Power amplifier and its DEVM improvement circuit, corresponding WIFI system

Abstract

This invention belongs to the field of radio frequency amplifier technology, specifically disclosing a power amplifier and its DEVM improvement circuit, and a corresponding WIFI system. The power amplifier DEVM improvement circuit consists of a transient current control circuit, a transient current extraction circuit, a reference bias generation circuit, and a proportional amplifier circuit connected in series. The power amplifier includes the aforementioned power amplifier DEVM improvement circuit and amplification stage circuit, and the WIFI system includes the aforementioned power amplifier. Based on the idea of ​​increasing the initial operating current of the power amplifier, this invention proposes a transient overshoot voltage generation circuit. Using a current extraction method, the bias voltage of the power amplifier is instantaneously increased in the initial state of amplifier operation and then slowly decreased, thereby increasing the initial gain of the amplifier, compensating for the output power in the initial stage, and improving the power amplifier DEVM. This invention is applicable to improving the DEVM of power amplifiers in WiFi radio frequency front-end modules.

Description

Technical Field

[0001] This invention belongs to the field of radio frequency amplifier technology, and relates to a power amplifier and its DEVM improvement circuit, and a corresponding WIFI system. Background Technology

[0002] The WiFi RF front-end module is one of the important modules in a WiFi transceiver system. It mainly includes a power amplifier, a low-noise amplifier, and switching circuits. To reduce the bit error rate, WiFi systems impose extremely high linearity requirements on the power amplifier, and the dynamic vector amplitude error (DEVM) is a crucial indicator of linearity in WiFi power amplifiers.

[0003] In actual operation, to save power, the power amplifier of a WiFi system operates in time-division duplex (TDD) mode, meaning it operates in a periodic switching state with a fixed duty cycle. The transient electrothermal effect generated by the dynamic switching of the power amplifier causes a slow power ramp-up in the initial switching state, such as... Figure 1 As shown, this phenomenon leads to a severe deterioration of the amplifier's DEVM. Therefore, it is crucial to compensate for the output power during the initial stage of the power amplifier and maintain a constant output power throughout the amplifier's dynamic operating period.

[0004] How to compensate for the initial power value of a power amplifier during dynamic operation and maintain a constant output power during the dynamic operation period has always been a research hotspot. Chinese invention patent application CN113162557A discloses a DEVM compensation circuit and a power amplifier for a power amplifier. In the initial state of operation of the power amplifier, transient additional power is injected into the input terminal through an RF switch to compensate for the output power in the initial stage. However, this increases the difficulty of input matching circuit design. Summary of the Invention

[0005] The purpose of this invention is to provide a power amplifier DEVM improvement circuit to increase the amplifier's initial gain, compensate for the output power in the initial stage, and improve the phenomenon of slow rise in the amplifier's power-time relationship curve in the initial stage.

[0006] A second objective of the present invention is to provide a power amplifier that includes the above-described power amplifier dynamic DEVM improvement circuit;

[0007] A third objective of this invention is to provide a WIFI system comprising the aforementioned power amplifier.

[0008] To achieve the above objectives, the technical solution adopted by this invention is as follows:

[0009] A power amplifier DEVM improvement circuit consists of a transient current control circuit, a transient current extraction circuit, a reference bias generation circuit, and a proportional amplifier circuit.

[0010] A reference voltage is input to the first input terminal of the transient current control circuit, and a first enable signal is input to the second input terminal of the transient current control circuit. The transient current control circuit generates a first current according to the reference voltage and controls the direction of the first current according to the first enable signal.

[0011] The input terminal of the transient current extraction circuit is connected to the output terminal of the transient current control circuit to receive the first current output by the transient current control circuit; the transient current extraction circuit outputs a second current and controls the magnitude of the second current according to the first current.

[0012] The output of the transient current extraction circuit is connected to the input of the reference bias generation circuit, and the generated second current is output to the reference bias generation circuit. The reference bias generation circuit generates a changing first voltage according to the change of the second current and outputs it to the proportional amplifier circuit.

[0013] The first input terminal of the proportional amplifier circuit receives a second enable signal; the second input terminal of the proportional amplifier circuit is connected to the output terminal of the reference bias generation circuit to input a first voltage; the proportional amplifier circuit amplifies the first voltage according to the proportional coefficient to generate a second voltage and outputs it to the externally connected power amplifier, while controlling its own turn-on and turn-off according to the second enable signal.

