阅读说明：本技术 一种射频功率放大器幅度调制对幅度调制的补偿电路 (Compensation circuit for amplitude modulation of radio frequency power amplifier ) 是由 奕江涛 苏强 温华东 于 2019-09-26 设计创作，主要内容包括：本申请实施例提供一种射频功率放大器幅度调制对幅度调制的补偿电路,所述射频功率放大器幅度调制对幅度调制的补偿电路包括：第一偏置电路、功率放大器、以及位于所述第一偏置电路和所述功率放大器之间的补偿电路；其中,所述补偿电路包括二极管检波电路和前馈放大器,用于对幅度调制对幅度调制AM-AM失真进行补偿。(The embodiment of the application provides a compensation circuit of amplitude modulation of a radio frequency power amplifier, and the compensation circuit of amplitude modulation of the radio frequency power amplifier comprises: a first bias circuit, a power amplifier, and a compensation circuit between the first bias circuit and the power amplifier; the compensation circuit comprises a diode detection circuit and a feed-forward amplifier and is used for compensating amplitude modulation AM-AM distortion for amplitude modulation.)

1. A circuit for compensating amplitude modulation to amplitude modulation of a radio frequency power amplifier is characterized by comprising: a first bias circuit, a power amplifier, and a compensation circuit between the first bias circuit and the power amplifier; wherein the content of the first and second substances,

the compensation circuit comprises a diode detection circuit and a feed-forward amplifier and is used for compensating amplitude modulation AM-AM distortion for amplitude modulation.

2. The amplitude modulation versus amplitude modulation compensation circuit for a radio frequency power amplifier according to claim 1, wherein the diode detector circuit comprises: a first transistor and a first resistor connected in parallel with the first transistor; wherein the content of the first and second substances,

the grid electrode and the drain electrode of the first transistor are in short circuit and are connected with the first bias circuit; the source of the first transistor is connected with the first end of the power amplifier, and the first end of the power amplifier is the grid of the second transistor in the power amplifier.

3. The amplitude modulation to amplitude modulation compensation circuit of a radio frequency power amplifier of claim 1, wherein the feed forward amplifier comprises: a first capacitor, a third transistor and a second capacitor; wherein the content of the first and second substances,

a first end of the first capacitor is connected with a radio frequency input end, and a second end of the first capacitor is connected with a grid electrode of the third transistor; the source of the third transistor is connected with the ground end, the drain of the third transistor is connected with the first end of the second capacitor, and the second end of the second capacitor is connected with the drain of the first transistor.

4. The amplitude modulation versus amplitude modulation compensation circuit for a radio frequency power amplifier of claim 3, wherein the feed forward amplifier further comprises a second bias circuit for providing a bias current to the third transistor; wherein the content of the first and second substances,

the second bias circuit is connected to a gate of the third transistor.

5. The amplitude modulation versus amplitude modulation compensation circuit of a radio frequency power amplifier according to claim 4, wherein the feed forward amplifier further comprises a voltage source and a second resistor connected in series with the voltage source for providing a drain bias voltage for the third transistor; wherein the second resistor is connected to a drain of the third transistor.

6. The amplitude modulation versus amplitude modulation compensation circuit for a radio frequency power amplifier as claimed in claim 2, wherein the first resistor in the diode detector circuit is a variable resistor.

7. The amplitude modulation versus amplitude modulation compensation circuit of a radio frequency power amplifier according to claim 4 or 5, wherein the amplification factor of the feed forward amplifier is an adjustable amplification factor.

8. The amplitude modulation to amplitude modulation compensation circuit of a radio frequency power amplifier of claim 7,

the parameter of the third transistor in the feed forward amplifier is adjustable; and/or the presence of a gas in the gas,

the parameters of the second bias circuit in the feed forward amplifier are adjustable.

9. The amplitude modulation versus amplitude modulation compensation circuit of a radio frequency power amplifier according to claim 8, wherein the second bias circuit has adjustable parameters, comprising at least:

the current parameter of the first current source in the second bias circuit is adjustable.

10. The amplitude modulation versus amplitude modulation compensation circuit for a radio frequency power amplifier according to claim 2, further comprising a circuit switch, wherein two terminals of the circuit switch are connected in parallel with two terminals of the first transistor.

