JP2004207939A - Power amplifier - Google Patents

Power amplifier Download PDF

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Publication number
JP2004207939A
JP2004207939A JP2002373615A JP2002373615A JP2004207939A JP 2004207939 A JP2004207939 A JP 2004207939A JP 2002373615 A JP2002373615 A JP 2002373615A JP 2002373615 A JP2002373615 A JP 2002373615A JP 2004207939 A JP2004207939 A JP 2004207939A
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JP
Japan
Prior art keywords
power amplifier
power
output
impedance
power supply
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP2002373615A
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Japanese (ja)
Inventor
Hiroki Sato
Fumito Tomaru
広樹 佐藤
史人 都丸
Original Assignee
Hitachi Kokusai Electric Inc
株式会社日立国際電気
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Kokusai Electric Inc, 株式会社日立国際電気 filed Critical Hitachi Kokusai Electric Inc
Priority to JP2002373615A priority Critical patent/JP2004207939A/en
Publication of JP2004207939A publication Critical patent/JP2004207939A/en
Pending legal-status Critical Current

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Abstract

A power amplifier in a transmitter that requires various antenna outputs realizes a common configuration of the same device and the same matching circuit and has a high efficiency power amplifier even when the transmitter outputs are different. The task is to provide.
The power supply voltage of a power amplifier is changed, the power amplifier is optimized according to the transmission output power of various transmitters, and the impedance change accompanying the power amplifier is automatically corrected by impedance adjustment means. , A common power amplifier and high efficiency.
[Selection diagram] Fig. 1

