Power amplifier output power control circuit, radio frequency power amplifier circuit and communication equipment

Abstract

The utility model discloses a power amplifier output power control circuit, a radio frequency power amplifier circuit and communication equipment. The power amplifier output power control circuit comprises a multiplication circuit and a comparison circuit, the multiplication circuit is connected with a power supply and an input end of a power amplifier and used for generating feedback voltage based on voltage and current of the input end of the power amplifier, and the comparison circuit is connected with the multiplication circuit and used for generating control voltage based on the feedback voltage and reference voltage to control the power amplifier. Therefore, the output power of the power amplifier is kept stable. Through the mode, the power amplifier output power control circuit can utilize the characteristic that the power amplifier efficiency is almost unchanged under the condition that the voltage and the current of the power amplifier are not greatly changed, the power consumption of the power amplifier is equivalent to the power amplifier output power, and then the power amplifier output power is utilized to control the power amplifier, so that the output power of the power amplifier is kept stable; and the product performance is greatly improved.

Description

Technical Field

[0001] The present application relates to the technical field of communication power control, and in particular to a power amplifier output power control circuit, a radio frequency power amplifier circuit and a communication device. Background Art

[0002] Existing digital media receiver products have a variety of frequency bands, including VHF band (136-174M), U1 band (400-470M), U2 band (450-520M), U3 band (350-400M), U5 band, etc. The output power of each band has various power requirements of 0.5W to 50W, and its power control requirements are high. Power amplifier output power control is one of the key and difficult indicators in the power amplifier development process. At present, the main problems of power control are as follows: first, the high and low voltage power fluctuations are large; second, the current fluctuations are large in different load environments; third, the high voltage heat dissipation power consumption is large. Utility Model Content

[0003] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a power amplifier output power control circuit, which includes a multiplication circuit and a comparison circuit. The multiplication circuit is connected to a power supply and an input end of the power amplifier, and is used to generate a feedback voltage based on the voltage and current at the input end of the power amplifier. The comparison circuit is connected to the multiplication circuit, and is used to generate a control voltage based on the feedback voltage and a reference voltage to control the power amplifier so as to maintain the output power of the power amplifier stable.

[0004] Among them, the multiplication circuit includes a multiplier, a power amplifier current input circuit and a power amplifier voltage input circuit. The power amplifier current input circuit is connected to a power supply, an input end of the power amplifier and a first input end of the multiplier. The multiplier is used to obtain a first voltage across the power amplifier current input circuit; the power amplifier voltage input circuit is connected to the input end of the power amplifier and a second input end of the multiplier, and is used to output a second voltage to the multiplier based on the voltage at the input end of the power amplifier; wherein the multiplier is used to calculate the product of the first voltage and the second voltage to obtain a feedback voltage.

[0005] Among them, the power amplifier current input circuit includes a first resistor, the first end of the first resistor is connected to the power supply, the second end of the first resistor is connected to the input end of the power amplifier, and the first input end of the multiplier is respectively connected to the first end and the second end of the first resistor for obtaining a first voltage.

[0006] Among them, the power amplifier voltage input circuit includes a second resistor and a third resistor, the first end of the second resistor is connected to the input end of the power amplifier; the first end of the third resistor is connected to the second end of the second resistor, and the second end of the third resistor is grounded; the second input end of the multiplier is connected to the second end of the second resistor for obtaining the second voltage.

[0007] The resistance of the second resistor and the resistance of the third resistor are greater than the resistance of the first resistor.

[0008] Among them, the comparison circuit includes a comparator, a first input terminal of the comparator is connected to the output terminal of the multiplier and receives a feedback voltage, and a second input terminal of the comparator receives a reference voltage; wherein the comparator generates a control voltage based on the comparison between the reference voltage and the feedback voltage and outputs it to the control terminal of the power amplifier to control the power amplifier.

