阅读说明：本技术 一种功率管模拟电路、输出级电路及功率放大器 (Power tube analog circuit, output stage circuit and power amplifier ) 是由 樊小明 于 2019-09-23 设计创作，主要内容包括：本发明提供了一种功率管模拟电路、输出级电路及功率放大器,其中所述功率管模拟电路包括信号传输电路和功率管；所述信号传输电路的第一端与所述功率管的第一端之间的共接点作为所述功率管模拟电路的第一端,所述信号传输电路的第二端作为功率管模拟电路的第二端；所述信号传输电路的第三端与所述功率管的第二端连接,所述信号传输电路的第四端与所述功率管的第三端之间的共接点作为所述功率管模拟电路的第三端。通过所述信号传输电路可以将功率管模拟成与之互补的具有大功率的另一功率管,从而解决了对称高压大功率的输出级电路的构建困难,有效地提高了现有功率放大器的输出级电路的耐压程度和输出功率。(The invention provides a power tube analog circuit, an output stage circuit and a power amplifier, wherein the power tube analog circuit comprises a signal transmission circuit and a power tube; a common joint between the first end of the signal transmission circuit and the first end of the power tube is used as the first end of the power tube analog circuit, and the second end of the signal transmission circuit is used as the second end of the power tube analog circuit; and a common joint between the fourth end of the signal transmission circuit and the third end of the power tube is used as the third end of the power tube analog circuit. The signal transmission circuit can simulate the power tube into another power tube which is complementary with the power tube and has high power, thereby solving the problem of difficult construction of a symmetrical high-voltage high-power output stage circuit and effectively improving the withstand voltage degree and the output power of the output stage circuit of the traditional power amplifier.)

1. A power tube simulation circuit is characterized by comprising a signal transmission circuit and a power tube;

a common joint between the first end of the signal transmission circuit and the first end of the power tube is used as the first end of the power tube analog circuit, and the second end of the signal transmission circuit is used as the second end of the power tube analog circuit; the third end of the signal transmission circuit is connected with the second end of the power tube, and a common joint between the fourth end of the signal transmission circuit and the third end of the power tube is used as the third end of the power tube analog circuit;

the ratio of an input signal between the first end and the second end of the signal transmission circuit to an output signal between the third end and the fourth end of the signal transmission circuit is a proportionality coefficient K, wherein the proportionality coefficient K is a positive integer;

when a voltage signal/current signal exists between the first end and the second end of the power tube analog circuit, the signal transmission circuit acquires the voltage signal/current signal between the first end and the second end of the power tube analog circuit as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between the second end and the third end of the power tube so as to conduct the power tube.

2. The power tube simulation circuit according to claim 1, wherein the signal transmission circuit is an isolated signal transmission circuit or a non-isolated signal transmission circuit.

3. The power tube simulation circuit according to claim 2, wherein when the signal transmission circuit is an isolated signal transmission circuit, the signal transmission circuit comprises a photoelectric isolation module;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the photoelectric isolation module, and the photoelectric isolation module converts the input signal into an output signal according to a photoelectric isolation principle and transmits the output signal to a position between a second end and a third end of the power tube so as to enable the power tube to be conducted; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

4. The power tube simulation circuit according to claim 3, wherein the optoelectronic isolation module comprises: the LED comprises a first resistor, a light emitting diode, a photodiode, an operational amplifier and a second resistor;

a common joint between one end of the first resistor and the first end of the power tube is used as the first end of the power tube analog circuit, the other end of the first resistor is connected with the anode of the light-emitting diode, and the cathode of the light-emitting diode is used as the second end of the power tube analog circuit and is connected with the floating ground for output;

a common junction point between the anode of the photodiode and the third end of the power tube is used as the third end of the power tube analog circuit, the cathode of the photodiode and one end of the second resistor are connected to the inverting input end of the operational amplifier in common, the non-inverting input end of the operational amplifier is grounded, and a common junction point between the other end of the second resistor and the output end of the operational amplifier is connected to the second end of the power tube;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the photoelectric isolation module, and acts on a light emitting diode through a first resistor to enable the light emitting diode to be conducted to generate an optical signal, the light emitting diode receives the optical signal, converts the optical signal into an electrical signal and transmits the electrical signal to an operational amplifier, and the operational amplifier scales the electrical signal according to a scaling coefficient K to obtain an output signal of the photoelectric isolation module; the output signal is transmitted between the second end and the third end of the power tube so as to conduct the power tube; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

5. The power tube simulation circuit according to claim 3, wherein the optoelectronic isolation module comprises: the circuit comprises a first resistor, a first operational amplifier, a second resistor, a linear optocoupler module, a second operational amplifier and a third resistor;

a common junction point between one end of the first resistor and the first end of the power tube is used as a first end of the power tube analog circuit, a common junction point between the other end of the first resistor and the third end of the linear optocoupler module is connected with an inverting input end of the first operational amplifier, and a positive phase input end of the first operational amplifier is used as a second end of the power tube analog circuit and connected with a floating ground for output; the output end of the first operational amplifier is connected with one end of the second resistor, the other end of the second resistor is connected with the first end of the linear optical coupling module, the second end of the linear optical coupling module is connected with a power supply, and the fourth end of the linear optical coupling module is connected with a floating ground output; a common joint between a fifth end of the linear optocoupler module and a positive phase input end of the second operational amplifier and a third end of the power tube is grounded and is used as a third end of the power tube analog circuit; a sixth end of the linear optocoupler module and one end of the third resistor are connected to the inverting input end of the second operational amplifier in a shared mode, and a shared joint between the other end of the third resistor and the output end of the second operational amplifier is connected with the second end of the power tube;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the photoelectric isolation module, the input signal is amplified by a first operational amplifier and then acts on the linear optical coupling module, the linear optical coupling module generates an optical signal, the optical signal is converted into an electric signal and is transmitted to a second operational amplifier and fed back to the first operational amplifier, and the second operational amplifier scales the electric signal according to a proportionality coefficient K to obtain an output signal of the photoelectric isolation module; the output signal is transmitted between the second end and the third end of the power tube so as to conduct the power tube; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

