A class ab output dual-tube synchronous combining power amplifier circuit

Abstract

The application discloses a double-tube synchronous combined power amplifier circuit of class A output. The double-tube synchronous combined power amplifier circuit of class A output comprises a shot voltage signal input end of a class A shot output power amplifier circuit and a front drive voltage signal input end of a front-stage drive circuit, which are respectively connected with two-way output ends of an audio branch circuit and are connected with a one-way output end of a bias voltage circuit through input ends of the audio branch circuit. A load output end of the front-stage drive circuit is connected with an absorbing load circuit to the ground. A drive signal output end outputs a drive signal which is connected with a drive signal input end of a class A shot power amplifier circuit. Shot power signals output from a shot power output end and amplification power signals output from an amplification power output end are respectively connected with two-way input ends of a power combining circuit. The technical scheme of the application realizes the reduction of distortion signals in a class A combined power signal.

Description

Technical Field

[0001] This invention relates to the field of audio power amplifier circuit technology, and more particularly to a dual-transistor synchronous combining power amplifier circuit with Class A output. Background Technology

[0002] In audio power amplifier circuits, power output circuits currently utilize complementary emitter follower output circuits, complementary feedback output circuits, quasi-complementary output circuits, and multi-stage output circuits combining these circuits. Efficiency is improved and performance similar to Class A single-transistor power amplifier circuits is achieved through the separate switching of complementary symmetrical transistors and the setting of quiescent current. This is achieved through Class B, Class AB, or Class A complementary symmetrical transistor technology, and similar Class A technologies. XD power amplifier circuits employ translational crossover distortion technology to change the voltage position of crossover distortion. Class H power amplifier circuits utilize dynamic acceleration of the power supply voltage. Class G power amplifier circuits switch from a low-voltage power supply operating at a small output to a high-voltage power supply operating at a larger output to reduce internal power consumption and improve efficiency. However, this results in a linearity worse than Class B. Additionally, totem-pole circuit technology still uses a two-transistor complementary switching and conduction technique for voltage amplification. The application of complementary transistors to achieve performance similar to Class A single-transistor power amplifier circuits, along with the separate switching of complementary transistors, introduces crossover distortion due to the discontinuity of the switching currents of the complementary symmetrical transistors. In addition, while Class D digital power amplifier circuit technology improves efficiency, it also introduces distortion and gain imbalance and distortion at high and low frequencies. Therefore, it always differs from the audio distortion characteristics of Class A single-tube power amplifier circuits with continuous operating current.

[0003] Therefore, how to achieve distortion characteristics similar to Class A audio amplifier circuits while also obtaining high amplification efficiency is a topic worthy of in-depth research in the field of audio power amplifier circuits. Summary of the Invention

[0004] This invention provides a dual-transistor synchronous combining power amplifier circuit with Class A output to reduce the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combining power amplifier circuit with Class A output.

[0005] According to one aspect of the present invention, a dual-transistor synchronous combining power amplifier circuit with Class A output is provided. The dual-transistor synchronous combining power amplifier circuit with Class A output provided in the embodiments of the present invention includes: a pre-stage driver circuit, an absorption load circuit, a Class A emitter follower output power amplifier circuit, a Class A emitter follower amplification power amplifier circuit, a pre-stage driver negative feedback circuit, an audio splitter circuit, a bias voltage circuit, and a power combining circuit. Among them, the emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-drive voltage signal input terminal of the pre-drive circuit are respectively connected to the two output terminals of the audio splitter circuit, and connected to one output terminal of the bias voltage circuit through the input terminal of the audio splitter circuit. Alternatively, the input terminals of the follower voltage signal and the input terminals of the preceding voltage signal can be directly connected to the two output terminals of the bias voltage circuit respectively. The drive power signal output from the load output terminal of the pre-amplifier driver circuit is connected to the load absorption circuit to ground; the drive signal output from the drive signal output terminal of the pre-amplifier driver circuit is connected to the drive signal input terminal of the Class A emitter follower power amplifier circuit. The emitter-follower power signal output from the emitter-follower power amplifier circuit and the amplified power signal output from the amplified power amplifier circuit are respectively connected to the two input terminals of the power combiner circuit. At the combined output terminal of the dual-transistor synchronous combined power amplifier circuit, the DC bias voltage of the drive signal output terminal of the pre-stage drive circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter-follower power signal output from the class-A emitter-follower power amplifier circuit and the amplified power signal output from the class-A emitter-follower power amplifier circuit to be synchronously output at the output terminal of the combiner circuit, thereby improving the overall circuit efficiency. The amplified power signal extracted by the pre-stage driver negative feedback circuit through the feedback output terminal of the Class A emitter follower power amplifier circuit is connected to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A dual-transistor synchronous combined power amplifier circuit.