[0009] Among them, the comparison circuit also includes a first zener tube and a second zener tube, the first end of the first zener tube is grounded, and the second end of the first zener tube is connected to the first input end of the comparator; the first end of the second zener tube is grounded, and the second end of the second zener tube is connected to the output end of the comparator.

[0010] Among them, the comparison circuit also includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a capacitor; the fourth resistor is used to receive a reference voltage and is connected to the second input terminal of the comparator; the first end of the fifth resistor is connected to the output terminal of the multiplier, and the second end of the fifth resistor is connected to the first input terminal of the comparator; the sixth resistor and the capacitor are connected in parallel between the first input terminal of the comparator and the output terminal of the comparator, the first end of the seventh resistor is connected to the output terminal of the comparator, and the second end of the seventh resistor is used to output a control voltage.

[0011] In order to solve the above technical problems, a technical solution adopted in the present application is: to provide a radio frequency power amplifier circuit, which includes a power supply, a power amplifier and a power amplifier output power control circuit of any one of the above items, and a comparison circuit is connected to the power amplifier to output a control voltage to the control end of the power amplifier to maintain the output power of the power amplifier stable.

[0012] In order to solve the above technical problem, a technical solution adopted in the present application is: to provide a communication device, which includes the above-mentioned radio frequency power amplifier circuit.

[0013] The beneficial effect of the present application is that, different from the prior art, the power amplifier output power control circuit of the present application includes a multiplication circuit and a comparison circuit, the multiplication circuit is connected to the power supply and the input end of the power amplifier, and is used to generate a feedback voltage based on the voltage and current of the input end of the power amplifier, and the comparison circuit is connected to the multiplication circuit, and is used to generate a control voltage based on the feedback voltage and the reference voltage to control the power amplifier, so that the output power of the power amplifier is maintained stable. Through the above method, the power amplifier output power control circuit of the present application can utilize the characteristic that the power amplifier efficiency is almost unchanged when the voltage and current of the power amplifier do not change much, and equate the power amplifier power consumption to the power amplifier output power, and then use the power amplifier output power to control the power amplifier, so that the output power of the power amplifier is maintained stable, and the product performance is greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. Among them:

[0015] Figure 1 It is a structural schematic diagram of the first embodiment of the power amplifier output power control circuit of the present application;

[0016] Figure 2 1 is a schematic diagram of the structure of a multiplier embodiment;

[0017] Figure 3 It is a structural schematic diagram of a second embodiment of the power amplifier output power control circuit of the present application;

[0018] Figure 4 It is a structural schematic diagram of a third embodiment of the power amplifier output power control circuit of the present application;

[0019] Figure 5 It is a structural schematic diagram of an embodiment of a radio frequency power amplifier circuit of the present application;

[0020] Figure 6 It is a structural diagram of an embodiment of the communication device of the present application. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0022] Existing digital media receiver products have a variety of frequency bands, including VHF band (136-174M), U1 band (400-470M), U2 band (450-520M), U3 band (350-400M), U5 band, etc. The output power of each band has various power requirements of 0.5W to 50W, and its power control requirements are high. Power amplifier output power control is one of the key and difficult indicators in the power amplifier development process. At present, the main problems of power control are as follows: first, the high and low voltage power fluctuations are large; second, the current fluctuations are large in different load environments; third, the high voltage heat dissipation power consumption is large.

[0023] In the prior art, the first power control method is to detect current or voltage and perform negative feedback control on the amplifier gate voltage, but this method can only control current or voltage alone, and its power control is not accurate, and the power control debugging is difficult and has a long cycle, and even requires repeated debugging. The second power control method is to use power coupling combined with RF detection and then compare it with the reference voltage to control the RF link input or output, and then control the output power, but this method is more complex in design and occupies a large space on the circuit board.