11. The amplitude modulation versus amplitude modulation compensation circuit for a radio frequency power amplifier according to any one of claims 1 to 10,

the power amplifier comprises a second transistor; alternatively, the first and second electrodes may be,

the power amplifier includes a plurality of second transistors between which a stacked-tube structure is formed.

Technical Field

The application relates to the field of electronic circuits, in particular to a compensation circuit for amplitude modulation of a radio frequency power amplifier.

Background

In a mobile communication system, the efficiency and linear power of a front-end radio frequency power amplifier (power amplifier for short) directly affect the energy consumption and communication quality of a base station and terminal equipment, and the output power and Adjacent Channel Leakage Ratio (ACLR) index of an uplink modulation signal of the terminal equipment after being amplified by the front-end radio frequency power amplifier must meet the requirements of various mobile communication protocols. In a memory-effect-free system, the ACLR performance of a power amplifier can be characterized by Amplitude Modulation-Amplitude Modulation (AM-AM) distortion and Amplitude Modulation-Phase Modulation (AM-PM) distortion of the power amplifier. The larger the rate of change of the AM-AM distortion and the AM-PM distortion with the change of the input signal, the worse the ACLR of the output signal of the power amplifier. The source of AM-AM distortion is mainly that the transistor voltage input current output characteristic of the power amplifier exhibits nonlinear characteristic under the condition of large amplitude signal input, and as the input driving power of the power amplifier increases, the gain compression of the power amplifier occurs, which causes spectrum diffusion and ACLR deterioration.

Disclosure of Invention

In order to solve the above technical problem, an embodiment of the present application provides a compensation circuit for amplitude modulation to amplitude modulation of a radio frequency power amplifier.

The embodiment of the application provides a compensation circuit of amplitude modulation to amplitude modulation of a radio frequency power amplifier, which is characterized in that the compensation circuit of amplitude modulation to amplitude modulation of the radio frequency power amplifier comprises: a first bias circuit, a power amplifier, and a compensation circuit between the first bias circuit and the power amplifier; wherein the content of the first and second substances,

the compensation circuit comprises a diode detection circuit and a feed-forward amplifier and is used for compensating AM-AM distortion.

In an alternative embodiment of the present application, the diode detector circuit includes: a first transistor and a first resistor connected in parallel with the first transistor; wherein the content of the first and second substances,

the grid electrode and the drain electrode of the first transistor are in short circuit and are connected with the first bias circuit; the source of the first transistor is connected with the first end of the power amplifier, and the first end of the power amplifier is the grid of the second transistor in the power amplifier.

In an alternative embodiment of the present application, the feed forward amplifier comprises: a first capacitor, a third transistor and a second capacitor; wherein the content of the first and second substances,

a first end of the first capacitor is connected with a radio frequency input end, and a second end of the first capacitor is connected with a grid electrode of the third transistor; the source of the third transistor is connected with the ground end, the drain of the third transistor is connected with the first end of the second capacitor, and the second end of the second capacitor is connected with the drain of the first transistor.

In an alternative embodiment of the present application, the feed forward amplifier further comprises a second bias circuit for providing a bias current to the third transistor; wherein the content of the first and second substances,

the second bias circuit is connected to a gate of the third transistor.

In an alternative embodiment of the present application, the feed forward amplifier further comprises a voltage source, and a second resistor connected in series with the voltage source; wherein the content of the first and second substances,

the second resistor is connected with the drain electrode of the third transistor and is used for providing drain electrode bias voltage for the third transistor.

In an alternative embodiment of the present application, the first resistor in the diode detector circuit is a variable resistor.

In an alternative embodiment of the present application, the amplification factor of the feed forward amplifier is an adjustable amplification factor.

In an optional embodiment of the present application, a parameter of the third transistor in the feed forward amplifier is adjustable; and/or the presence of a gas in the gas,

the parameters of the second bias circuit in the feed forward amplifier are adjustable.

In an optional embodiment of the present application, the parameter of the second bias circuit is adjustable, and the second bias circuit at least includes:

the current parameter of the first current source in the second bias circuit is adjustable.

In an optional embodiment of the present application, the compensation circuit further includes a circuit switch, and two ends of the circuit switch are connected in parallel with two ends of the first transistor.

In an alternative embodiment of the present application, the power amplifier includes a second transistor; alternatively, the first and second electrodes may be,

the power amplifier includes a plurality of second transistors between which a stacked-tube structure is formed.