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
[0002]
[Prior art]
In a transmitter used for wireless communication, the required antenna output power varies depending on the specifications of the communication system, radio wave propagation conditions, communication distance, and the like. For example, in the case of a municipal disaster prevention wireless system, there are a base station and an outdoor slave station, respectively, and the required transmission power differs depending on the distance between the base stations and the number of outdoor slave stations, the installation location, and the like. Accordingly, the output power required for the power amplifier in the transmitter also differs. Here, three types of power amplifiers for transmitter outputs of 1 W, 3 W, and 5 W are considered.
[0003]
10 shows a configuration of a 1 W power amplifier, FIG. 12 shows a configuration of a 3 W power amplifier, and FIG. 13 shows a configuration of a 5 W power amplifier. The operation of FIG. 10 will be described. The transmission signal input from the input terminal 1 is input to the transistor 19 via the input matching circuit 18. The transmission signal amplified by the transistor 19 is matched through an output matching circuit 20 and output. The power supply 3 is supplied to the choke coil 4 and the power supply 7 is supplied to the base and collector of the transistor 19 via the choke coil 8 to operate the transistor 19.
[0004]
The average power P ave of the 1-W power amplifier considered as an example in which the modulation method is 16 QAM (α = 0.2) is P ave = antenna, where the power loss from the power amplifier output to the antenna is 2 dB. Output (+30 dBm) + power loss (2 dB) = + 32 dBm. Further, assuming that the required maximum power Pmax is a peak factor of 62 dB and a margin is 2 dB, Pmax ≧ power amplifier average output (+32 dBm) + peak factor (6 dB) + margin (2 dB) = + 40 dBm (10 W).
[0005]
Thus, as shown in FIG. 11, the power amplifier needs to be operated at a point where the back-off is at least 8 dB from the maximum power. In general, the efficiency of a power amplifier increases as the back-off decreases. Considering these two, it is considered optimal to operate at the point of 8 dB back-off. As described above, a device having a maximum output of 10 W is selected as a device used for the 1 W power amplifier, and a matching circuit suitable for the device is manufactured to realize the 1 W power amplifier.
[0006]
Next, a 3W power amplifier will be described with reference to FIG. The configuration is the same as in FIG. In this case, since the antenna output is 3 W (+34.8 dBm), the power amplifier average output is 34.8 dBm + 2 dB = 36.8 dBm, and the maximum output is 36.8 dBm + 8 dB = 44.8 dBm (30 W), considering the loss to the antenna. Become. Therefore, a device having a maximum output of 30 W is selected as a device used for the 3 W power amplifier, and a matching circuit suitable for the device is manufactured to realize the 3 W power amplifier.
[0007]
The 5W power amplifier will be described with reference to FIG. The configuration is the same as in FIG. In this case, since the antenna output is 5 W (+37 dBm), the power amplifier average output is 37 dBm + 2 dB = 39 dBm, and the maximum output is 39 dBm + 8 dB = 47 dBm (50 W), considering the loss to the antenna. Therefore, a device having a maximum output of 50 W is selected as a device used for the 5 W power amplifier, and a matching circuit suitable for the device is manufactured to realize the 5 W power amplifier.
[0008]
As described above, a power amplifier having various outputs according to the transmitter output is realized. As another example, there is a conventional example in which a power amplifier for 5 W is manufactured and an input or output is limited by an attenuator to realize a power amplifier for 3 W and 1 W.
[0009]
[Problems to be solved by the invention]
In the above-described conventional example, when an optimum power amplifier is required in accordance with various transmitter outputs, the optimum devices must be individually selected and manufactured. Therefore, there has been a problem that the number of components and the number of adjustment steps increase. Further, when input or output is restricted to realize power amplifiers of various outputs, there is a problem that efficiency is deteriorated.
[0010]
An object of the present invention is to provide a high-efficiency power amplifier while realizing a common configuration of the same device and the same matching circuit even when the transmitter outputs are different.
[0011]
[Means for Solving the Problems]
The present invention achieves the above object by changing the power supply voltage of a power amplifier, optimizing the power amplifier with various transmitter outputs, and adjusting the resulting impedance change by an impedance adjuster. The amplifier is used in common and the efficiency is increased.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows the configuration of an embodiment of the present invention, and this will be described first. In FIG. 1, an input terminal 1 is connected to a transistor 5 via an input matching circuit 2. The transistor 5 is connected to an output matching circuit 11, and the output matching circuit 11 is connected to an output terminal 13 via an impedance adjuster 12. The power supply 3 is connected to the transistor 5 via the choke coil 4, and the power supply 7 is connected to the transistor 5 via the DC / DC converter 6 and the choke coil 8. The DC / DC converter is connected to the impedance adjuster 12 via the voltage detector 9 and the control unit 10.
[0013]
Hereinafter, the operation of this embodiment will be described. The transmission signal input from the input terminal 1 is input to the input matching circuit 2 and matched with the input of the transistor 5. The signal input to the transistor 5 is amplified to a desired power. The impedance of the signal matched by the output matching circuit 11 is finely adjusted by the impedance adjuster 12 and output from the output terminal 13. The power supply 3 is supplied to the transistor 5 by the choke coil 4, and the power supply 7 is supplied to the transistor 5 by the choke coil 8 via the DC / DC converter 6. As described above, when the maximum output of the power amplifier required by various transmitter outputs is different, the power supply 7 is realized by changing the supply voltage to the transistor 5 by the DC / DC converter 6 because it is a fixed power supply. Here, since the impedance changes with the change in the supply voltage to the transistor 5, the voltage is detected by the voltage detector 9, and the impedance is corrected by the control unit 10 using the impedance adjuster 12.
[0014]
This operation will be described in detail below. A case where a power amplifier for a modulation method of 16 QAM (α = 0.2) and an antenna output of 5 W, 3 W, and 1 W is required will be described with reference to FIG. FIG. 2 shows the input / output characteristics of the power amplifier. As described above, the average power of the power amplifier for 5 W is +39 dBm (8 W), and the required maximum output is 47 dBm (50 W) in consideration of the peak factor and the margin. That is, as shown in FIG. 2, the operation is performed at the point of the back-off of 8 dB. Here, it is assumed that there is a device A whose maximum power is +47 dBm (50 W) at a power supply voltage of 28 V. First, the supply voltage to the transistor is set to 28 V by a DC / DC converter, and the output matching circuit is optimally adjusted as a 5 W power amplifier.