[0024] In order to solve the above power control problem, the present application first proposes a power amplifier output power control circuit. Figure 1 , Figure 1 1 is a schematic diagram of the structure of the first embodiment of the power amplifier output power control circuit of the present application. Figure 1 As shown, the power amplifier output power control circuit 100 of this embodiment includes a multiplication circuit 20 and a comparison circuit 30 .

[0025] Among them, the multiplication circuit 20 is connected to the power supply 10 and the input end of the power amplifier, and is used to generate a feedback voltage based on the voltage and current at the input end of the power amplifier. The comparison circuit 30 is connected to the multiplication circuit 20, and is used to generate a control voltage based on the feedback voltage and the reference voltage to control the power amplifier so that the output power of the power amplifier remains stable.

[0026] In this embodiment, the multiplication circuit 20 of this embodiment is connected to the power supply 10 and the input end of the power amplifier, and is used to obtain the product of the voltage and current at the input end of the power amplifier to obtain the power consumption of the power amplifier. This embodiment utilizes the characteristic that the power amplifier efficiency is almost unchanged when the power amplifier voltage and current do not change much, and equates the total power consumption of the power amplifier to the output power of the power amplifier. The multiplication circuit 20 is used to generate a feedback voltage. Based on the feedback voltage and the comparison circuit 30, feedback control of the power amplifier can be achieved, thereby controlling the output power of the power amplifier to maintain stability.

[0027] Different from the prior art, the power amplifier output power control circuit 100 of the present application includes a multiplication circuit 20 and a comparison circuit 30. The multiplication circuit 20 is connected to the power supply 10 and the input end of the power amplifier, and is used to generate a feedback voltage based on the voltage and current of the input end of the power amplifier. The comparison circuit 30 is connected to the multiplication circuit 20, and is used to generate a control voltage based on the feedback voltage and the reference voltage to control the power amplifier, so that the output power of the power amplifier is maintained stable. In the above manner, the power amplifier output power control circuit 100 of the present application can utilize the characteristic that the power amplifier efficiency is almost unchanged when the power amplifier voltage and current do not change much, and equate the power amplifier power consumption to the power amplifier output power, and then use the power amplifier output power to control the power amplifier, so that the output power of the power amplifier is maintained stable, and the product performance is greatly improved.

[0028] Alternatively, if Figure 1As shown, in this embodiment, the multiplication circuit 20 includes a multiplier 23, a power amplifier current input circuit 21 and a power amplifier voltage input circuit 22. The power amplifier current input circuit 21 is connected to the power supply 10, the input end of the power amplifier and the first input end of the multiplier 23. The multiplier 23 is used to obtain a first voltage across the power amplifier current input circuit 21; the power amplifier voltage input circuit 22 is connected to the input end of the power amplifier and the second input end of the multiplier 23, and is used to output a second voltage to the multiplier 23 based on the voltage at the input end of the power amplifier; wherein the multiplier 23 is used to calculate the product of the first voltage and the second voltage to obtain a feedback voltage.

[0029] In this embodiment, the power amplifier current input circuit 21 is used to obtain the current of the input terminal of the power amplifier, and generate a first voltage corresponding to the current based on the current of the input terminal of the power amplifier. The power amplifier voltage input circuit 22 is used to obtain the voltage of the input terminal of the power amplifier, and generate a second voltage corresponding to the voltage based on the voltage of the input terminal of the power amplifier.

[0030] In this embodiment, the multiplier 23 calculates a feedback voltage based on the first voltage and the second voltage, wherein the feedback voltage is proportional to the product of the voltage and the current at the input end of the power amplifier.

[0031] In this embodiment, the multiplier 23 can be set to any one of an AD633 multiplier, an MPY100 multiplier, an MPY534 multiplier, an MPY634 multiplier or an LMK04906 multiplier.