6. The power tube simulation circuit according to claim 2, wherein when the signal transmission circuit is an isolated signal transmission circuit, the signal transmission circuit comprises a magnetic isolation module;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the magnetic isolation module, the magnetic isolation module converts the input signal into an output signal according to an electromagnetic isolation principle and transmits the output signal to a position between a second end and a third end of the power tube so as to enable the power tube to be conducted; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

7. The power tube analog circuit of claim 6, wherein the magnetic isolation module comprises: a capacitor, a transformer;

a common junction point between a first end of the primary winding of the transformer and a first end of the power tube is used as a first end of the power tube analog circuit, a second end of the primary winding of the transformer is connected with the capacitor, and the other end of the capacitor is used as a second end of the power tube analog circuit; a first end of a secondary winding in the transformer is connected with a second end of the power tube, and a common joint between the second end of the secondary winding and a third end of the power tube is used as a third end of the power tube analog circuit; the first end of the primary winding and the first end of the secondary winding are homonymous ends, and the second end of the primary winding and the second end of the secondary winding are homonymous ends;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the magnetic isolation module and acts on a primary winding of a transformer, a secondary winding of the transformer induces an electric signal according to the proportionality coefficient K, and the electric signal is used as an output signal of the magnetic isolation module and transmitted between a second end and a third end of the power tube so as to conduct the power tube; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

8. The power tube simulation circuit according to claim 2, wherein when the signal transmission circuit is an isolated signal transmission circuit, the signal transmission circuit comprises a capacitive isolation module;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit is used as an input signal of the capacitive isolation module, the capacitive isolation module converts the input signal into an output signal according to a capacitive coupling principle and transmits the output signal to a position between a second end and a third end of the power tube so as to enable the power tube to be conducted; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

9. The power tube simulation circuit according to claim 2, wherein when the signal transmission circuit is a non-isolated signal transmission circuit, the signal transmission circuit comprises a differential operational amplifier circuit;

a common junction point between a first signal input end of the differential operational amplification circuit and a first end of the power tube is used as a first end of the power tube analog circuit, and a second signal input end of the differential operational amplification circuit is used as a second end of the power tube analog circuit; the output end of the differential operational amplification circuit is connected with the second end of the power tube, and the common joint between the third input end of the differential operational amplification circuit and the third end of the power tube is connected with the floating ground for output as the third end of the power tube analog circuit;

in the signal transmission circuit, the differential operational amplification circuit obtains a voltage signal/current signal of a first end of the power tube analog circuit through a first signal input end, obtains a voltage signal/current signal of a second end of the power tube analog circuit through a second signal input end to obtain an input signal, and then converts the input signal into an output signal according to a proportionality coefficient K to transmit the output signal between the second end and a third end of the power tube so as to conduct the power tube; when the power tube is conducted, the power tube simulation circuit forms a complementary power tube of the power tube.

10. The power transistor analog circuit according to any one of claims 1 to 9, wherein when the power transistor is an N-channel MOS transistor, a common junction between the first terminal of the signal transmission circuit and the drain of the N-channel MOS transistor serves as a source of the power transistor analog circuit, and the second terminal of the signal transmission circuit serves as a gate of the power transistor analog circuit; the third end of the signal transmission circuit is connected with the grid electrode of the N-channel MOS transistor, and a common joint between the fourth end of the signal transmission circuit and the source electrode of the N-channel MOS transistor is used as the drain electrode of the power tube analog circuit;

when a voltage signal exists between the source electrode and the grid electrode of the power tube analog circuit, the signal transmission circuit acquires the voltage signal between the source electrode and the grid electrode of the power tube analog circuit as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between the grid electrode and the source electrode of the N-channel MOS transistor so as to enable the N-channel MOS transistor to be conducted; when the N-channel MOS transistor is conducted, the power tube simulation circuit forms a P-channel MOS transistor which is complementary with the N-channel MOS transistor.

11. The power transistor analog circuit according to any one of claims 1 to 9, wherein when the power transistor is an NPN transistor, a common junction between the first terminal of the signal transmission circuit and the collector of the NPN transistor serves as an emitter of the power transistor analog circuit, and the second terminal of the signal transmission circuit serves as a base of the power transistor analog circuit; the third end of the signal transmission circuit is connected with the base electrode of the NPN type triode, and a common contact between the fourth end of the signal transmission circuit and the emitting electrode of the NPN type triode is used as a collector electrode of the power tube analog circuit;

when a current signal exists between the emitter and the base of the power tube analog circuit, the signal transmission circuit acquires the current signal between the emitter and the base of the power tube analog circuit as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between the base and the emitter of the NPN type triode so as to conduct the NPN type triode; when the NPN type triode is conducted, the power tube simulation circuit forms a PNP type triode which is complementary with the NPN type triode.

12. An output stage circuit of a power amplifier, the output stage circuit comprising: an N-channel MOS transistor and the power transistor analog circuit of claim 10;

a common joint between the grid of the N-channel MOS transistor and the grid of the power tube analog circuit is used as the input end of the output stage circuit and is connected with the output end of the voltage amplification stage of the power amplifier;

a common joint between the source electrode of the N-channel MOS transistor and the source electrode of the power tube analog circuit is used as the output end of the output stage circuit and is connected with a load;

the drain electrode of the N-channel MOS transistor is connected with the positive electrode of a power supply, and the drain electrode of the power tube analog circuit is connected with the negative electrode of the power supply.

13. An output stage circuit of a power amplifier, the output stage circuit comprising: an NPN type transistor and a power transistor analog circuit as claimed in claim 11;

a common junction point between the base electrode of the NPN type triode and the base electrode of the power tube analog circuit is used as the input end of the output stage circuit and is connected with the output end of the voltage amplification stage of the power amplifier;

a common joint between the emitter of the NPN type triode and the emitter of the power tube analog circuit is used as the output end of the output stage circuit and is connected with a load;

and the collector of the NPN type triode is connected with the anode of the power supply, and the collector of the power tube analog circuit is connected with the cathode of the power supply.