[0014] As a limitation, the transient current control circuit consists of a first operational amplifier and an enable transistor;

[0015] The non-inverting input of the first operational amplifier is the first input of the transient current control circuit, and the inverting input is connected to its own output. At the same time, its own output serves as the output of the transient current control circuit on one hand and is connected to the drain of the enable transistor on the other. The gate of the enable transistor is the second input of the transient current control circuit, and the source of the enable transistor is grounded. The positive power supply of the first operational amplifier is connected to the power supply, and the negative power supply is grounded.

[0016] As a further limitation, the transient current extraction circuit consists of a control transistor, a first capacitor, and a first resistor;

[0017] One end of the first capacitor serves as the input terminal of the transient current extraction circuit and is connected to the gate of the control transistor on the other end. The other end of the first capacitor is grounded. The source of the control transistor is connected to one end of the first resistor, and the other end of the first resistor is connected to the power supply voltage. The drain of the control transistor serves as the output terminal of the transient current extraction circuit.

[0018] As a second limitation, the reference bias generation circuit consists of a fixed current generation branch, a current injection branch, and a second resistor.

[0019] The input terminal of the fixed current generating branch serves as the input terminal of the reference bias generating circuit. The output terminal of the fixed current generating branch is connected to the output terminal of the current injection branch on one hand and to one end of the second resistor on the other hand, while the other end of the second resistor is grounded.

[0020] The common terminal of the fixed current generation branch, the current injection branch, and the second resistor is used as the output terminal of the reference bias generation circuit.

[0021] As a third limitation, the proportional amplifier circuit consists of a proportional operational amplifier, a third resistor, and a fourth resistor;

[0022] The non-inverting input of the proportional operational amplifier serves as the second input of the proportional amplifier circuit. The output of the proportional operational amplifier serves as the output of the proportional amplifier circuit on one hand, and is connected to one end of the third resistor on the other hand. The other end of the third resistor is grounded through the fourth resistor. The inverting input of the proportional operational amplifier is connected to the common terminal of the third and fourth resistors.

[0023] The enable terminal of the proportional operational amplifier serves as the first input terminal of the proportional amplifier circuit, the positive power supply terminal is connected to the power supply, and the negative power supply terminal is grounded.

[0024] The amplification factor of the proportional amplifier circuit is A = 1 + R3 / R4, where R3 is the resistance of the third resistor and R4 is the resistance of the fourth resistor.

[0025] A power amplifier includes the aforementioned power amplifier DEVM improvement circuit and an amplification stage circuit. The output terminal of the power amplifier DEVM improvement circuit is connected to the bias input terminal of the amplification stage circuit. The input matching network signal input terminal of the amplification stage circuit serves as the RF signal input terminal of the power amplifier, and the output matching network signal output terminal of the amplification stage circuit serves as the output terminal of the power amplifier.

[0026] A WIFI system includes the aforementioned power amplifier.

[0027] As a limitation, when the WIFI system is working in the receiving state, the first enable signal controls the first current to flow into the ground from inside the transient current control circuit, the transient current extraction circuit generates the second current in the receiving state and outputs it to the reference bias generation circuit, the reference bias generation circuit generates the first voltage in the receiving state and outputs it to the proportional amplifier circuit, and the second enable signal controls the output of the proportional amplifier circuit to be cut off.

[0028] At the instant the WIFI system switches from receiving mode to transmitting mode, the second enable signal controls the proportional amplifier circuit to turn on. The proportional amplifier circuit amplifies the first voltage of the receiving mode according to the proportional coefficient to generate a transient second voltage and outputs it to the power amplifier. At the same time, the first enable signal controls the first current to flow into the transient current extraction circuit. Under the control of the first current, the transient current extraction circuit gradually reduces the magnitude of the second current until the second current is 0. The reference bias generation circuit generates the first voltage of the transmitting mode and outputs it to the proportional amplifier circuit. The proportional amplifier circuit amplifies the first voltage of the transmitting mode according to the proportional coefficient to generate a transmitting second voltage and outputs it to the power amplifier.

[0029] At the instant the WIFI system switches from receiving mode to transmitting mode, the power amplifier switches to its initial operating state; the transient second voltage is greater than the second voltage of the transmitting mode.

[0030] The present invention, by adopting the above-described technical solution, achieves the following technical advancements compared to existing technologies:

[0031] (1) Based on the idea of ​​increasing the operating current of the power amplifier in the initial working state, this invention proposes a novel transient overshoot voltage generation circuit. It adopts the current extraction method to make the bias voltage of the power amplifier increase instantaneously in the initial state of the amplifier switching on and then decrease slowly, so as to improve the initial gain of the amplifier, compensate the output power in the initial stage, compensate the phenomenon of slow rise of the amplifier PVT curve in the initial stage, maintain a small output power fluctuation during the dynamic working period of the amplifier, and improve the DEVM of the power amplifier.