[0032] Among them, taking AD633 multiplier as an example, please refer to Figure 2 , Figure 2 Schematic diagram of the structure of a multiplier embodiment. Figure 2 As shown, the multiplier is an AD633 multiplier, and the AD633 multiplier is provided with 8 pins, wherein pin X1 and pin X2 are the first input terminal, pin Y1 and pin Y2 are the second input terminal, pin +Vs and pin -VS are the power input terminals, and pin W and pin Z are the output terminals.

[0033] Optionally, see Figure 3 , Figure 3 1 is a schematic diagram of the structure of the second embodiment of the power amplifier output power control circuit of the present application. Figure 3 As shown, in this embodiment, the power amplifier current input circuit 21 includes a first resistor R1, a first end of the first resistor R1 is connected to the power supply 10, a second end of the first resistor R1 is connected to the input end of the power amplifier, and a first input end of the multiplier 23 is respectively connected to the first end and the second end of the first resistor R1 for obtaining a first voltage.

[0034] Alternatively, if Figure 3As shown, in this embodiment, the power amplifier voltage input circuit 22 includes a second resistor R2 and a third resistor R3, the first end of the second resistor R2 is connected to the input end of the power amplifier; the first end of the third resistor R3 is connected to the second end of the second resistor R2, and the second end of the third resistor R3 is grounded; the second input end of the multiplier 23 is connected to the second end of the second resistor R2 for obtaining the second voltage.

[0035] Optionally, based on Figure 3 In the embodiment, in the present embodiment, the resistance value of the second resistor and the resistance value of the third resistor are greater than the resistance value of the first resistor.

[0036] Specifically, Figure 3 As shown, let the first voltage be U x , the second voltage is U y , the feedback voltage is V o Based on the principle of the multiplier 23, it can be obtained that: Vo = Ux*Uy.

[0037] Among them, based on Figure 3 As can be seen from the circuit diagram of the power amplifier current input circuit 21, the first voltage U x =I pa *R1, where R1 is the resistance of the first resistor, I pa is the current at the input of the power amplifier.

[0038] Among them, based on Figure 3 As can be seen from the circuit diagram of the power amplifier voltage input circuit 22, the second voltage Wherein, R2 is the resistance value of the second resistor, R3 is the resistance value of the third resistor, V pa is the voltage at the input of the power amplifier.

[0039] In addition, since the resistance of the second resistor and the third resistor are greater than the resistance of the first resistor, when calculating the second voltage U y , the resistance of the first resistor can be ignored, so the voltage V at the input of the power amplifier pa Approximately the voltage V of the power supply 10 bat Therefore, when calculating the second voltage, the voltage V of the power supply 10 is directly used. bat Calculate, that is

[0040] When obtaining the first voltage U x and the second voltage U y After that, the feedback voltage Vo can be obtained, where the feedback voltage

[0041] In this embodiment, R 1 , R 2 and R 3 are all constants. If Then the feedback voltage Vo=k*(I pa *V bat ). As mentioned above, the feedback voltage Vo and the voltage V bat With current I pa Therefore, the power amplifier power consumption can be equivalent to the output power of the power amplifier by utilizing the characteristic that the power amplifier efficiency remains almost unchanged when the voltage and current of the power amplifier do not change much, and the power amplifier can be controlled accordingly.

[0042] Optionally, see Figure 4 , Figure 4 1 is a schematic diagram of the structure of the third embodiment of the power amplifier output power control circuit of the present application. Figure 4 As shown, in this embodiment, the comparison circuit 30 includes a comparator 31, a first input terminal of the comparator 31 is connected to the output terminal of the multiplier 23 and receives a feedback voltage, and a second input terminal of the comparator 31 receives a reference voltage APC; wherein the comparator 31 generates a control voltage based on a comparison between the reference voltage APC and the feedback voltage and outputs the control voltage to the control terminal of the power amplifier to control the power amplifier.

[0043] Optionally, in this embodiment, the comparison circuit 30 further includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7 and a capacitor C.