14. A power amplifier, characterized in that the power amplifier comprises: an N-channel MOS transistor, the power tube analog circuit of claim 10, a third operational amplifier, a fourth resistor, a fifth resistor;

a positive phase input end of the third operational amplifier is connected with an input voltage, an inverted phase input end of the third operational amplifier is connected with the fifth resistor, and the other end of the fifth resistor is connected with a floating ground output;

the output end of the third operational amplifier is respectively connected with the grid electrode of the N-channel MOS transistor and the grid electrode of the power tube analog circuit;

a common junction point between the source electrode of the N-channel MOS transistor and the source electrode of the power tube analog circuit is connected with a load and the fourth resistor, and the other end of the fourth resistor is connected with the reverse input end of the third operational amplifier;

the drain electrode of the N-channel MOS transistor is connected with the positive electrode of a power supply, and the drain electrode of the power tube analog circuit is connected with the negative electrode of the power supply.

15. A power amplifier, characterized in that the power amplifier comprises: an NPN type triode, a power tube analog circuit as claimed in claim 11, a third operational amplifier, a fourth resistor and a fifth resistor;

a positive phase input end of the third operational amplifier is connected with an input voltage, an inverted phase input end of the third operational amplifier is connected with the fifth resistor, and the other end of the fifth resistor is connected with a floating ground output;

the output end of the third operational amplifier is respectively connected with the base electrode of the NPN type triode and the base electrode of the power tube analog circuit;

a common junction point between the emitting electrode of the NPN type triode and the emitting electrode of the power tube analog circuit is connected with a load and the fourth resistor, and the other end of the fourth resistor is connected with the reverse input end of the third operational amplifier;

and the collector of the NPN type triode is connected with the anode of the power supply, and the collector of the power tube analog circuit is connected with the cathode of the power supply.

Technical Field

The invention relates to the technical field of overcurrent protection, in particular to a power tube analog circuit, an output stage circuit and a power amplifier.

Background

A linear power amplifier is an amplifier that amplifies voltage and current of a small signal to drive a large power load, and is widely used in various fields of electronic technology, such as speakers and motors. The power amplifier is composed of a preceding stage amplifying circuit, a driving stage circuit and an output stage circuit. The pre-stage amplifying circuit and the pushing stage circuit are voltage amplifiers, only the voltage of a signal is amplified, and the current of the circuits is very small, so that the heating and the loss are not large, and the circuit is not easy to damage. The power output stage circuit is an emitter follower or a source follower, the output end is directly connected with a load, and the voltage amplification factor is 1.

In the prior art, the output stage circuit of the power amplifier usually consists of a pair of complementary bipolar transistors BJT to form an emitter follower, such as an NPN-type transistor and a PNP-type transistor; or a source follower is formed by a pair of complementary field effect transistors, MOSFETs, such as an N-channel MOS transistor and a P-channel MOS transistor. The high-power NPN triode and the N-channel MOS transistor are very common components and are easily purchased in the market. However, the varieties of the high-power PNP transistor and the P-channel MOS transistor are very few, and the high-power PNP transistor and the P-channel MOS transistor with high power or high withstand voltage are not manufactured by manufacturers. Therefore, it is very difficult to construct a symmetrical high-voltage high-power output stage circuit. In the prior art, a PNP-type triode and an N-channel MOS transistor are compounded into a P-channel-like MOS transistor, however, the compound transistor is limited by the performance of the PNP-type triode, the withstand voltage degree of an output stage circuit of the power amplifier is not high, the input resistance is not large, and the output power of the output stage circuit is limited.

Disclosure of Invention

The invention provides a power tube analog circuit, an output stage circuit and a power amplifier, which aim to solve the problems that the construction of a symmetrical high-voltage high-power output stage circuit is difficult, the voltage withstanding degree of the output stage circuit is not high, and the output power is not high.

The invention is realized in such a way that the power tube simulation circuit comprises a signal transmission circuit and a power tube;

a common joint between the first end of the signal transmission circuit and the first end of the power tube is used as the first end of the power tube analog circuit, and the second end of the signal transmission circuit is used as the second end of the power tube analog circuit; the third end of the signal transmission circuit is connected with the second end of the power tube, and a common joint between the fourth end of the signal transmission circuit and the third end of the power tube is used as the third end of the power tube analog circuit;

the ratio of an input signal between the first end and the second end of the signal transmission circuit to an output signal between the third end and the fourth end of the signal transmission circuit is a proportionality coefficient K, wherein the proportionality coefficient K is a positive integer;

when a voltage signal/current signal exists between the first end and the second end of the power tube analog circuit, the signal transmission circuit acquires the voltage signal/current signal between the first end and the second end of the power tube analog circuit as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between the second end and the third end of the power tube so as to conduct the power tube.

In a second aspect, an output stage circuit of a power amplifier is provided, the output stage circuit comprising: an N-channel MOS transistor and the power tube analog circuit;

a common joint between the grid of the N-channel MOS transistor and the grid of the power tube analog circuit is used as the input end of the output stage circuit and is connected with the output end of the voltage amplification stage of the power amplifier;

a common joint between the source electrode of the N-channel MOS transistor and the source electrode of the power tube analog circuit is used as the output end of the output stage circuit and is connected with a load;

the drain electrode of the N-channel MOS transistor is connected with the positive electrode of a power supply, and the drain electrode of the power tube analog circuit is connected with the negative electrode of the power supply.

In a third aspect, an output stage circuit of a power amplifier is provided, the output stage circuit comprising: the NPN type triode and the power tube analog circuit are arranged;

a common junction point between the base electrode of the NPN type triode and the base electrode of the power tube analog circuit is used as the input end of the output stage circuit and is connected with the output end of the voltage amplification stage of the power amplifier;

a common joint between the emitter of the NPN type triode and the emitter of the power tube analog circuit is used as the output end of the output stage circuit and is connected with a load;

and the collector of the NPN type triode is connected with the anode of the power supply, and the collector of the power tube analog circuit is connected with the cathode of the power supply.