[0006] Optionally, the pre-stage drive circuit includes: a pre-stage PNP or NPN drive circuit composed of a PNP or NPN transistor, a resistor, a constant current source, and a load absorption circuit. The pre-stage PNP driver circuit connects the emitter of the PNP transistor to a constant current source connected to the positive power supply, and the collector of the PNP transistor is connected to a resistor connected to ground or to the negative power supply. The drive power signal output from the load output terminal of one branch of the connection between the emitter of the PNP transistor and the constant current source is connected to ground via a load absorption circuit. The other branch of the connection between the emitter of the PNP transistor and the constant current source serves as the feedback input terminal of the pre-stage PNP driver circuit. The connection between the collector of the PNP transistor and the resistor serves as the drive signal output terminal of the pre-stage PNP driver circuit. The base of the PNP transistor or the connection between the base of the PNP transistor and the capacitor connected to ground serves as the pre-driver voltage signal input terminal of the pre-stage PNP driver circuit. The pre-driver voltage signal input terminal of the pre-stage PNP driver circuit is directly connected to one output terminal of the dual-output bias voltage circuit, or it can be connected to one output terminal of the single-output bias voltage circuit or one output terminal of the dual-output bias voltage circuit via one output terminal of the connected audio branch circuit. In one configuration, the pre-stage NPN driver circuit connects the emitter of the NPN transistor to a constant current source connected to ground or a negative / positive power supply, and the collector of the NPN transistor connected to a resistor connected to a positive power supply. The drive power signal output from the load output terminal of one branch at the connection between the NPN transistor's emitter and the constant current source is connected to ground via a load absorption circuit. The other branch at the connection between the NPN transistor's emitter and the constant current source serves as the feedback input terminal of the pre-stage NPN driver circuit. The connection between the NPN transistor's collector and the resistor serves as the drive signal output terminal of the pre-stage NPN driver circuit. The base of the NPN transistor, or the base of the NPN transistor connected to a capacitor connected to ground, or the connection between the base of the power supply and the capacitor, serves as the pre-driver voltage signal input terminal of the pre-stage NPN driver circuit. The pre-driver voltage signal input terminal of the pre-stage NPN driver circuit can be directly connected to one output terminal of a dual-output bias voltage circuit; or, through one output terminal of a connected audio branch circuit, and via the input terminal of the audio branch circuit, it can be connected to a single output terminal of a single-output bias voltage circuit; or it can be connected to one output terminal of a dual-output bias voltage circuit. Among them, the DC bias voltage at the connection between the collector and the resistor in the front-end PNP or NPN drive circuit meets the DC bias voltage requirements of the drive signal input terminal of the Class A emitter follower power amplifier circuit. The audio splitter circuit consists of a circuit that is split into two. The load absorption circuit consists of a capacitor connected in series with a resistor and grounded. The constant current source includes a single-transistor or dual-transistor constant current source circuit, or a mirror constant current source circuit; The bias voltage circuit includes: a dual-output or single-output bias voltage circuit; the dual-output bias voltage circuit is composed of a multiplier circuit, or a resistor, or a resistor in series with a diode; the single-output bias voltage circuit is composed of removing the multiplier circuit, or removing the resistor, or removing the resistor in series with a diode, and short-circuiting the two output terminals to form a single output terminal. Specifically, by using the DC bias voltage at the output terminal of the drive signal of the pre-stage drive circuit, or by using the voltage difference between the two output terminals of the bias voltage circuit, the DC bias voltage of the base of the final NPN or PNP transistor in the Class A emitter follower power amplifier circuit is made synchronously equal to or nearly equal to the DC bias voltage of the base of the final NPN or PNP transistor in the Class A emitter follower power amplifier circuit. At the combined output terminal of the dual-transistor synchronous combined power amplifier circuit, the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the Class A emitter follower power amplifier circuit are synchronously output to achieve a Class A combined power signal and improve the overall circuit efficiency. Furthermore, the amplified power signal extracted by the pre-stage drive negative feedback circuit is fed to the feedback input terminal of the pre-stage drive circuit, thereby reducing the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combined power amplifier circuit.