[0032] (2) The present invention provides a novel gate bias voltage generation structure that can improve the dynamic EVM of a power amplifier. It can compensate for the power value in the initial stage when the power amplifier frequently switches operation, thereby compensating for the phenomenon of slow rise in the power-time (PVT) curve in the initial stage of the power amplifier, thereby improving the dynamic EVM characteristics of the power amplifier.

[0033] In summary, the novel transient overshoot voltage generation circuit provided by this invention increases the amplifier bias voltage instantaneously at the initial state of the amplifier switching on, increases the initial current, compensates for the output power in the initial stage, maintains a small output power fluctuation during the dynamic operation period of the amplifier, and improves the DEVM of the power amplifier. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0035] In the attached diagram:

[0036] Figure 1This is an initial PVT curve of a power amplifier in the prior art of this invention;

[0037] Figure 2 This is a circuit schematic diagram of Embodiment 1 of the present invention;

[0038] Figure 3 The circuit diagram for Embodiment 1 of the present invention is shown in detail.

[0039] Figure 4 This is a circuit schematic diagram of Embodiment 2 of the present invention;

[0040] Figure 5 The circuit diagram for Embodiment 2 of the present invention is shown in detail.

[0041] Figure 6 This is a schematic diagram of the dynamic EVM improvement circuit for the WIFI system receiver circuit in Embodiment 3 of the present invention.

[0042] Figure 7 This is a schematic diagram of the dynamic EVM improvement circuit for the WIFI system transmitter circuit in Embodiment 3 of the present invention.

[0043] Figure 8 This is a timing diagram showing the bias voltage variation of the power amplifier in the WIFI system in Embodiment 3 of the present invention. Detailed Implementation

[0044] The preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustrative and explanatory purposes only and are not intended to limit the scope of the invention.

[0045] Example 1: A power amplifier DEVM improvement circuit

[0046] like Figure 2 and Figure 3 As shown, this embodiment consists of a transient current control circuit, a transient current extraction circuit, a reference bias generation circuit, and a proportional amplifier circuit.

[0047] The first input terminal of the transient current control circuit receives the reference voltage V. REF The second input terminal of the transient current control circuit receives the first enable signal R. EN The transient current control circuit is based on the reference voltage V. REF Generate the first current I OP1 And according to the first enable signal R EN Control the first current I OP1 The direction of flow.

[0048] The input terminal of the transient current extraction circuit is connected to the output terminal of the transient current control circuit to receive the first current I output by the transient current control circuit. OP1The transient current extraction circuit outputs a second current I. tran And according to the first current I OP1 Control the second current I tran Size.

[0049] The output of the transient current extraction circuit is connected to the input of the reference bias generation circuit, and the generated second current I... tran The output is sent to the reference bias generation circuit; the reference bias generation circuit generates the bias based on the second current I. tran The change produces a change in the first voltage V R It is then output to the proportional amplifier circuit.

[0050] The first input terminal of the proportional amplifier circuit receives the second enable signal T. EN The second input terminal of the proportional amplifier circuit is connected to the output terminal of the reference bias generation circuit to receive the first voltage V. R The proportional amplifier circuit converts the first voltage V R The second voltage V is generated after amplification based on the proportional coefficient. B It is then output to an externally connected power amplifier, and simultaneously according to the second enable signal T EN It controls its own on / off state.

[0051] Specifically, such as Figure 2 and Figure 3 As shown, the transient current control circuit consists of a first operational amplifier OP1 and an enable transistor NM. EN Composition. The non-inverting input of the first operational amplifier OP1 is the first input of the transient current control circuit, and the inverting input is connected to its own output. Simultaneously, its own output serves as both the output of the transient current control circuit and the output of the enable transistor NM. EN The drains are connected, enabling the NM transistor. EN The gate of the transistor is the second input terminal of the transient current control circuit, enabling the transistor NM. EN The source of the first operational amplifier OP1 is grounded, and its positive power supply terminal is connected to the power supply while its negative power supply terminal is grounded.