In a fourth aspect, a power amplifier is provided, the power amplifier comprising: the power transistor comprises an N-channel MOS transistor, the power transistor analog circuit, a third operational amplifier, a fourth resistor and a fifth resistor;

a positive phase input end of the third operational amplifier is connected with an input voltage, an inverted phase input end of the third operational amplifier is connected with the fifth resistor, and the other end of the fifth resistor is connected with a floating ground output;

the output end of the third operational amplifier is respectively connected with the grid electrode of the N-channel MOS transistor and the grid electrode of the power tube analog circuit;

a common junction point between the source electrode of the N-channel MOS transistor and the source electrode of the power tube analog circuit is connected with a load and the fourth resistor, and the other end of the fourth resistor is connected with the reverse input end of the third operational amplifier;

the drain electrode of the N-channel MOS transistor is connected with the positive electrode of a power supply, and the drain electrode of the power tube analog circuit is connected with the negative electrode of the power supply.

In a fifth aspect, a power amplifier is provided, the power amplifier comprising: the NPN type triode, the power tube analog circuit, the third operational amplifier, the fourth resistor and the fifth resistor are arranged in the power tube analog circuit;

a positive phase input end of the third operational amplifier is connected with an input voltage, an inverted phase input end of the third operational amplifier is connected with the fifth resistor, and the other end of the fifth resistor is connected with a floating ground output;

the output end of the third operational amplifier is respectively connected with the base electrode of the NPN type triode and the base electrode of the power tube analog circuit;

a common junction point between the emitting electrode of the NPN type triode and the emitting electrode of the power tube analog circuit is connected with a load and the fourth resistor, and the other end of the fourth resistor is connected with the reverse input end of the third operational amplifier;

and the collector of the NPN type triode is connected with the anode of the power supply, and the collector of the power tube analog circuit is connected with the cathode of the power supply.

The power tube simulation circuit provided by the invention comprises a power tube and a signal transmission circuit, wherein the power tube can be simulated into a complementary power tube with high power through the signal transmission circuit, and the power tube simulation circuit is applied to an output stage of a power amplifier, so that the difficulty in constructing a symmetrical high-voltage high-power output stage circuit can be solved, and the voltage withstanding degree and the output power of the output stage circuit of the conventional power amplifier are effectively improved.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a power transistor analog circuit according to an embodiment of the present invention;

fig. 2 is a circuit diagram of a power tube simulation circuit according to an embodiment of the present invention;

fig. 3 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 4 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 5 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 6 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 7 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 8 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 9 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

fig. 10 is a circuit diagram of a power tube simulation circuit according to another embodiment of the present invention;

FIG. 11 is a schematic diagram of an output stage according to an embodiment of the present invention;

FIG. 12 is a schematic diagram of an output stage according to another embodiment of the present invention;

fig. 13 is a schematic structural diagram of a power amplifier according to an embodiment of the present invention;

fig. 14 is a schematic structural diagram of a power amplifier according to another embodiment of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The invention provides a power tube simulation circuit which is used for simulating a power tube into another power tube complementary to the power tube. Fig. 1 shows a schematic structural diagram of a power tube analog circuit according to an embodiment of the present invention. As shown in fig. 1, the power tube simulation circuit 10 includes: a signal transmission circuit 11 and a power tube 12.

A common junction point between the first end of the signal transmission circuit 11 and the first end of the power tube 12 is used as a first end of the power tube analog circuit 10, and the second end of the signal transmission circuit 11 is used as a second end of the power tube analog circuit 10; the third end of the signal transmission circuit 11 is connected with the second end of the power tube 12, and a common junction point between the fourth end of the signal transmission circuit 11 and the third end of the power tube 12 is used as the third end of the power tube analog circuit 10;

the ratio of an input signal between the first end and the second end of the signal transmission circuit 11 to an output signal between the third end and the fourth end of the signal transmission circuit 11 is a proportionality coefficient K, wherein the proportionality coefficient K is a positive integer;

when a voltage signal/current signal exists between the first end and the second end of the power tube analog circuit 10, the signal transmission circuit 11 obtains the voltage signal/current signal between the first end and the second end of the power tube analog circuit 10 as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between the second end and the third end of the power tube 12 to conduct the power tube 12, and when the power tube 12 is conducted, the power tube analog circuit 10 forms a complementary power tube of the power tube 12.

In this embodiment, the signal transmission circuit 11 takes the voltage signal/current signal between the first terminal and the second terminal of the power transistor analog circuit 10 as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and applies the output signal between the second terminal and the third terminal of the power transistor 12 to turn on the power transistor 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12. The power tube analog circuit 10 and the power tube 12 are commonly applied to the output stage of the power amplifier, so that the withstand voltage degree and the output power of the output stage circuit of the existing power amplifier can be effectively improved. In order to solve the difficulty in constructing a symmetrical high-voltage high-power output stage circuit, the power tube 12 may be a power tube which is commonly available on the market and is easily purchased.

Optionally, the signal transmission circuit includes, but is not limited to, an isolated signal transmission circuit, a non-isolated signal transmission circuit. The isolated signal transmission circuit realizes the transmission and conversion of signals in an isolated mode, and the non-isolated signal transmission circuit realizes the transmission and conversion of signals in a non-isolated mode.