[0007] Optionally, the Class A emitter follower output power amplifier circuit includes: a Class A NPN or PNP emitter follower output power amplifier circuit composed of a single NPN transistor or a single PNP transistor, or a composite NPN transistor or a composite PNP transistor, or a multi-stage composite NPN transistor or a multi-stage composite PNP transistor and a resistor. The Class A NPN or PNP emitter follower power amplifier circuit is composed of a single NPN transistor or a single PNP transistor, or by connecting the base of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor to the emitter of the corresponding stage NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding stage NPN or PNP transistor in the previous stage, an output voltage regulating terminal for the composite or multi-stage composite NPN or PNP transistor in the Class A NPN or PNP emitter follower power amplifier circuit is formed. The emitter of the final stage NPN or PNP transistor is used to form the emitter of a composite or multi-stage composite NPN or PNP transistor. The emitter of a single-channel, composite, or multi-stage composite NPN or PNP transistor is connected to the emitter follower power signal output by the current-limiting power resistor, forming the emitter follower power output terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. A voltage regulating resistor is connected to the emitter of the corresponding NPN or PNP transistor in the final stage of the composite or multi-stage composite NPN or PNP transistor, or connected to the emitter follower power output terminal of the Class A NPN or PNP emitter follower output power amplifier circuit. The collector of the final-stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the corresponding NPN or PNP transistor in the previous stage to form the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor is the power supply terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. The power supply terminal of the Class A NPN emitter follower output power amplifier circuit is connected to a positive power supply, and the power supply terminal of the Class A PNP emitter follower output power amplifier circuit is connected to ground or a negative power supply. The base of the input stage NPN or PNP transistor, whether a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor. This connection point serves as the emitter follower voltage signal input terminal for the Class A NPN or PNP emitter follower output power amplifier circuit.

[0008] Optionally, the Class A emitter follower power amplifier circuit includes: a Class A NPN or PNP emitter follower amplifier circuit composed of a single NPN transistor or a single PNP transistor, or a composite NPN transistor or a composite PNP transistor, or a multi-stage composite NPN transistor or a multi-stage composite PNP transistor and a resistor. A Class A NPN or PNP emitter follower amplifier circuit is composed of a single NPN or PNP transistor whose emitter is connected to a current-limiting power resistor; or, it is composed of a composite or multi-stage composite NPN or PNP transistor whose base is connected to the emitter of the corresponding NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding NPN or PNP transistor in the previous stage, an amplification and voltage regulation terminal for the composite or multi-stage composite NPN or PNP emitter follower power amplifier circuit is formed. The amplification and voltage regulation terminal of the PN or PNP transistor is connected to the resistance terminal of the voltage regulation resistor, and is interconnected with the resistance terminal of the current-limiting power resistor connected to the emitter of the NPN or PNP transistor corresponding to the output final stage of the composite or multi-stage composite NPN or PNP transistor, forming a resistance terminal in the composite or multi-stage composite NPN or PNP transistor; wherein, the resistance terminal of a single-channel NPN or PNP transistor or the resistance terminal of a composite or multi-stage composite NPN or PNP transistor forms the power supply terminal of the Class A emitter follower power amplifier circuit; wherein, the power supply terminal of the Class A NPN emitter follower power amplifier circuit is connected to ground or a negative power supply, and the power supply terminal of the Class A PNP emitter follower power amplifier circuit is connected to a positive power supply. In this circuit, the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor, or the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor via a resistor, thus forming the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor is connected to the amplified power signal output from the amplified current-limiting power resistor, forming the amplified power output terminal in the Class A NPN or PNP emitter follower power amplifier circuit. The connection point between the collector of a single-channel or composite or multi-stage composite NPN or PNP transistor and the amplified current-limiting power resistor is the feedback output terminal of the Class A NPN or PNP emitter follower power amplifier circuit. Among them, the base of the input stage NPN or PNP transistor in a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then connected to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor, which is the drive signal input terminal of the Class A NPN or PNP emitter follower power amplifier circuit.