In the technical solution of the embodiment of the present application, a compensation circuit for amplitude modulation of a radio frequency power amplifier includes: a first bias circuit, a power amplifier, and a compensation circuit between the first bias circuit and the power amplifier; the compensation circuit comprises a diode detection circuit and a feed-forward amplifier and is used for compensating AM-AM distortion. By adopting the technical scheme of the embodiment of the application, the compensation circuit is introduced in front of the power amplifier, and the diode detection circuit in the compensation circuit can realize that the gain compression caused by the AM-AM distortion is compensated by improving the bias current (voltage) of the power amplifier under the condition that the amplitude of the input signal of the power amplifier is increased. On the other hand, the requirement of the mobile communication protocol on the set-up time of the power amplifier can be met by the feed-forward amplifier in the compensation circuit. The radio frequency power amplifier amplitude modulation of the embodiment of the application is relatively simple to realize the amplitude modulation compensation circuit, flexible in design, good in applicability, easy to integrate and low in cost, and AMAM programming can be adjusted by adjusting parameters in the compensation circuit.

Drawings

FIG. 1 is a circuit schematic diagram of an AM-AM compensation circuit based on diode detection;

FIG. 2 is a schematic diagram comparing an original circuit with an AM-AM compensation circuit;

FIG. 3 is a schematic diagram showing the variation of the Vin DC level with the input power Pin in the AM-AM compensation circuit shown in FIG. 1;

FIG. 4 is a schematic diagram of the effect of gain compression compensation based on the AM-AM compensation circuit shown in FIG. 1;

fig. 5 is a schematic structural diagram of a compensation circuit for amplitude modulation to amplitude modulation of the rf power amplifier according to an embodiment of the present application;

fig. 6 is a first circuit schematic diagram of a compensation circuit for amplitude modulation versus amplitude modulation of a radio frequency power amplifier according to an embodiment of the present application;

fig. 7 is a second circuit schematic diagram of a compensation circuit for amplitude modulation to amplitude modulation of the rf power amplifier according to an embodiment of the present application;

fig. 8 is a third circuit schematic diagram of a compensation circuit for amplitude modulation to amplitude modulation of the rf power amplifier according to an embodiment of the present application;

fig. 9 is a fourth circuit schematic diagram of a compensation circuit for amplitude modulation versus amplitude modulation of the rf power amplifier according to an embodiment of the present application;

fig. 10 is a fifth circuit schematic diagram of a circuit for compensating amplitude modulation versus amplitude modulation of a radio frequency power amplifier according to an embodiment of the present application.

Detailed Description

In order to facilitate understanding of the technical solutions of the embodiments of the present application, the following description is made of related art of the embodiments of the present application.

When designing an amplifier, the difference from the linear power (undistorted or weakly distorted power) to the saturated power of the power amplifier is determined according to the Peak-to-Average Ratio (PAR) value (the Ratio of the Peak power with the occurrence probability of 0.01% to the total Average power) of the non-constant envelope modulated signal adopted by the mobile communication system. The selection of the difference value needs to make compromise between the ACLR performance and the efficiency of the power amplifier; if the value is too large, the load impedance of the amplifier is generally required to be reduced to realize the effect, the ACLR performance of an output signal can far meet the protocol requirement, but the working current of the power amplifier is large, and the efficiency is low; if the value is too small, the load impedance of the power amplifier can be increased, and the current consumed by the power amplifier can be reduced, but if the gain compression occurs too early, part of signals with higher average power can be distorted, and the ACLR performance can not meet the protocol requirements.

There are many methods for reducing the influence of gain compression of a power amplifier on the ACLR performance of an output signal while considering efficiency, such as digital compensation methods of envelope tracking, digital predistortion, etc., which have good effects, but require external chip cooperation, and are high in cost and complex in control. The other method is that an AM-AM compensating circuit is added at the front end of the power amplifier, and under the condition that the amplitude of an input signal of the power amplifier is increased, the gain compression caused by AM-AM distortion is compensated by increasing the bias current (voltage) of the power amplifier.

A compensation circuit based on diode detection is shown in figure 1, a bias circuit consisting of an N-Metal-Oxide-Semiconductor (NMOS) tube M1, a filter capacitor C1, an isolation resistor R1 and a current source Ib is added with an NMOS tube D1, the grid and the drain of the D1 are in short circuit and used as a diode to separate a node voltage Vg from a node voltage Vd, and the detection effect of D1 can lift the Vin voltage when a large signal is input so as to compensate the gain compression of an amplifier M2 under the large signal.