Specifically, as an embodiment, as shown in fig. 2, when the signal transmission circuit 11 is an isolated signal transmission circuit, the signal transmission circuit 11 includes a photoelectric isolation module 111;

in the signal transmission circuit, a voltage signal/current signal between a first terminal and a second terminal of the power tube analog circuit 10 is used as an input signal of the optoelectronic isolation module 111, and the optoelectronic isolation module 111 converts the input signal into an output signal according to an optoelectronic isolation principle and transmits the output signal to a place between a second terminal and a third terminal of the power tube 12, so that the power tube 12 is turned on; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In this embodiment, the optoelectronic isolation module 111 includes an optical coupling portion and an optical isolation portion. The voltage signal/current signal between the first terminal and the second terminal of the power tube analog circuit 10 is applied to the optical coupling portion of the optoelectronic isolation module 111 as the input signal of the optoelectronic isolation module 111. When the optical coupling part generates an optical signal according to an input signal, the optical coupling part receives the optical signal and generates a photocurrent, and outputs an electrical signal according to the scaling factor K as an output signal of the optoelectronic isolation module 111. The output signal is applied between the second terminal and the third terminal of the power tube 12 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

Optionally, the optoelectronic isolation module 111 may adopt a packaged optoelectronic isolation module, such as an optoelectronic isolation module with a model number of AD203, or AD204, or may adopt a customized optoelectronic isolation module.

Specifically, as an embodiment, as shown in fig. 3, the optoelectronic isolation module 111 includes: the LED driving circuit comprises a first resistor R1, a light emitting diode LED, a photodiode PD1, an operational amplifier U1 and a second resistor R2;

a common junction point between one end of the first resistor R1 and the first end of the power tube 12 is used as a first end of the power tube analog circuit 10, the other end of the first resistor R1 is connected with an anode of the light emitting diode LED, and a cathode of the light emitting diode LED is used as a second end of the power tube analog circuit 10 and is output in a floating manner;

a common junction point between the anode of the photodiode PD1 and the third terminal of the power transistor 12 is used as the third terminal of the power transistor analog circuit 10, the cathode of the photodiode PD1 and one end of the second resistor R2 are connected to the inverting input terminal of the operational amplifier U1 in common, the non-inverting input terminal of the operational amplifier U1 is grounded, and a common junction point between the other end of the second resistor R2 and the output terminal of the operational amplifier U1 is connected to the second terminal of the power transistor 12;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit 10 is used as an input signal of the optoelectronic isolation module 111, and is applied to a light emitting diode LED through a first resistor R1, so that the light emitting diode LED is turned on to generate an optical signal, the photodiode PD1 receives and converts the optical signal into an electrical signal to be transmitted to an operational amplifier U1, and the operational amplifier U1 scales the electrical signal according to a scaling coefficient K to obtain an output signal of the optoelectronic isolation module 111. The output signal is transmitted between the second end and the third end of the power tube 12 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In the present embodiment, the first resistor R1 and the light emitting diode LED constitute an optical coupling portion of the optoelectronic isolation module 111, and the photodiode PD1, the operational amplifier U1 and the second resistor R2 constitute an optical isolation portion of the optoelectronic isolation module 111. The voltage signal/current signal between the first terminal and the second terminal of the power tube analog circuit 10 is applied to the optical coupling portion of the optoelectronic isolation module 111 as the input signal of the optoelectronic isolation module 111. When the input signal is applied to the light emitting diode LED through the first resistor R1, the light emitting diode LED is turned on to generate an optical signal, the photodiode PD1 receives and converts the optical signal into an electrical signal to be transmitted to the operational amplifier U1, and the electrical signal is converted into an output signal of the optoelectronic isolation module 111 through the operational amplifier U1 according to the proportionality coefficient K, and is applied between the second terminal and the third terminal of the power tube 12 to turn on the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

Specifically, as an embodiment, as shown in fig. 4, the optoelectronic isolation module 111 includes: the circuit comprises a first resistor R1, a first operational amplifier U1, a second resistor R2, a linear optical coupling module M1, a second operational amplifier U2 and a third resistor R3;

a common junction point between one end of the first resistor R1 and the first end of the power tube 12 is used as a first end of the power tube analog circuit 10, a common junction point between the other end of the first resistor R1 and the third end of the linear optical coupling module M1 is connected to an inverting input end of the first operational amplifier U1, and a non-inverting input end of the first operational amplifier U1 is used as a second end of the power tube analog circuit 10 and is output in a floating mode; the output end of the first operational amplifier U1 is connected to one end of the second resistor R2, the other end of the second resistor R2 is connected to the first end of the linear optical coupling module M1, the second end of the linear optical coupling module M1 is connected to a power supply VCC, and the fourth end of the linear optical coupling module M1 is connected to a floating ground for output; a common joint between the fifth end of the linear optical coupler module M1 and the non-inverting input end of the second operational amplifier U2 and the third end of the power tube 12 is grounded, and is used as the third end of the power tube analog circuit 10; a sixth end of the linear optical coupling module M1 and one end of the third resistor R3 are connected to the inverting input end of the second operational amplifier U2, and a common point between the other end of the third resistor R3 and the output end of the second operational amplifier U2 is connected to the second end of the power tube 12;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power transistor analog circuit 10 is used as an input signal of the optoelectronic isolation module 111, and is amplified by a first operational amplifier U1 and then applied to the linear optical coupling module M1, the linear optical coupling module M1 generates an optical signal, converts the optical signal into an electrical signal, transmits the electrical signal to the second operational amplifier U2 and feeds the electrical signal back to the first operational amplifier U1, and the second operational amplifier U2 scales the electrical signal according to a scaling coefficient K to obtain an output signal of the optoelectronic isolation module 111. The output signal is transmitted between the second end and the third end of the power tube 12 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In the present embodiment, the linear light coupling module M1 includes a light emitting diode LED, a first photodiode PD1, and a second photodiode PD 2. The voltage signal/current signal between the first end and the second end of the power tube analog circuit 10 is used as the input signal of the optoelectronic isolation module 111, and is amplified by the first resistor R1 and the first operational amplifier U1 and then is added to the light emitting diode LED in the linear optical coupling module M1, and the light emitting diode LED is turned on to generate an optical signal. Here, the input signal controls the current of the light emitting diode LED through the first operational amplifier U1 to control the intensity of the light signal. The optical signal is simultaneously collected by the first photodiode PD1 and the second photodiode PD 2. The first photodiode PD1 and the first operational amplifier U1 form negative feedback, so that the stability and the linearity of the signal transmission circuit can be effectively improved. The second photodiode PD2 receives and converts the optical signal into an electrical signal, which is further scaled by the second operational amplifier U2, converted into an output signal of the optoelectronic isolation module 111, and applied between the second terminal and the third terminal of the power transistor 12, so as to turn on the power transistor 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

Optionally, the linear optical coupler module M1 includes, but is not limited to, a linear optical coupler module of HCNR200 series.

