shown in FIG. 6 includes a single amplifier 1, a variable voltage source 2, a control switch 6, and an amplifier 8 in a driver stage. In FIG. 6, 3 is a control terminal of the variable voltage source 2, 4 is an input terminal, and 5 is an output terminal. The high frequency amplifier shown in FIG. 6 shows an example in which the first embodiment is applied to both the driver stage amplifier 8 and the final stage amplifier 1 in a multistage amplifier. As shown in FIG. 6, by applying Embodiment 1 or Embodiment 2 to a multistage amplifier, it is possible to increase the efficiency of the high-frequency amplifier compared to the conventional circuit. In addition, a high gain can be achieved by increasing the number of stages of the high-frequency amplifier. Furthermore, by sharing the variable voltage source 2 and the control switch 6 for these amplifiers, the circuit size can be reduced. Since the final stage amplifier 1 and the driver stage amplifier 8 before the final stage have a large output power and have a dominant influence on the efficiency of the multistage amplifier, the first embodiment or When the second embodiment is applied, the circuit size can be further reduced.

  The configuration shown in FIG. 6 shows the case where the first embodiment is multistage, but as shown in FIG. 7, both the driver stage amplifier 8 and the final stage amplifier 1 in the multistage amplifier constituting the high frequency amplifier shown in FIG. The same effect can be obtained when the first embodiment applied to is changed to the second embodiment.

Embodiment 4 FIG.
FIG. 8 is a circuit diagram showing a high frequency amplifier according to Embodiment 4 of the present invention. The high-frequency amplifier shown in FIG. 8 includes a single amplifier 1, a control switch 6, and a DC / DC converter 9 used as a variable voltage source. In FIG. 8, 3 is a control terminal, 4 is an input terminal, and 5 is an output terminal. The high frequency amplifier shown in FIG. 8 shows an example in which the DC / DC converter 9 capable of changing the voltage with high efficiency is used as the variable voltage source 2 in the high frequency amplifier in the amplifier of the first embodiment. In the high-frequency amplifier shown in FIG. 8, the same effect as that of the high-frequency amplifier according to the first embodiment can be obtained by using the DC / DC converter 9 capable of changing the voltage with high efficiency as the variable voltage source. Furthermore, by using a DC / DC converter 9 having a small circuit size and arranging it in the immediate vicinity of the amplifier 1, the voltage drop due to the wiring is reduced, so that the high frequency amplifier becomes highly efficient.

  In the configuration shown in FIG. 8, the case where the DC / DC converter 9 capable of changing the voltage with high efficiency is used as the variable voltage source 2 of the first embodiment is shown. However, as shown in FIG. The same effect is obtained when the DC / DC converter 9 capable of changing the voltage with high efficiency is used as the variable voltage source 2 of the second embodiment.

  Further, in the configuration shown in FIG. 8, the case where the DC / DC converter 9 that can change the voltage with high efficiency is used as the variable voltage source 2 of the first embodiment is shown. As described above, the same effect can be obtained when the DC / DC converter 9 capable of changing the voltage with high efficiency is used as the variable voltage source 2 of the third embodiment.

Embodiment 5 FIG.
FIG. 12 is a circuit diagram showing a high frequency amplifier according to Embodiment 5 of the present invention. The high-frequency amplifier shown in FIG. 12 includes a single amplifier 1, a variable voltage source 2, and a p-channel MOSFET 10 loaded between the single amplifier 1 and the variable voltage source 2. In FIG. 12, 3 is a control terminal of the variable voltage source 2, 4 is an input terminal, and 5 is an output terminal. The high frequency amplifier shown in FIG. 12 shows an example in which a p-channel MOSFET 10 is used as the control switch 6 in the high frequency amplifier in the amplifier of the first embodiment. A burst control signal is input to the gate terminal of the p-channel MOSFET 10, the variable voltage source 2 is connected to the source terminal, and the drain terminal is connected to the output side bias circuit of the amplifier 1. Since the p-channel MOSFET 10 can control the current between the source and the drain with the potential between the gate and the source, the function of the control switch 6 can be realized with an extremely small voltage drop, and the high-frequency amplifier becomes highly efficient. Further, since the control switch 6 can be realized only by the p-channel MOSFET 10, the circuit can be made smaller than the high-frequency amplifier of the first embodiment. Although a p-channel MOSFET is shown in FIG. 12, a similar effect can be obtained if the device can control the on / off of the current by the potential difference between the control terminal and the power supply terminal, such as a pnp transistor.

  In the configuration shown in FIG. 12, the case where the p-channel MOSFET 10 is used as the control switch 6 of the first embodiment is shown. However, as shown in FIG. 13, the case where the p-channel MOSFET 10 is used as the control switch 6 of the second embodiment. Has the same effect.

  12 shows the case where the p-channel MOSFET 10 is used as the control switch 6 of the first embodiment. However, as shown in FIGS. 14 and 15, the p-channel MOSFET 10 is used as the control switch 6 of the third embodiment. The same effect is obtained when the MOSFET 10 is used.

  Furthermore, in the configuration shown in FIG. 12, the case where the p-channel MOSFET 10 is used as the control switch 6 of the first embodiment is shown. However, as shown in FIGS. 16, 17, 18, and 19, the control of the fourth embodiment is performed. The same effect is obtained when the p-channel MOSFET 10 is used as the switch 6.

  1 single amplifier, 2 variable voltage source, 3 control terminal, 4 input terminal, 5 output terminal, 6 control switch, 7 power supply, 8 driver stage amplifier, 9 DC / DC converter, 10 p-channel MOSFET.

Claims (9)

An amplifier;
A variable voltage source used as a power supply bias of the amplifier;
A high-frequency amplifier comprising a control switch loaded between the amplifier and the variable voltage source. The high frequency amplifier according to claim 1, wherein
The high-frequency amplifier, wherein the control switch operates based on a burst control signal. The high-frequency amplifier according to claim 1 or 2,
The variable voltage source controls the output voltage according to the average output power so that the output voltage is increased when the average output power is large and the output voltage is decreased when the average output power is small. . An amplifier;
A variable voltage source used as a power supply bias of the amplifier;
A high-frequency amplifier comprising an output terminal of the variable voltage source and a control switch connected in parallel to the power supply terminal. The high frequency amplifier according to claim 4,
The variable voltage source is turned off during burst operation,
The high-frequency amplifier, wherein the control switch operates based on a burst control signal. The high-frequency amplifier according to claim 4 or 5,
The control switch is turned off during continuous operation,
The variable voltage source controls the output voltage according to the average output power so that the output voltage is increased when the average output power is large and the output voltage is decreased when the average output power is small. . The high frequency amplifier according to any one of claims 1 to 6,
The amplifier has a multi-stage configuration,
The high-frequency amplifier, wherein the variable voltage source and the control switch are shared. The high-frequency amplifier according to any one of claims 1 to 7,
A high-frequency amplifier using a DC / DC converter as the variable voltage source. The high frequency amplifier according to any one of claims 1 to 8,
A high-frequency amplifier using a p-channel MOSFET or a pnp transistor as the control switch.

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