[0009] Optionally, the pre-stage driver negative feedback circuit includes: a phase-shifting circuit formed by a capacitor connected in series with a feedback resistor, or a feedback resistor in the pre-stage driver negative feedback circuit connected in parallel with a phase-shifting capacitor, or a phase-shifting circuit formed by a feedback resistor in the pre-stage driver negative feedback circuit connected in series with a phase-shifting capacitor; the capacitor terminal or feedback resistor terminal of the pre-stage driver negative feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit, and the corresponding feedback resistor terminal or capacitor terminal of the pre-stage driver negative feedback circuit is connected to the feedback input terminal of the pre-stage driver circuit.

[0010] Optionally, the matching of the pre-amplifier PNP or NPN drive circuit with the Class A NPN or PNP emitter follower output power amplifier circuit and the Class A NPN or PNP emitter follower power amplifier circuit is as follows: The pre-stage PNP driver circuit is matched and combined with a Class A NPN emitter follower output power amplifier circuit and a Class A NPN emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Alternatively, the pre-stage NPN driver circuit is matched and combined with a Class A PNP emitter follower output power amplifier circuit and a Class A PNP emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Furthermore, the emitter follower power signal output by the Class A NPN or PNP emitter follower output power amplifier circuit and the amplified power signal output by the Class A NPN or PNP emitter follower amplification power amplifier circuit are satisfied. At the combining output terminal of the Class A output dual-transistor synchronous combining power amplifier circuit, the synchronous output of the Class A combined power signal is realized, thereby improving the efficiency of the entire circuit. In addition, the amplified power signal extracted by the pre-stage driver negative feedback circuit is sent to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A output dual-transistor synchronous combining power amplifier circuit.

[0011] Optionally, based on the Class A output dual-transistor synchronous combined power amplifier circuit, the voltage regulating resistor connected to the voltage regulating terminal of the composite or multi-stage composite NPN or PNP transistor in the Class A emitter follower power amplifier circuit is removed. Instead, the base of the constant current controlled NPN or PNP transistor is connected to the connection point between the emitter of the corresponding NPN or PNP transistor in the Class A emitter follower power amplifier circuit and the current limiting power resistor. The emitter of the constant current controlled NPN or PNP transistor is then connected to the power supply terminal of the Class A emitter follower power amplifier circuit, forming the modified power supply terminal of the Class A emitter follower power amplifier circuit. The collector of the constant current controlled NPN or PNP transistor is then connected to the connection point between the base of the corresponding NPN or PNP transistor in the final stage of the single-stage or multi-stage composite NPN or PNP transistor output in the Class A emitter follower power amplifier circuit and the emitter of the corresponding NPN or PNP transistor in the previous stage. Alternatively, the collector connection of the constant current-controlled NPN or PNP transistor in the Class A emitter follower power amplifier circuit can be modified. The base of the corresponding NPN or PNP transistor in the final stage of the output circuit can be connected to the emitter of the corresponding NPN or PNP transistor in the previous stage via a control resistor, which is then connected to the positive power supply, ground, or negative power supply. The control resistor is then connected to the midpoint voltage connection of an added voltage divider resistor, forming the modified Class A emitter follower power amplifier circuit. The constant current source circuit and absorption load circuit in the pre-stage driver circuit are removed, as are the capacitors in the pre-stage driver feedback circuit. The feedback resistor in the pre-stage driver feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit, or an additional emitter resistor is connected to the midpoint voltage connection of the additional voltage divider circuit at the connection point between the emitter and the feedback resistor in the pre-stage driver circuit, forming the modified pre-stage driver circuit and the modified pre-stage driver feedback circuit; wherein, the emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-drive voltage signal input terminal of the modified pre-stage driver circuit can only be connected to the two output terminals of the two-way output bias voltage circuit respectively, forming a Class A output single-tube synchronous constant current power amplifier circuit; At the combined output terminal of the single-transistor synchronous constant current power amplifier circuit with Class A output, the DC bias voltage at the drive signal output terminal of the modified pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the modified Class A emitter follower power amplifier circuit to be synchronously output at the output terminal of the combined circuit, thereby improving the efficiency of the entire circuit. Furthermore, the amplified power signal extracted by the pre-stage driver negative feedback circuit is fed to the feedback input terminal of the pre-stage driver circuit to reduce the distortion signal in the synchronously output Class A combined power signal of the single-transistor synchronous constant current power amplifier circuit with Class A output.