The principle of the compensation circuit shown in fig. 1 is as follows: under the condition of quiescent current, because D1 has leakage, the time is long enough, and finally Vg is Vd Vin is Vin 0; when the power amplifier works, when the amplitude of the radio frequency signal is negative, the reverse amplitude of oscillation of Vin exceeds the threshold voltage Vth of D1, D1 is conducted, the voltage of Vin is clamped to Vin0-Vth, so that Vin can not swing downwards any more, and when the amplitude of the radio frequency signal is positive, the forward amplitude of oscillation of Vin is not limited by D1. After a few rf cycles are stable, the positive swing of Vin is higher than the negative swing, as shown in fig. 2. From the Fourier analysis, the Vin waveform DC component will be higher than the initial Vin, and the Vin voltage will rise to Vin 1. When the input signal power Pin is larger, the Vin voltage swing is larger, the detection effect of the diode D1 is more obvious, the VinDC level is higher, as shown in fig. 3, and the gain compression compensation effect is as shown in fig. 4.

The compensation circuit shown in fig. 1 has a serious problem that the quiescent current is set up for too long; as can be seen from circuit analysis, the set-up time of Vin depends on the RC constant (constant of the time course of the transient reaction) of the node, where the node resistance Rnet ═ (cut-off equivalent resistance Requ + isolation resistance R1 of D1), and the cut-off equivalent resistance Requ of D1 is usually very large, about 0.5x10⁹ohm, the node capacitance Cnet1 ≈ 4pF (equivalent Cgate + filter capacitance C1 of gate capacitance of power tube M2), the time constant is about 2ms, the settling time is about 8ms and the shift is performed by estimating 4 times of the time constantThe rising edge establishment time of the power amplifier is required to be less than or equal to 10us in the dynamic communication protocol, and the circuit is far from meeting the protocol requirement and cannot be directly used in the radio frequency power amplifier. Therefore, the following technical scheme of the embodiment of the application is provided.

Fig. 5 is a schematic structural diagram of a compensation circuit for amplitude modulation to amplitude modulation of the rf power amplifier according to an embodiment of the present application. As shown in fig. 5, the amplitude modulation-to-amplitude modulation compensation circuit of the radio frequency power amplifier includes: a first bias circuit 51, a power amplifier 52, and a compensation circuit 53 between the first bias circuit 51 and the power amplifier 52; wherein the content of the first and second substances,

the compensation circuit 53 includes a diode detector circuit 531 and a feed forward amplifier 532 for compensating for the AM-AM distortion.

In the technical solution of this embodiment, a compensation circuit including a diode detector circuit and a feed-forward amplifier is provided between the first bias circuit and the power amplifier, and the diode detector circuit in the compensation circuit can compensate gain compression due to AM-AM distortion by increasing the bias current (voltage) of the power amplifier when the amplitude of the input signal to the power amplifier becomes large. On the other hand, the requirement of the mobile communication protocol on the set-up time of the power amplifier can be met by the feed-forward amplifier in the compensation circuit.

It should be noted that the compensation circuit in the embodiment of the present application may also be referred to as an AM-AM compensation circuit because it can compensate for gain compression occurring due to AM-AM distortion.

The following describes an amplitude modulation and amplitude modulation compensation circuit of a radio frequency power amplifier according to an embodiment of the present invention with reference to a specific circuit structure, where it should be noted that the following embodiments are merely illustrative and do not limit the scope of the embodiments of the present invention.

Fig. 6 is a first circuit schematic diagram of a circuit for compensating amplitude modulation versus amplitude modulation of a radio frequency power amplifier according to an embodiment of the present application, and as shown in fig. 6, the circuit for compensating amplitude modulation versus amplitude modulation of a radio frequency power amplifier includes: a first bias circuit 61, a power amplifier 62, and a compensation circuit 63 between the first bias circuit 61 and the power amplifier 62; wherein the content of the first and second substances,

the compensation circuit 63 includes a diode detector circuit and a feed forward amplifier for compensating for AM-AM distortion.