[0015]
Next, when a 3W power amplifier is required, the average output is +36.8 dBm and the required maximum output is +44.8 dBm (30 W) as described above. Here, assuming that power P, voltage V, and load resistance R, P = V 2 / R. From the relationship of P∝V 2 (1), in order to set the maximum output power to 30 W, the voltage is applied to the device A. The required voltage can be obtained as 21.6 V from the above equation (1). The power supply voltage is set from 28 V to 21.6 V by a DC / DC converter.
[0016]
Changing the power supply voltage also changes the impedance of the device. A method of correcting the change will be described with reference to FIGS. First, the movement on the Smith chart when each element is connected will be briefly described with reference to FIGS. As shown in FIG. 4, when the inductor is connected in series (L 1 ), it moves clockwise on the constant resistance circle, and when the capacitor is connected in parallel (C 1 ), it moves clockwise on the constant conductance circle. When the capacitors are connected in series (C 2 ), they move counterclockwise on the constant resistance circle, and when the inductors are connected in parallel (L 2 ), they move counter clockwise on the constant conductance circle. For example, when the connection is made as shown in FIG. 3, starting from the input impedance Z in = 15Q, the locus as L 1 , C 1 , C 2 , L 2 is drawn as shown in FIG. 3, and the output impedance Z out = R + jX. Become mobile.
[0017]
Based on this, a method of correcting the impedance of the device when the power supply voltage is changed and the impedance of the device is changed will be described with reference to FIGS. As an example, it is assumed that a transmission frequency of 60 MHz and an output matching circuit are matched by three elements of a series L (40 nH), a parallel C (130 pF), and a series C (0.1 μF) as shown in FIG. The power supply variation, the output impedance of the device Z dev'when changes to the output impedance Z out → Z out with it' Z dev changes. The change in Z out is corrected by the impedance adjuster.
[0018]
A method for automatically controlling this using a voltage detector and a control unit will be described below. First, the output impedance Z dev of the device at each power supply voltage is measured. The output impedance Z out of the matching circuit at the output impedance Z dev of each power supply voltage is obtained. When the output impedance Z out of the matching circuit is obtained, the amount of impedance correction by the impedance adjuster is also obtained. The correction for the impedance converter at each power supply voltage is created as a table, and the control unit automatically adjusts the impedance adjuster based on the table created by detecting the power supply voltage. The following can optimize the power amplifier for 3W.
[0019]
When the power amplifier for 1W is similarly considered, the power supply voltage is set to 12.5V according to the above equation (1), and the output impedance is corrected by an impedance adjuster to optimize the power amplifier for 1W. be able to. As described above, by setting the power supply voltage, it is possible to realize an optimal power amplifier according to various transmitter outputs.
[0020]
Next, another embodiment of the present invention will be described with reference to FIGS. The configuration of another embodiment is shown in FIG. 7 and will be described first. In FIG. 7, an input terminal 1 is connected to a transistor 5 via an input matching circuit 2. The transistor 5 is connected to the output matching circuit 11, and the output matching circuit 11 is connected to the output terminal 13 via the phase adjuster 14 and the variable capacitor 15. The power supply 3 is connected to the transistor 5 via the choke coil 4, and the power supply 7 is connected to the transistor 5 via the DC / DC converter 6 and the choke coil 8. The DC / DC converter is connected to the phase adjuster 14 and the variable capacitor 15 via the voltage detector 9 and the control unit 10.
[0021]
Hereinafter, the operation of this embodiment will be described. The transmission signal input from the input terminal 1 is input to the input matching circuit 2 and matched with the input of the transistor 5. The signal input to the transistor 5 is amplified to a desired power. The signal matched by the output matching circuit 11 has its impedance finely adjusted by the phase adjuster 14 and the variable capacitor 15 and is output from the output terminal 13. Similarly, in order to optimize the power amplifier with various antenna outputs, a change in impedance caused when the power supply voltage is changed is adjusted by a phase adjuster and a variable capacitor as shown in FIG. Similarly, the power supply voltage is detected, and the phase adjuster and the variable capacitor are automatically adjusted. As described above, by setting the power supply voltage required for each antenna output, a power amplifier optimal for each output can be realized.
[0022]
【The invention's effect】
According to the present invention, by optimizing the power supply voltage of the power amplifier so as to correspond to various antenna outputs, and automatically correcting an impedance change accompanying the power supply voltage by the impedance adjuster, it is possible to use a common transmitter for various antenna outputs. , High efficiency can be achieved.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing a configuration of one embodiment of the present invention.
FIG. 2 is a graph illustrating the operation of one embodiment of the present invention.
FIG. 3 is a diagram illustrating the operation of one embodiment of the present invention.
FIG. 4 is a Smith chart illustrating the operation of one embodiment of the present invention.
FIG. 5 is a diagram for explaining the operation of one embodiment of the present invention.
FIG. 6 is a Smith chart illustrating the operation of one embodiment of the present invention.
FIG. 7 is a circuit diagram showing a configuration of another embodiment of the present invention.
FIG. 8 is a diagram for explaining the operation of another embodiment of the present invention.
FIG. 9 is a Smith chart illustrating the operation of another embodiment of the present invention.
FIG. 10 is a circuit diagram showing an example of a conventional technique.
FIG. 11 is a graph illustrating an operation example of the related art.
FIG. 12 is a circuit diagram showing an example of a conventional technique.
FIG. 13 is a circuit diagram showing an example of a conventional technique.
[Explanation of symbols]
1: input terminal, 2, 18, 21, 24: input matching circuit, 3, 7: power supply, 4, 8: choke coil, 5, 19, 22, 25: transistor, 6: DC / DC converter, 9: voltage Detector, 10: control unit, 11, 20, 23, 26: output matching circuit, 12: impedance adjuster, 13: output terminal, 14: phase adjuster, 15: variable capacitor.