[0052] The transient current extraction circuit consists of a control transistor PM1, a first capacitor C1, and a first resistor R1. One end of the first capacitor C1 serves as the input terminal of the transient current extraction circuit and is connected to the gate of the control transistor PM1 on the other end. The other end of the first capacitor C1 is grounded. The source of the control transistor PM1 is connected to one end of the first resistor R1, and the other end of the first resistor R1 is connected to the power supply voltage. The drain of the control transistor PM1 serves as the output terminal of the transient current extraction circuit.

[0053] The reference bias generation circuit consists of a fixed current generation branch, a current injection branch, and a second resistor R2. The input terminal of the fixed current generation branch serves as the input terminal of the reference bias generation circuit. The output terminal of the fixed current generation branch is connected to both the output terminal of the current injection branch and one end of the second resistor R2, with the other end of R2 grounded. The common terminal of the fixed current generation branch, the current injection branch, and the second resistor R2 serves as the output terminal of the reference bias generation circuit. In this embodiment, the current injection branch generates a fixed current I through its included current mirror. con .

[0054] The proportional amplifier circuit consists of a proportional operational amplifier OP2, a third resistor R3, and a fourth resistor R4. The non-inverting input of the proportional operational amplifier OP2 serves as the second input of the proportional amplifier circuit. The output of the proportional operational amplifier OP2 serves as the output of the proportional amplifier circuit and is connected to one end of the third resistor R3. The other end of the third resistor R3 is grounded through the fourth resistor R4. The inverting input of the proportional operational amplifier OP2 is connected to the common terminal of the third resistor R3 and the fourth resistor R4.

[0055] The enable terminal of the proportional operational amplifier OP2 serves as the first input terminal of the proportional amplifier circuit, the positive power supply terminal is connected to the power supply, and the negative power supply terminal is grounded.

[0056] The amplification factor of the proportional amplifier circuit is A = 1 + R3 / R4, where R3 is the resistance of the third resistor R3 and R4 is the resistance of the fourth resistor R4.

[0057] In this embodiment, the reference voltage V REF Provided by the bandgap reference, enabling transistor NM EN An NMOS transistor is used, while the control transistor PM1 is a PMOS transistor.

[0058] Example 2: A power amplifier

[0059] like Figure 4 As shown, this embodiment includes the power amplifier DEVM improvement circuit provided in Embodiment 1, and also includes an amplification stage circuit; the output terminal of the power amplifier DEVM improvement circuit is connected to the bias input terminal of the amplification stage circuit.

[0060] The amplifier stage circuit consists of an amplifier transistor Q1, an input matching network, and an output matching network. The input signal input terminal of the amplifier stage circuit serves as the RF signal input terminal of the power amplifier, the output signal output terminal of the amplifier stage circuit serves as the output terminal of the power amplifier, and the base of the amplifier transistor Q1 serves as the bias input terminal of the amplifier stage circuit.

[0061] Example 3: A WIFI System

[0062] This embodiment includes the power amplifier provided in Embodiment 2. The power amplifier provided in Embodiment 2 is used in the WiFi radio frequency front-end module of the WIFI system to linearly amplify small signals.

[0063] Combination Figures 5-7 Here's an explanation of how this embodiment works: When the WIFI system is in receiving mode, the first enable signal R... EN Control the first current I OP1 The transient current flows into ground from within the transient current control circuit, and the transient current extraction circuit generates a second current I in the receiving state. tran It is then output to the reference bias generation circuit, which generates the first voltage V for the receiving state. R And output to the proportional amplifier circuit, the second enable signal T EN The output of the proportional amplifier circuit is cut off. The second enable signal T is activated the instant the WIFI system switches from receive mode to transmit mode. EN The proportional amplifier circuit is turned on, and the proportional amplifier circuit receives the first voltage V from the state. R The transient second voltage V is generated after amplification based on the proportional coefficient. B And output to the power amplifier; simultaneously, the first enable signal R EN Control the first current I OP1 The transient current flows into the transient current extraction circuit, and the transient current extraction circuit is in the first current I OP1 Under control, gradually reduce the second current I tran When the magnitude of the second current is zero, the reference bias generation circuit generates the first voltage V for the emission state. R It is then output to a proportional amplifier circuit, which outputs the first voltage V from the emission state. R The second voltage V generated after amplification by the proportional coefficient is used to produce the emission state. B The output is then sent to the power amplifier. The power amplifier switches to its initial operating state the instant the WIFI system switches from receiving to transmitting; the difference between the transient second voltage and the second voltage in the transmitting state is ΔV. B .