Specifically, as an embodiment, as shown in fig. 5, when the signal transmission circuit 11 is an isolated signal transmission circuit, the signal transmission circuit 11 includes a magnetic isolation module 112;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit 10 is used as an input signal of the magnetic isolation module 112, and the magnetic isolation module 112 converts the input signal into an output signal according to an electromagnetic isolation principle and transmits the output signal to a place between a second end and a third end of the power tube 12, so that the power tube 12 is conducted; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In this embodiment, the magnetic isolation module 112 includes a magnetic coupling portion and a magnetic isolation portion. The voltage signal/current signal between the first terminal and the second terminal of the power tube simulation circuit 10 is applied to the magnetic coupling portion of the magnetic isolation module 112 as the input signal of the magnetic isolation module 112. When the magnetic coupling portion generates a magnetic signal according to an input signal, the magnetic isolation portion receives the magnetic signal and generates a current, and outputs an electrical signal according to the proportionality coefficient K as an output signal of the magnetic isolation module 112. The output signal is applied between the second terminal and the third terminal of the power tube 12 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

Specifically, as an embodiment, as shown in fig. 6, the magnetic isolation module 112 includes: a capacitor C1 and a transformer T1;

a common junction point between a first end of the primary winding of the transformer T1 and a first end of the power tube 12 is used as a first end of the power tube analog circuit 10, a second end of the primary winding in the transformer T1 is connected with the capacitor C1, and the other end of the capacitor C1 is used as a second end of the power tube analog circuit 10; a first end of a secondary winding in the transformer T1 is connected to a second end of the power tube 12, and a common junction between the second end of the secondary winding and a third end of the power tube 12 is used as the third end of the power tube analog circuit 10; the first end of the primary winding and the first end of the secondary winding are homonymous ends, and the second end of the primary winding and the second end of the secondary winding are homonymous ends;

in the signal transmission circuit, a voltage signal/current signal between the first terminal and the second terminal of the power tube analog circuit 10 is applied to a primary winding of a transformer T1 as an input signal of the magnetic isolation module 112, a secondary winding of the transformer T1 induces an electrical signal according to the proportionality coefficient K, and is transmitted to between the second terminal and the third terminal of the power tube 12 as an output signal of the magnetic isolation module 112 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In this embodiment, the capacitor C1 and the primary winding of the transformer T1 form a magnetic coupling portion of the magnetic isolation module 112, and the secondary winding of the transformer T1 forms a magnetic isolation portion. The voltage signal/current signal between the first terminal and the second terminal of the power tube simulation circuit 10 is applied to the magnetic coupling portion of the magnetic isolation module 112 as the input signal of the magnetic isolation module 112. The capacitor C1 is a dc blocking capacitor to isolate dc components in the input signal. When the primary winding in the transformer T1 generates a magnetic signal according to an input signal, the secondary winding receives the magnetic signal and induces an electrical signal according to the magnetic signal and a proportionality coefficient K, and the electrical signal is transmitted between the second end and the third end of the power tube 12 as an output signal of the magnetic isolation module 112 to turn on the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

Specifically, as an embodiment, as shown in fig. 7, when the signal transmission circuit 11 is an isolated signal transmission circuit, the signal transmission circuit 11 includes a capacitive isolation module 113;

in the signal transmission circuit, a voltage signal/current signal between a first end and a second end of the power tube analog circuit 10 is used as an input signal of the capacitive isolation module 113, and the capacitive isolation module 113 converts the input signal into an output signal according to a capacitive coupling principle and transmits the output signal to a place between a second end and a third end of the power tube 12, so that the power tube 12 is conducted; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In this embodiment, the capacitive isolation module 113 includes a coupling capacitor. The voltage signal/current signal between the first end and the second end of the power tube analog circuit 10 is used as the input signal of the capacitive isolation module 113 and is added to the coupling capacitor of the capacitive isolation module 113. The coupling capacitor couples the input signal from the front stage to the rear stage, isolates the dc component in the input signal, and then scales the input signal according to the scaling coefficient K to output an electrical signal as an output signal of the capacitive isolation module 113. The output signal is applied between the second terminal and the third terminal of the power tube 12 to conduct the power tube 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

Specifically, as an embodiment, as shown in fig. 8, when the signal transmission circuit 11 is a non-isolated signal transmission circuit, the signal transmission circuit includes a differential operational amplifier circuit 114;

a common junction point between a first signal input end of the differential operational amplifier circuit 114 and a first end of the power tube 12 is used as a first end of the power tube analog circuit 10, and a second signal input end of the differential operational amplifier circuit 114 is used as a second end of the power tube analog circuit 10; the output end of the differential operational amplifier circuit 114 is connected to the second end of the power tube 12, and the common contact between the third input end of the differential operational amplifier circuit 114 and the third end of the power tube 12 is connected to the floating ground for output as the third end of the power tube analog circuit 10;

in the signal transmission circuit, the differential operational amplifier circuit 114 obtains a voltage signal/current signal at a first end of the power transistor analog circuit 10 through a first signal input end, obtains a voltage signal/current signal at a second end of the power transistor analog circuit 10 through a second signal input end, obtains an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal to a position between a second end and a third end of the power transistor 12, so as to enable the power transistor 12 to be conducted; when the power tube 12 is turned on, the power tube analog circuit 10 constitutes a complementary power tube of the power tube 12.