In an alternative embodiment, the diode detector circuit in the compensation circuit 63 includes: a first transistor D1, and a first resistor R2 connected in parallel with the first transistor D1; wherein the gate and the drain of the first transistor D1 are shorted and are both connected to the first bias circuit 61; the source of the first transistor D1 is connected to a first terminal of the power amplifier 62, and the first terminal of the power amplifier 62 is the gate of a second transistor M2 in the power amplifier 62.

In an alternative embodiment, the feed forward amplifier in the compensation circuit 63 comprises: a first capacitor Cb2, a third transistor M3, and a second capacitor Cb 3; a first end of the first capacitor Cb2 is connected to the radio frequency input terminal RFin, and a second end of the first capacitor Cb2 is connected to the gate of the third transistor M3; the source of the third transistor M3 is connected to ground, the drain of the third transistor M3 is connected to the first end of the second capacitor Cb3, and the second end of the second capacitor Cb3 is connected to the drain of the first transistor D1.

In an alternative embodiment, the feed forward amplifier in the compensation circuit 63 further comprises a second bias circuit for providing a bias current to the third transistor M3; wherein the second bias circuit is connected to the gate of the third transistor M3.

In an alternative embodiment, the feed forward amplifier 63 further comprises a voltage source VCC1, and a second resistor R3 connected in series with the voltage source VCC1 for providing a drain bias voltage for the third transistor M3; the second resistor R3 is connected to the drain of the third transistor M3.

In an alternative embodiment, the first bias circuit includes a first current source Ib1, a fourth transistor M1, a third capacitor C1, and a third resistor R1.

In an alternative embodiment, the second bias circuit includes a second current source Ib2, a fifth transistor M4, a fourth capacitor C2, and a fourth resistor R4.

In an alternative embodiment, the power amplifier includes a second transistor M2, a fifth capacitor Cb1, and a sixth capacitor Cb 2.

Based on the circuit structure, the compensation circuit is composed of the following two parts:

first part (diode detector circuit): in specific implementation, a diode detection circuit is formed by a diode-connected NMOS tube D1 (namely, a first transistor D1) and a parallel isolation resistor R2 (namely, a first resistor R2), wherein the equivalent direct-current resistance of D1 can be effectively reduced by the resistor R2, the total resistance of a node of a bias circuit is reduced, and the static current establishment time can be remarkably improved.

Second part (feed forward amplifier): in a specific implementation, the dc blocking capacitor Cb2 (i.e., the first capacitor Cb2), the NMOS amplifier tube M3 (i.e., the third transistor M3) and the feedforward capacitor Cb3 (i.e., the third transistor M3) form a feedforward amplifier. Further, the bias current of the feed-forward amplifier is provided by a second bias circuit composed of a current source Ib2 (i.e., a second current source Ib2), an NMOS transistor M4 (i.e., a fifth transistor M4), a filter capacitor C2 (i.e., a fourth capacitor C2) and a radio frequency isolation resistor R4 (i.e., a fourth resistor R4); the drain bias voltage of the feed forward amplifier is provided by a voltage source VCC1 and a bias resistor R3 (i.e., a second resistor R3); the feed-forward amplifier can effectively enhance the detection effect of D1 and effectively compensate the influence introduced by the isolation resistor R2.

The working principle of the compensating circuit for amplitude modulation of the radio frequency power amplifier is as follows:

when the rf voltage swing of the rf input terminal RFin is positive and the amplitude is Vp, a part of the rf voltage is fed to the gate of M3 in the feed-forward amplifier through the separation capacitor Cb2, and the feed-forward amplifier is a common-source amplifier, the rf voltage swing of the drain of M3 is reversed to negative, after passing through the feed-forward capacitor Cb3, the rf voltage swing of the node Vd is still negative, the swing of the gate rf voltage Vin of M2 is still positive, the gate voltage of the NMOS transistor D1 is lower than the source voltage by Vp, R1 (i.e., the third resistor R1) is generally 20kohm, the Vd rf signal is isolated from the Vg voltage, the isolation resistor R2 is generally about 5kohm and is much smaller than the equivalent resistor of D1, the Vin forward voltage swing is affected by the charge leakage of the paths of R2 and Cb3, and the upper limit of the swing is limited.