[0044] like Figure 4 As shown, the fourth resistor R4 is used to receive a reference voltage and is connected to the second input terminal of the comparator 31; the first end of the fifth resistor R5 is connected to the output terminal of the multiplier 23, and the second end of the fifth resistor R5 is connected to the first input terminal of the comparator 31; the sixth resistor R6 and the capacitor C are connected in parallel at the first input terminal of the comparator 31 and the output terminal of the comparator 31, the first end of the seventh resistor R7 is connected to the output terminal of the comparator 31, and the second end of the seventh resistor R7 is used to output a control voltage.

[0045] Alternatively, if Figure 4 As shown, the comparison circuit 30 also includes a first voltage regulator tube 32 and a second voltage regulator tube 33. The first end of the first voltage regulator tube 32 is grounded, and the second end of the first voltage regulator tube 32 is connected to the first input end of the comparator 31; the first end of the second voltage regulator tube 33 is grounded, and the second end of the second voltage regulator tube 33 is connected to the output end of the comparator 31.

[0046] In this embodiment, the first voltage regulator tube 32 is used to perform voltage stabilization compensation on the reference voltage APC, and the second voltage regulator tube 33 is used to perform voltage stabilization and filtering processing on the control voltage.

[0047] Alternatively, if Figure 4As shown, the comparison circuit 30 includes a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a capacitor C, a first voltage regulator tube 32 and a second voltage regulator tube 33. At this time, the second end of the second voltage regulator tube 33 is connected to the second end of the seventh resistor R7.

[0048] Different from the prior art, the power amplifier output power control circuit 100 of the present application includes a multiplication circuit 20 and a comparison circuit 30. The multiplication circuit 20 is connected to the power supply 10 and the input end of the power amplifier, and is used to generate a feedback voltage based on the voltage and current of the input end of the power amplifier. The comparison circuit 30 is connected to the multiplication circuit 20, and is used to generate a control voltage based on the feedback voltage and the reference voltage to control the power amplifier, so that the output power of the power amplifier is maintained stable. In the above manner, the power amplifier output power control circuit 100 of the present application can utilize the characteristic that the power amplifier efficiency is almost unchanged when the power amplifier voltage and current do not change much, and equate the power amplifier power consumption to the power amplifier output power, and then use the power amplifier output power to control the power amplifier, so that the output power of the power amplifier is maintained stable, ensuring that when any variable changes, the power amplifier automatically links to control the voltage change, so that the output power of the power amplifier is stably controlled.

[0049] In addition, the circuit structure of the present application is simple, and the debugging parameters are clear, which can greatly simplify the power debugging operation. The present application also introduces the product of the power amplifier voltage and current, that is, the power amplifier DC power consumption, for feedback control, which not only realizes the stable control of the current, but also realizes the stable control of the transmission power, efficiency or heat dissipation power under the change of the power amplifier supply voltage, which greatly improves the product performance. The present application can also reduce power consumption, reduce system design costs and reduce equipment temperature. When various loads are connected, the current can be kept stable, which is of great value to some specific fields that require current stability.

[0050] Optionally, the present application further proposes a radio frequency power amplifier circuit, see Figure 5 , Figure 5 1 is a schematic diagram of the structure of an embodiment of the radio frequency power amplifier circuit of the present application. Figure 5 As shown, the RF power amplifier circuit 200 of this embodiment includes a power supply 10, a power amplifier output power control circuit 100 and a power amplifier 110. The comparison circuit 30 is connected to the power amplifier 110 and is used to output a control voltage to the control end of the power amplifier 110 to maintain the output power of the power amplifier 110 stable.

[0051] Optionally, the present application further proposes a communication device, see Figure 6 , Figure 6 1 is a schematic diagram of the structure of an embodiment of the communication device of the present application. Figure 6 As shown, the communication device 300 of this embodiment includes the above-mentioned radio frequency power amplifier circuit 200. The communication device 300 may be a walkie-talkie or other digital media receiver, which is not limited here.