[0064] Specifically: enable transistor NM EN Gate enable signal R EN When the signal is "high", the WiFi system receiver operates; when it is "low", the WiFi system transmitter operates. The transient current extraction circuit uses the transient branch current, i.e., the second current I. tran =(V C -V SG1 The first voltage at the output of the reference bias generation circuit is V / R1. R =(I tran +I con )R con , where Rcon Let R2 be the resistance value of the second resistor.

[0065] like Figure 6 When the WiFi system is in receiving mode, the transient current control circuit operates normally, and the first enable signal R... EN To enable transistor NM (high), EN When in the ON state, the first current I supplied to the output terminal of the first operational amplifier OP1 is... OP1 All flow into enable transistor NM EN In the transient current extraction circuit, the gate voltage of the control transistor PM1 is "low," the transistor is normally turned on, the transient current extraction circuit is turned on, and the second current I... tran =(V C -V SG1 R1 is injected into the reference bias generation circuit. The reference bias generation circuit has a fixed current I. con Provided by the current mirror, the first voltage V generated at this time R =(I tran +I con )R con At this time, the input voltage at the second input terminal of the proportional amplifier circuit is (I... tran +I con )R con The second enable signal T EN When the value is "low", the proportional operational amplifier OP2 is in the off state, the bias voltage of the amplifier stage circuit is 0, and the power amplifier is in the cutoff state.

[0066] like Figure 7 As shown, when the WiFi system switches to the transmission mode, at the instant of switching to the transmission mode, the second enable signal T... EN When the signal is "high", the proportional operational amplifier OP2 is turned on. After passing through the proportional resistor network, the output bias voltage, i.e., the second voltage V, is generated. B =A(I tran +I con )R con A is the proportional operational amplifier gain. Simultaneously, the first enable signal R... EN Change to "low" to enable transistor NM EN When turned off, the first current I output by the first operational amplifier OP1 is... OP1 With no path to ground, charging begins on the first capacitor C1. The voltage across the first capacitor C1 is the gate voltage V of the control transistor PM1. G1 Continues to increase. Due to I tran =(V C -V SG1 -V G1 Therefore, the second current I in the transient current extraction circuit is ) / R1. tran Continue to decrease until the gate voltage V of control tube PM1 is reduced.G1 The voltage is increased until the control transistor PM1 is turned off. At this point, no current generated by the transient current extraction circuit flows into the reference bias generation circuit, thus completing one current extraction cycle. The first voltage generated by the fixed current generation branch is now V. R =I con R con The input voltage of the proportional amplifier circuit is I. con R con The output bias voltage, i.e., the second voltage, is V. B =AI con R con That is, in the initial state when the power amplifier switches on, the power amplifier gate voltage V B From A(I tran +I con )R con Reduce to AI con R con This is equivalent to generating an AI amplitude. tran R con Overshoot voltage.

[0067] Figure 8 The timing diagram of the power amplifier bias voltage during the transition from the receiving to the transmitting state of the WiFi system is presented. As can be seen from the diagram, the transient overshoot voltage generation circuit used in this embodiment, namely the power amplifier DEVM improvement circuit provided in Embodiment 1, generates an overshoot voltage effect on the power amplifier bias circuit in the initial state of power amplifier operation by extracting transient current. The overshoot voltage value ΔV B =AI tran R con This improved the power amplifier gain, compensated for the initial output power, and compensated for the slow rise of the power amplifier's PVT curve in the initial stage, thereby improving the power amplifier's DEVM.

Claims

1. A power amplifier DEVM improvement circuit, characterized in that, It consists of a transient current control circuit, a transient current extraction circuit, a reference bias generation circuit, and a proportional amplifier circuit; A reference voltage is input to the first input terminal of the transient current control circuit, and a first enable signal is input to the second input terminal of the transient current control circuit. The transient current control circuit generates a first current according to the reference voltage and controls the direction of the first current according to the first enable signal. The input terminal of the transient current extraction circuit is connected to the output terminal of the transient current control circuit to receive the first current output by the transient current control circuit. The transient current extraction circuit outputs a second current and controls the magnitude of the second current based on the first current. The output of the transient current extraction circuit is connected to the input of the reference bias generation circuit, and the generated second current is output to the reference bias generation circuit. The reference bias generation circuit generates a changing first voltage according to the change of the second current and outputs it to the proportional amplifier circuit. The first input terminal of the proportional amplifier circuit receives the second enable signal; The second input terminal of the proportional amplifier circuit is connected to the output terminal of the reference bias generation circuit to input the first voltage; The proportional amplifier circuit amplifies the first voltage according to the proportional coefficient to generate a second voltage and outputs it to the externally connected power amplifier. At the same time, it controls its own turn-on and turn-off according to the second enable signal.