In this embodiment, the voltage signal/current signal between the first terminal and the second terminal of the power transistor analog circuit 10 is respectively applied to the first signal input terminal and the second signal input terminal of the differential operational amplifier circuit 114, wherein the first signal input terminal is a positive phase input terminal, and the second signal input terminal is an inverted phase input terminal. The differential operational amplifier circuit 114 calculates a difference between signals at the first signal input terminal and the second signal input terminal to obtain an input signal, and then scales the input signal according to the scaling coefficient K to obtain an output signal, wherein the output signal is applied between the second terminal and the third terminal of the power transistor 12 to turn on the power transistor 12; when the power tube 12 is turned on, the power tube analog circuit 10 forms a power tube with high power complementary to the power tube 12.

In any of the above embodiments of fig. 1 to 8, the power transistor 12 includes, but is not limited to, an N-channel MOS transistor and an NPN-type transistor. When the power transistor 12 is an N-channel MOS transistor, the signal transmission circuit 11 controls a voltage source of the N-channel MOS transistor through a voltage, and the power transistor analog circuit 10 forms a P-channel MOS transistor with a high power, which is complementary to the N-channel MOS transistor. When the power transistor 12 is an NPN-type triode, the signal transmission circuit 11 controls a current source of the NPN-type triode through a current, and the power transistor analog circuit 10 forms a PNP-type triode with high power, which is complementary to the NPN-type triode.

Specifically, as an embodiment, as shown in fig. 9, when the power transistor is an N-channel MOS transistor T01, a common junction between a first terminal of the signal transmission circuit 11 and a drain of the N-channel MOS transistor T01 serves as a source of the power transistor analog circuit 10, and a second terminal of the signal transmission circuit 11 serves as a gate of the power transistor analog circuit 10; the third end of the signal transmission circuit 11 is connected with the gate of the N-channel MOS transistor T01, and the common junction point between the fourth end of the signal transmission circuit 11 and the source of the N-channel MOS transistor T01 serves as the drain of the power transistor analog circuit 10;

the ratio of an input signal between the first end and the second end of the signal transmission circuit 11 to an output signal between the third end and the fourth end of the signal transmission circuit 11 is a proportionality coefficient K, wherein the proportionality coefficient K is a positive integer;

when a voltage signal exists between the source and the gate of the power transistor analog circuit 10, the signal transmission circuit 11 obtains the voltage signal between the source and the gate of the power transistor analog circuit 10 as an input signal, converts the input signal into an output signal according to a proportionality coefficient K, and transmits the output signal between the gate and the source of the N-channel MOS transistor T01 to turn on the N-channel MOS transistor T01, so that the power transistor analog circuit 10 forms a P-channel MOS transistor complementary to the N-channel MOS transistor T01.

For the circuit structure and the implementation principle of the signal transmission circuit 11, reference is specifically made to the description of the above embodiments, and details are not repeated here. When the voltage between the source and the gate of the power transistor analog circuit 10 is changed, the voltage between the gate and the source of the N-channel MOS transistor T01 is changed. For an external circuit, the power transistor analog circuit 10 constitutes a P-channel MOS transistor complementary to the N-channel MOS transistor T01, wherein a first end of the power transistor analog circuit 10 constitutes a source of the P-channel MOS transistor, a second end constitutes a gate of the P-channel MOS transistor, and a third end constitutes a drain of the P-channel MOS transistor.

Specifically, as shown in fig. 10, when the power transistor 12 is an NPN transistor VT01, a common junction between a first terminal of the signal transmission circuit 11 and a collector of the NPN transistor VT01 serves as an emitter of the power transistor analog circuit 10, and a second terminal of the signal transmission circuit 11 serves as a base of the power transistor analog circuit 10; the third end of the signal transmission circuit 11 is connected with the base electrode of the NPN type triode VT01, and the common junction between the fourth end of the signal transmission circuit 11 and the emitter electrode of the NPN type triode VT01 is used as the collector electrode of the power transistor analog circuit 10;

the ratio of the input signal I1 between the first terminal and the second terminal of the signal transmission circuit 11 to the output signal I2 between the third terminal and the fourth terminal of the signal transmission circuit 11 is a proportionality coefficient K, wherein the proportionality coefficient K is a positive integer;

when a current signal exists between the emitter and the base of the power tube analog circuit 10, the signal transmission circuit 11 obtains the current signal between the emitter and the base of the power tube analog circuit 10 as an input signal I1, converts the input signal I1 into an output signal I2 according to a proportionality coefficient K, and then transmits the output signal I2 to a position between the base and the emitter of the NPN type triode VT01 so as to turn on the NPN type triode VT01, and the power tube analog circuit 10 forms a PNP type triode complementary to the NPN type triode VT 01.

For the circuit structure and the implementation principle of the signal transmission circuit 11, reference is specifically made to the description of the above embodiments, and details are not repeated here. Changing the current between the emitter and the base of the power tube analog circuit 10 changes the current between the base and the emitter of the NPN transistor VT 01. For an external circuit, the power tube analog circuit 10 forms a PNP type triode complementary to the NPN type triode VT01, wherein a first end of the power tube analog circuit 10 forms an emitter of the PNP type triode, a second end forms a base of the PNP type triode, and a third end forms a collector of the PNP type triode.

Specifically, as an implementation manner, as shown in fig. 11, an output stage circuit of a power amplifier provided in an embodiment of the present invention includes: an N-channel MOS transistor T02 and a power tube analog circuit 10;

a common joint between the grid of the N-channel MOS transistor T02 and the grid of the power tube analog circuit 10 is used as an input end of the output stage circuit and is connected with an output end of a voltage amplification stage of the power amplifier;

the common junction point between the source electrode of the N-channel MOS transistor T02 and the source electrode of the power tube analog circuit 10As the output end of the output stage circuit, a load R is connected_L；

The drain of the N-channel MOS transistor T02 is connected to the positive electrode of the power supply, and the drain of the power transistor analog circuit 10 is connected to the negative electrode of the power supply.