When the radio-frequency voltage swing of the radio-frequency input end RFin is negative, the amplitude is Vp, a part of radio-frequency voltage is fed into the grid electrode of M3 in the feed-forward amplifier through the isolating capacitor Cb2, the radio-frequency voltage swing of the drain electrode of M3 is reversed to be positive, after passing through the feed-forward capacitor Cb3, the radio-frequency voltage swing of the node Vd is positive, the swing of the grid-frequency voltage Vin of M2 is still negative, the grid-frequency voltage of the NMOS tube D1 is higher than Vp than the source-frequency voltage, D1 is conducted, Vin is clamped to (Vp + Vin0) -Vth and is higher than Vin0-Vth of the existing circuit, and the lower limit of the; proper circuit parameters are selected, so that the forward-feed amplifier is stronger in the increase of negative swing of Vin through D1 than the limitation of charge discharge of the paths of R2, R1 and the bias tube M1 on the positive swing of Vin, the purpose of raising the grid direct-current voltage of the amplifying tube M2 is achieved, and the effect of compensating large signal gain is achieved. The quiescent current settling time of the circuit depends on the node time constant RC.

Wherein node resistance Rnet2 is isolation resistance R1+ R2 is 25 kohm;

the node capacitance Cnet2 is C1+ Cb3+ Cb1+ Cgate ≈ 2pF +2pF +4pF +2pF ═ 10pF, the time constant is about 250ns, the time constant is estimated according to 4 times, the establishment time is about 1us, and the requirement of the protocol on the establishment time of the power amplifier is met.

According to the technical scheme of the embodiment of the application, the compensation circuit comprising the diode detection circuit and the feed-forward amplifier is arranged between the first bias circuit and the power amplifier, and the diode detection circuit in the compensation circuit can compensate gain compression caused by AM-AM distortion by improving the bias current (voltage) of the power amplifier under the condition that the amplitude of an input signal of the power amplifier is increased. On the other hand, the requirement of the mobile communication protocol on the set-up time of the power amplifier can be met by the feed-forward amplifier in the compensation circuit. The radio frequency power amplifier amplitude modulation of the embodiment of the application is relatively simple to realize the amplitude modulation compensation circuit, flexible in design, good in applicability, easy to integrate and low in cost, and AMAM programming can be adjusted by adjusting parameters in the compensation circuit.

Optionally, in fig. 6, the first resistor R2 in the diode detector circuit is a variable resistor, so as to form a circuit structure as shown in fig. 7, and by changing the resistance of R2, the programmable control of the power point and the compensation amplitude of the AM-AM compensation turn-on is realized, thereby achieving the purpose of increasing the applicability and flexibility of the circuit.

Optionally, in fig. 6, the amplification factor of the feed forward amplifier in the compensation circuit of amplitude modulation to amplitude modulation of the radio frequency power amplifier is an adjustable amplification factor, wherein the parameter of the third transistor M3 in the feed forward amplifier is adjustable; and/or the current parameter of the first current source Ib2 in the second bias circuit in the feed-forward amplifier is adjustable, so that the circuit structure shown in FIG. 8 is formed, and the power point and the compensation amplitude programming control of the starting of the AM-AM compensation are realized by changing the amplification factor method of the feed-forward amplifier.

Optionally, in fig. 6, the compensation circuit of the compensation circuit for amplitude modulation to amplitude modulation of the radio frequency power amplifier further includes a circuit switch S1, two terminals of the circuit switch S1 are connected in parallel with two terminals of the first transistor D1, so as to form a circuit structure as shown in fig. 9, and whether to enable the compensation circuit can be selected through the switch S1, S1 is opened, the compensation circuit is activated, S1 is closed, and the compensation circuit is deactivated.

Optionally, in fig. 6, the power amplifier of the rf power amplifier amplitude modulation vs. amplitude modulation compensation circuit includes a second transistor M2; or, the number of the second transistors M2 is expanded, the power amplifier includes a plurality of second transistors M2, and a stacked-tube structure is formed between the plurality of second transistors, so as to form a circuit structure as shown in fig. 10, wherein the number of the second transistors M2 is n, n is an integer greater than or equal to 2, n M2 shown in fig. 10 includes M21, M22, … …, M2n, and a stacked-tube structure is formed between the n M2.

It should be noted that the type of the Transistor in the embodiment of the present application is not limited to an NMOS Transistor, and may be other types of power transistors, such as a Heterojunction Bipolar Transistor (HBT) Bipolar Junction Transistor (BJT).

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application.