[0012] The technical solution of this invention uses the DC bias voltage at the drive signal output terminal of the pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, to synchronize the output of the Class A emitter follower power amplifier circuit and the output of the Class A emitter follower amplifier power amplifier circuit at the output terminal of the combining circuit, thereby achieving synchronous output of the Class A combined power signal and improving the overall circuit efficiency. The amplified power signal extracted by the pre-stage driver negative feedback circuit through the feedback output terminal of the Class A emitter follower amplifier power amplifier circuit is connected to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combining power amplifier circuit.

[0013] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A circuit diagram of a dual-transistor synchronous combining power amplifier circuit with Class A output provided in an embodiment of the present invention; Figure 2 A circuit diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; Figure 3 A circuit diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; Figure 4 This invention provides an application circuit for a Class A output NPN dual-transistor synchronous combining power amplifier circuit. Figure 5 A schematic diagram of an audio power amplifier circuit with negative feedback is provided for the relevant prior art; Figure 6 A circuit diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; Figure 7 A circuit diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; Figure 8 The circuit structure diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in the embodiment of the present invention. Detailed Implementation

[0016] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0017] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0018] Figure 1 A circuit diagram of a dual-transistor synchronous combining power amplifier circuit with Class A output provided in an embodiment of the present invention; Figure 2 A circuit diagram of another type A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; Figure 3 This is a circuit diagram of another Class A output dual-transistor synchronous combining power amplifier circuit provided by an embodiment of the present invention. This embodiment of the present invention is applicable to scenarios involving reducing harmonic distortion in power amplifier circuits. For example, it can be used to reduce harmonic distortion in audio power amplifier circuits. Figure 1 , Figure 2 and Figure 3 As shown, the Class A output dual-transistor synchronous combining power amplifier circuit of this embodiment includes: a pre-stage driver circuit 1, an absorption load circuit 12, a Class A emitter follower output power amplifier circuit 3, a Class A emitter follower amplification power amplifier circuit 4, a pre-stage driver negative feedback circuit 5, an audio branch circuit 2, a bias voltage circuit, and a power combining circuit 6. The emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit 3 and the pre-driver voltage signal input terminal of the pre-stage driver circuit 1 are respectively connected to the two output terminals of the audio branch circuit 2, and connected to one output terminal of the bias voltage circuit via the input terminal of the audio branch circuit 2. Alternatively, the emitter follower voltage signal input terminal and the pre-driver voltage signal input terminal are directly connected to the two output terminals of the bias voltage circuit, respectively. The drive power signal output from the load output terminal of the pre-stage driver circuit 1 is connected to ground via the absorption load circuit 12; the drive signal output from the drive signal output terminal of the pre-stage driver circuit 1 is connected to the drive signal input terminal of the Class A emitter follower amplification power amplifier circuit 4.

[0019] The emitter-follower power signal output from the emitter-follower power output terminal of Class A emitter-follower power amplifier circuit 3 and the amplified power signal output from the amplified power output terminal of Class A emitter-follower power amplifier circuit 4 are respectively connected to the two input terminals of the power combiner circuit 6. At the combiner output terminal of the combined Class A output dual-transistor synchronous combiner power amplifier circuit, the DC bias voltage of the drive signal output terminal of the pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter-follower power signal output from Class A emitter-follower power amplifier circuit 3 and the amplified power signal output from Class A emitter-follower power amplifier circuit 4 to be synchronously output at the output terminal of the combiner circuit, thereby improving the overall circuit efficiency. The amplified power signal extracted by the pre-stage driver negative feedback circuit 5 through the feedback output terminal of Class A emitter-follower power amplifier circuit 4 is connected to the feedback input terminal of the pre-stage driver circuit 1, thereby reducing the distortion signal in the synchronously output Class A combiner power signal of the dual-transistor synchronous combiner power amplifier circuit.