The power transistor simulation circuit is a P-channel MOS transistor obtained by simulation based on the N-channel MOS transistor T01, for details, refer to the description of the embodiments in fig. 1 to 9, and are not described herein again. In this embodiment, the power transistor simulation circuit 10 is obtained by constructing a signal transmission circuit and simulating an N-channel MOS transistor with high power into a P-channel MOS transistor with high power. The power tube analog circuit 10 and the N-channel MOS transistor in the prior art are used for constructing the output stage circuit of the power amplifier, the output stage circuit based on the full N-channel MOS transistor is realized, the problems that the high-power P-channel MOS transistor in the prior art is few in variety and difficult to purchase, the construction of the high-voltage high-power output stage circuit is difficult, the problems that the output stage circuit constructed based on the existing composite tube is not high in voltage withstanding degree and limited in output power are solved, and the voltage withstanding degree and the output power of the output stage circuit are improved.

Specifically, as an implementation manner, as shown in fig. 12, an output stage circuit of a power amplifier provided in an embodiment of the present invention includes: an NPN type triode VT02 and a power tube simulation circuit 10;

a common junction point between the base electrode of the NPN type triode VT02 and the base electrode of the power tube analog circuit 10 is used as an input end of the output stage circuit and is connected with an output end of a voltage amplification stage of the power amplifier;

the common joint between the emitter of the NPN type triode VT02 and the emitter of the power tube analog circuit 10 is used as the output end of the output stage circuit and is connected with a load R_L；

The collector of the NPN type triode VT02 is connected to the positive electrode of the power supply, and the collector of the power transistor analog circuit 10 is connected to the negative electrode of the power supply.

The power transistor analog circuit 10 is a PNP transistor obtained by simulation based on an NPN transistor VT01, for details, please refer to the description of the embodiments in fig. 1 to 8 and 10, which is not repeated herein. In this embodiment, a signal transmission circuit is constructed, and an NPN-type transistor with high power is simulated into a PNP-type transistor with high power, so as to obtain the power transistor simulation circuit 10. The output stage circuit of the power amplifier is constructed by using the power tube analog circuit 10 and the NPN type triode in the prior art, so that the output stage circuit based on the full NPN type triode is realized, the problems that the high-power PNP type triode in the prior art is few in variety and difficult to purchase, the construction of the high-voltage high-power output stage circuit is difficult, the problems that the output stage circuit constructed based on the existing composite tube is not high in voltage withstanding degree and limited in output power are solved, and the voltage withstanding degree and the output power of the output stage circuit are improved.

Specifically, as an implementation manner, as shown in fig. 13, a power amplifier provided for an embodiment of the present invention includes: an N-channel MOS transistor T02, a power tube analog circuit 10, a third operational amplifier U3, a fourth resistor R4 and a fifth resistor R5;

a non-inverting input end of the third operational amplifier U3 is connected to an input voltage, an inverting input end of the third operational amplifier U3 is connected to the fifth resistor R5, and the other end of the fifth resistor R5 is connected to a floating output;

the output end of the third operational amplifier U3 is respectively connected with the gate of the N-channel MOS transistor T02 and the gate of the power tube analog circuit 10;

a common junction point between the source electrode of the N-channel MOS transistor T02 and the source electrode of the power tube analog circuit 10 is connected with a load and the fourth resistor R4, and the other end of the fourth resistor R4 is connected with the inverting input end of the third operational amplifier U3;

the drain of the N-channel MOS transistor T02 is connected to the positive electrode of the power supply, and the drain of the power transistor analog circuit 10 is connected to the negative electrode of the power supply.

The power transistor simulation circuit 10 is a P-channel MOS transistor simulated based on the N-channel MOS transistor T01, and please refer to the description of the embodiments in fig. 1 to 9 for details, which are not repeated herein. In this embodiment, the power transistor analog circuit 10 is used as a P-channel MOS transistor, an output stage circuit is constructed by combining an N-channel MOS transistor, and a negative feedback circuit composed of a fourth resistor R4, a fifth resistor R5, and a third operational amplifier U3 is added to obtain a power amplifier based on a full N-channel MOS transistor. In the power amplifier, the relationship between the output voltage Uo and the input voltage Ui is: uo ═ Ui × R1/R2. The power amplifier does not need a high-power P-channel MOS transistor, is easier to produce, improves the withstand voltage degree and the output power of an output stage circuit, and solves the problems of low withstand voltage degree and limited output power of the power amplifier constructed based on the existing composite tube.

Specifically, as an implementation manner, as shown in fig. 13, a power amplifier provided for an embodiment of the present invention includes: the NPN type triode VT02, the power tube analog circuit 10, the third operational amplifier U3, the fourth resistor R4 and the fifth resistor R5;

a non-inverting input end of the third operational amplifier U3 is connected to an input voltage, an inverting input end of the third operational amplifier U3 is connected to the fifth resistor R5, and the other end of the fifth resistor R5 is connected to a floating output;

the output end of the third operational amplifier U3 is respectively connected to the base of the NPN transistor VT02 and the base of the power transistor analog circuit 10;

a common junction point between the emitter of the NPN type triode VT02 and the emitter of the power tube analog circuit 10 is connected to a load and the fourth resistor R4, and the other end of the fourth resistor R4 is connected to the inverting input terminal of the third operational amplifier U3;

the collector of the NPN type triode VT02 is connected to the positive electrode of the power supply, and the collector of the power transistor analog circuit 10 is connected to the negative electrode of the power supply.

The power transistor analog circuit 10 is a PNP transistor obtained by simulation based on an NPN transistor VT01, for details, please refer to the description of the embodiments in fig. 1 to 8 and 10, which is not repeated herein. In this embodiment, the power transistor analog circuit 10 is used as a PNP type triode, an NPN type triode is combined to construct an output stage circuit, and a negative feedback circuit composed of a fourth resistor R4, a fifth resistor R5, and a third operational amplifier U3 is added to obtain a power amplifier based on a full NPN type triode. In the power amplifier, the relationship between the output voltage Uo and the input voltage Ui is: uo ═ Ui × R1/R2. The power amplifier does not need a high-power PNP type triode, is easier to produce, improves the withstand voltage degree and the output power of an output stage circuit, and solves the problems of low withstand voltage degree and limited output power of the power amplifier constructed based on the existing composite tube.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.