Claims (4)

  1. What is claimed is: 1. A power amplifier used for wireless communication, comprising: means for optimizing a power supply voltage of a power amplifier according to a transmission output power required by a propagation condition and a communication distance.
  2. The power amplifier according to claim 1,
    A power amplifier, comprising: an impedance adjuster that corrects a change in impedance due to a change in the power supply voltage.
  3. The power amplifier according to claim 2,
    A power amplifier having a phase adjuster and a variable capacitor in the impedance adjuster.
  4. The power amplifier according to claim 2,
    A power amplifier comprising means for detecting the power supply voltage and automatically adjusting an impedance adjuster.
JP2002373615A 2002-12-25 2002-12-25 Power amplifier Pending JP2004207939A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2002373615A JP2004207939A (en) 2002-12-25 2002-12-25 Power amplifier

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2002373615A JP2004207939A (en) 2002-12-25 2002-12-25 Power amplifier

Publications (1)

Publication Number Publication Date
JP2004207939A true JP2004207939A (en) 2004-07-22

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Family Applications (1)

Application Number Title Priority Date Filing Date
JP2002373615A Pending JP2004207939A (en) 2002-12-25 2002-12-25 Power amplifier

Country Status (1)

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JP (1) JP2004207939A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006093896A (en) * 2004-09-21 2006-04-06 Matsushita Electric Ind Co Ltd Class-e amplifier and eer modulation amplifier device
US7602243B2 (en) 2006-11-15 2009-10-13 Yoji Murao Amplifier
JP2012010082A (en) * 2010-06-24 2012-01-12 Netcomsec Co Ltd Transmission power amplifier

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2006093896A (en) * 2004-09-21 2006-04-06 Matsushita Electric Ind Co Ltd Class-e amplifier and eer modulation amplifier device
JP4536468B2 (en) * 2004-09-21 2010-09-01 パナソニック株式会社 Class E amplifier and EER modulation amplifier
US7602243B2 (en) 2006-11-15 2009-10-13 Yoji Murao Amplifier
JP2012010082A (en) * 2010-06-24 2012-01-12 Netcomsec Co Ltd Transmission power amplifier

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