[0020] In this embodiment, reference Figure 1 , Figure 2 and Figure 3 The pre-stage drive circuit 1 includes a PNP or NPN transistor 11, a resistor, a constant current source 13, and a load absorption circuit 12, forming a pre-stage PNP or NPN drive circuit.

[0021] In this circuit, the pre-stage PNP driver circuit 1 connects the emitter of PNP transistor 11 to the constant current source 13 and then to the positive power supply. The collector of PNP transistor 11 is connected to ground or the negative power supply via resistor R203. The drive power signal output from the load output terminal of one branch at the connection between the emitter of PNP transistor 11 and the constant current source 13 is connected to ground via the absorption load circuit 12. The other branch at the connection between the emitter of PNP transistor 11 and the constant current source serves as the feedback input terminal of the pre-stage PNP driver circuit 1. The connection between the collector of PNP transistor 11 and resistor R203 forms the pre-stage PNP driver circuit. The drive signal output terminal of circuit 1, the base of PNP transistor 11 or the connection point between the base of PNP transistor 11 and the capacitor to ground, constitutes the pre-drive voltage signal input terminal of the pre-stage PNP drive circuit 1; wherein, the pre-drive voltage signal input terminal of the pre-stage PNP drive circuit 1 is directly connected to one output terminal of the dual-output bias voltage circuit, or connected to one output terminal of the audio branch circuit 2, and then connected to one output terminal of the single-output bias voltage circuit or one output terminal of the dual-output bias voltage circuit through the input terminal of the audio branch circuit 2.

[0022] The DC bias voltage at the connection between the collector and resistor R203 in the pre-stage PNP driver circuit 1 meets the DC bias voltage requirement of the drive signal input terminal of the Class A emitter follower power amplifier circuit 4.

[0023] The audio branch circuit 2 consists of a circuit that is split into two. The load absorption circuit 12 consists of a capacitor C201 connected in series with a resistor R202 and grounded. The constant current source 13 includes a dual-transistor constant current source circuit.

[0024] The DC bias voltage at the output terminal of the drive signal of the pre-stage drive circuit 1, or the voltage difference between the two output terminals of the bias voltage circuit, makes the base DC bias voltage of the final NPN transistor of the Class A emitter follower power amplifier circuit 3 synchronously equal to or nearly equal to the base DC bias voltage of the final NPN transistor in the Class A emitter follower power amplifier circuit 4. At the combined output terminal of the dual-transistor synchronous combined power amplifier circuit, the emitter follower power signal output by the Class A emitter follower power amplifier circuit 3 and the amplified power signal output by the Class A emitter follower power amplifier circuit 4 achieve synchronous output of the Class A combined power signal, improving the overall circuit efficiency. Furthermore, the amplified power signal extracted by the pre-stage drive negative feedback circuit is fed to the feedback input terminal of the pre-stage drive circuit, reducing the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combined power amplifier circuit.

[0025] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, specifically, the Class A emitter follower output power amplifier circuit 3 can utilize two stages of composite NPN transistors, such as... Figure 1 In the middle, or three-stage composite NPN transistor, such as Figure 2 , Figure 3 As shown in the figure, by analogy, an A-class NPN emitter follower output rate amplifier circuit 3 can also be formed by using an N-class composite NPN transistor and a resistor; Among them, the Class A NPN emitter follower output power amplifier circuit 3 uses two stages of composite NPN transistors, such as Figure 1 As shown. Or a three-stage composite NPN transistor, such as... Figure 2 , Figure 3As shown in the diagram, the base of the final output NPN transistor in a multi-stage NPN transistor array is connected to the emitter of the corresponding NPN transistor in the previous stage. At the connection point between the base of the final output NPN transistor and the emitter of the corresponding NPN transistor in the previous stage, the output voltage regulation terminal of the two- or three-stage composite NPN transistors in the Class A NPN emitter follower power amplifier circuit 3 is formed. The emitter of the final output NPN transistor in the two- or three-stage composite NPN transistor array forms the emitter of the two- or three-stage composite NPN transistor array. The emitter of the two- or three-stage composite NPN transistor array is connected to the emitter follower power signal output by the output current-limiting power resistor, forming the emitter follower power output terminal of the Class A NPN emitter follower power amplifier circuit 3. A voltage regulating resistor is connected to the emitter of the corresponding NPN transistor in the final output stage of the two- or three-stage composite NPN transistor array, or connected to the emitter follower power output terminal of the Class A NPN emitter follower power amplifier circuit 3, through the output voltage regulating terminal of the two- or three-stage composite NPN transistor array.