[0052] The above descriptions are merely embodiments of the present application and are not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A power amplifier output power control circuit, characterized in that: It includes a multiplication circuit and a comparison circuit. The multiplication circuit is connected to a power supply and an input terminal of a power amplifier and is used to generate a feedback voltage based on a voltage and a current at the input terminal of the power amplifier. The comparison circuit is connected to the multiplication circuit and is used to generate a control voltage based on the feedback voltage and a reference voltage to control the power amplifier so that the output power of the power amplifier remains stable.

2. The power amplifier output power control circuit according to claim 1, characterized in that: The multiplication circuit comprises: Multiplier; A power amplifier current input circuit, the power amplifier current input circuit is connected to the power supply, the input end of the power amplifier and the first input end of the multiplier, and the multiplier is used to obtain a first voltage across the power amplifier current input circuit; A power amplifier voltage input circuit, the power amplifier voltage input circuit is connected to the input terminal of the power amplifier and the second input terminal of the multiplier, and is used to output a second voltage to the multiplier based on the voltage of the input terminal of the power amplifier; The multiplier is used to calculate the product of the first voltage and the second voltage to obtain the feedback voltage.

3. The power amplifier output power control circuit according to claim 2, characterized in that: The power amplifier current input circuit comprises: A first resistor, wherein a first end of the first resistor is connected to the power supply, a second end of the first resistor is connected to an input end of the power amplifier, and a first input end of the multiplier is respectively connected to a first end and a second end of the first resistor for obtaining the first voltage.

4. The power amplifier output power control circuit according to claim 3, characterized in that: The power amplifier voltage input circuit comprises: a second resistor, wherein a first end of the second resistor is connected to an input end of the power amplifier; a third resistor, a first end of the third resistor being connected to a second end of the second resistor, and a second end of the third resistor being grounded; The second input terminal of the multiplier is connected to the second end of the second resistor for obtaining the second voltage.

5. The power amplifier output power control circuit according to claim 4, characterized in that: The resistance of the second resistor and the resistance of the third resistor are greater than the resistance of the first resistor.

6. The power amplifier output power control circuit according to claim 3, wherein the comparison circuit comprises: A comparator, wherein a first input terminal of the comparator is connected to the output terminal of the multiplier and receives the feedback voltage, and a second input terminal of the comparator receives a reference voltage; The comparator generates the control voltage based on the comparison between the reference voltage and the feedback voltage and outputs the control voltage to the control terminal of the power amplifier to control the power amplifier.

7. The power amplifier output power control circuit according to claim 6, characterized in that: The comparison circuit further comprises: A first voltage regulator tube, wherein a first end of the first voltage regulator tube is grounded, and a second end of the first voltage regulator tube is connected to a first input end of the comparator; A second voltage regulator tube, wherein a first end of the second voltage regulator tube is grounded, and a second end of the second voltage regulator tube is connected to the output end of the comparator.

8. The power amplifier output power control circuit according to claim 6, characterized in that: The comparison circuit further includes a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a capacitor; The fourth resistor is used to receive the reference voltage and is connected to the second input terminal of the comparator; the first end of the fifth resistor is connected to the output terminal of the multiplier, and the second end of the fifth resistor is connected to the first input terminal of the comparator; the sixth resistor and the capacitor are connected in parallel between the first input terminal of the comparator and the output terminal of the comparator, the first end of the seventh resistor is connected to the output terminal of the comparator, and the second end of the seventh resistor is used to output the control voltage.

9. A radio frequency power amplifier circuit, characterized in that: It comprises a power supply, a power amplifier and the power amplifier output power control circuit as described in any one of claims 1-8, wherein the comparison circuit is connected to the power amplifier and is used to output the control voltage to the control end of the power amplifier to maintain the output power of the power amplifier stable.

10. A communication device, characterized in that: Including the radio frequency power amplifier circuit as described in claim 9.

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