2. The power amplifier DEVM improvement circuit according to claim 1, characterized in that, The transient current control circuit consists of a first operational amplifier and an enable transistor; The non-inverting input of the first operational amplifier is the first input of the transient current control circuit, and the inverting input is connected to its own output. At the same time, its own output serves as the output of the transient current control circuit on one hand and is connected to the drain of the enable transistor on the other. The gate of the enable transistor is the second input of the transient current control circuit, and the source of the enable transistor is grounded. The positive power supply of the first operational amplifier is connected to the power supply, and the negative power supply is grounded.

3. The power amplifier DEVM improvement circuit according to claim 2, characterized in that, The transient current extraction circuit consists of a control transistor, a first capacitor, and a first resistor; One end of the first capacitor serves as the input terminal of the transient current extraction circuit and is connected to the gate of the control transistor on the other end. The other end of the first capacitor is grounded. The source of the control transistor is connected to one end of the first resistor, and the other end of the first resistor is connected to the power supply voltage. The drain of the control transistor serves as the output terminal of the transient current extraction circuit.

4. The power amplifier DEVM improvement circuit according to any one of claims 1-3, characterized in that, The reference bias generation circuit consists of a fixed current generation branch, a current injection branch, and a second resistor. The input terminal of the fixed current generating branch serves as the input terminal of the reference bias generating circuit. The output terminal of the fixed current generating branch is connected to the output terminal of the current injection branch on one hand and to one end of the second resistor on the other hand, while the other end of the second resistor is grounded. The common terminal of the fixed current generation branch, the current injection branch, and the second resistor is used as the output terminal of the reference bias generation circuit.

5. The power amplifier DEVM improvement circuit according to any one of claims 1-3, characterized in that, The proportional amplifier circuit consists of a proportional operational amplifier, a third resistor, and a fourth resistor; The non-inverting input of the proportional operational amplifier serves as the second input of the proportional amplifier circuit. The output of the proportional operational amplifier serves as the output of the proportional amplifier circuit on one hand, and is connected to one end of the third resistor on the other hand. The other end of the third resistor is grounded through the fourth resistor. The inverting input of the proportional operational amplifier is connected to the common terminal of the third and fourth resistors. The enable terminal of the proportional operational amplifier serves as the first input terminal of the proportional amplifier circuit, the positive power supply terminal is connected to the power supply, and the negative power supply terminal is grounded. The amplification factor of the proportional amplifier circuit is A = 1 + R3 / R4, where R3 is the resistance of the third resistor and R4 is the resistance of the fourth resistor.

6. A power amplifier, characterized in that, The power amplifier DEVM improvement circuit according to any one of claims 1-5 further includes an amplification stage circuit; the output terminal of the power amplifier DEVM improvement circuit is connected to the bias input terminal of the amplification stage circuit, the input matching network signal input terminal of the amplification stage circuit serves as the RF signal input terminal of the power amplifier, and the output matching network signal output terminal of the amplification stage circuit serves as the output terminal of the power amplifier.

7. A WIFI system, characterized in that, Includes the power amplifier as described in claim 6.

8. The WIFI system according to claim 7, characterized in that, When the WIFI system is in the receiving state, the first enable signal controls the first current to flow into the ground from inside the transient current control circuit. The transient current extraction circuit generates the second current in the receiving state and outputs it to the reference bias generation circuit. The reference bias generation circuit generates the first voltage in the receiving state and outputs it to the proportional amplifier circuit. The second enable signal controls the output of the proportional amplifier circuit to be cut off. At the instant the WIFI system switches from receiving mode to transmitting mode, the second enable signal controls the proportional amplifier circuit to turn on. The proportional amplifier circuit amplifies the first voltage of the receiving mode according to the proportional coefficient to generate a transient second voltage and outputs it to the power amplifier. At the same time, the first enable signal controls the first current to flow into the transient current extraction circuit. Under the control of the first current, the transient current extraction circuit gradually reduces the magnitude of the second current until the second current is 0. The reference bias generation circuit generates the first voltage of the transmitting mode and outputs it to the proportional amplifier circuit. The proportional amplifier circuit amplifies the first voltage of the transmitting mode according to the proportional coefficient to generate a transmitting second voltage and outputs it to the power amplifier. The moment the WIFI system switches from receiving mode to transmitting mode, the power amplifier switches to its initial operating state. The transient second voltage is greater than the second voltage in the emission state.

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