[0026] The collector of the final NPN transistor in a two- or three-stage composite NPN transistor is connected to the collector of the corresponding NPN transistor in the previous stage, forming the collector of the two- or three-stage composite NPN transistor. The collector of this composite NPN transistor serves as the power supply terminal of the Class A NPN emitter follower output power amplifier circuit 3. The power supply terminal of the Class A NPN emitter follower output power amplifier circuit 3 is connected to a positive power supply.

[0027] Among them, the base of the input stage NPN transistor of the two-stage or three-stage composite NPN transistor, or the base of the input stage NPN transistor connected to the collector of the input stage NPN transistor, forming the connection point between the base of the input stage NPN transistor and the capacitor, is the emitter follower voltage signal input terminal of the Class A NPN emitter follower output power amplifier circuit 3.

[0028] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, specifically, the Class A emitter follower power amplifier circuit 4 is implemented in various ways, including: using a single NPN transistor, a composite NPN transistor, or a multi-stage composite NPN transistor and resistors to form the Class A NPN emitter follower power amplifier circuit 4. For example... Figure 1 , Figure 2 The Class A NPN emitter follower amplifier circuit 4 consists of two-stage composite NPN transistors and resistors. Figure 3 The Class A NPN emitter follower amplifier circuit 4 is composed of a three-stage composite NPN transistor and a resistor.

[0029] The Class A NPN emitter follower amplifier circuit 4 is composed of a single NPN transistor whose emitter is connected to a current-limiting power resistor, or a composite or multi-stage composite NPN transistor whose base is connected to the emitter of the corresponding NPN transistor in the previous stage. The connection between the base of the final output stage NPN transistor and the emitter of the corresponding previous stage forms the amplification and voltage regulation terminal of the composite or multi-stage composite NPN transistor in the Class A NPN emitter follower amplifier circuit. The voltage regulation terminal of the composite or multi-stage composite NPN transistor is connected to the resistor end of a voltage regulating resistor, which is then connected to the current-limiting power resistor connected to the emitter of the corresponding NPN transistor in the final output stage, forming the resistor terminal of the composite or multi-stage composite NPN transistor. The resistor terminal of the single NPN transistor or the resistor terminal of the composite or multi-stage composite NPN transistor forms the power supply terminal of the Class A emitter follower amplifier power amplifier circuit. The power supply terminal of the Class A NPN emitter follower amplifier power amplifier circuit is connected to ground or a negative power supply.

[0030] In this circuit, the collector of the final output stage NPN transistor in a composite or multi-stage composite NPN transistor is connected to the collector of the previous stage NPN transistor, or the collector of the final output stage NPN transistor in a composite or multi-stage composite NPN transistor is connected to the collector of the previous stage NPN transistor via a resistor, thus forming the collector of the composite or multi-stage composite NPN transistor. The collector of a single-channel or composite or multi-stage composite NPN transistor is connected to the amplified power signal output from the amplified current-limiting power resistor, forming the amplified power output terminal in the Class A NPN emitter follower power amplifier circuit. The connection point between the collector of a single-channel or composite or multi-stage composite NPN transistor and the amplified current-limiting power resistor serves as the feedback output terminal of the Class A NPN emitter follower power amplifier circuit.

[0031] Among them, the base of the input stage NPN transistor in a single, compound, or multi-stage compound NPN transistor, or the base of the input stage NPN transistor connected to the capacitor and the collector of the input stage NPN transistor, forming the connection point between the base of the input stage NPN transistor and the capacitor, is the drive signal input terminal of the Class A NPN emitter follower power amplifier circuit 4.

[0032] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, the pre-stage driver negative feedback circuit 5 includes: a phase-shifting circuit formed by a capacitor connected in series with a feedback resistor, or a feedback resistor in the pre-stage driver negative feedback circuit 5 connected in parallel with a phase-shifting capacitor, or a phase-shifting circuit formed by a feedback resistor in the pre-stage driver negative feedback circuit 5 connected in parallel with a phase-shifting capacitor and a phase-shifting resistor connected in series with a phase-shifting capacitor. The capacitor terminal or feedback resistor terminal of the pre-stage driver negative feedback circuit 5 is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit 4, and the corresponding feedback resistor terminal or capacitor terminal of the pre-stage driver negative feedback circuit 5 is connected to the feedback input terminal of the pre-stage driver circuit. In this embodiment, as shown... Figure 1, Figure 2 , Figure 3 As shown, the pre-stage drive circuit 5 consists of a capacitor C203 connected in series with a feedback resistor R206.

[0033] like Figure 1 , Figure 2 , Figure 3 As shown, in this embodiment, based on the Class A output NPN dual-transistor synchronous combining power amplifier circuit, the matching of the pre-stage PNP driver circuit 1 with the Class A NPN emitter follower output power amplifier circuit 3 and the Class A NPN emitter follower amplification power amplifier circuit 4 is as follows: the pre-stage PNP driver circuit 1 is matched and combined with the Class A NPN emitter follower output power amplifier circuit 3 and the Class A NPN emitter follower amplification power amplifier circuit 4, and connected according to the Class A output dual-transistor synchronous combining power amplifier circuit combination. Furthermore, to satisfy the emitter follower power signal output by the Class A NPN emitter follower output power amplifier circuit 3 and the amplified power signal output by the Class A NPN emitter follower amplification power amplifier circuit 4, synchronous output of the Class A combined power signal is achieved at the combining output terminal of the Class A output dual-transistor synchronous combining power amplifier circuit, thereby improving the overall circuit efficiency. Additionally, the amplified power signal extracted by the pre-stage driver negative feedback circuit is fed to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A output dual-transistor synchronous combining power amplifier circuit.

[0034] Figure 4 This invention provides an application circuit for a Class A output NPN dual-transistor synchronous combining power amplifier circuit. For example... Figure 4 As shown, a voltage amplifier circuit connected to the differential circuit is then connected to an NPN dual-transistor synchronous combining power amplifier circuit with Class A output, forming a Class A output power amplifier circuit. A resistive negative feedback circuit is connected to the negative feedback input of the differential circuit via the feedback output terminal of the combining output of the Class A output dual-transistor synchronous combining power amplifier circuit. The resistive negative feedback circuit consists of a resistor connected to resistor one via a capacitor to ground. The connection point between resistor one and resistor two is the feedback output terminal of the resistive negative feedback circuit, and one end of resistor one is the feedback input terminal, thus forming a Class A output power amplifier circuit with negative feedback.

[0035] The performance indicators of the Class A output dual-transistor synchronous combined power amplifier circuit with negative feedback when the NPN transistor current of the final stage of the composite NPN transistor in the Class A emitter follower output power amplifier circuit 3 in the Class A output dual-transistor synchronous combined power amplifier circuit is 100mA, 500mA, 1A, and 1.3A are shown in Table 1 below: Table 1 Figure 5 This document provides a schematic diagram of an audio power amplifier circuit with negative feedback, based on existing technologies. The output stage power amplifier circuit is a conventional audio power amplifier circuit. The output performance of the emitter follower output stage circuit with negative feedback, when the current is 100mA, is shown in Tables 2 (amplification gain 60dB) and 3 (amplification gain 30dB). Table 2 By comparing the data in Tables 1, 2, and 3 above, it is clear that, compared with traditional audio power amplifier circuits with negative feedback, the Class A output power amplifier circuit with negative feedback constructed using the Class A output dual-transistor synchronous combining power amplifier circuit of this invention can significantly improve the noise and distortion performance of audio power amplifier circuits.

[0036] In the Class A output dual-transistor synchronous combined power amplifier circuit, when the current of the NPN transistor corresponding to the final stage of the composite NPN transistor in the Class A emitter follower output power amplifier circuit and the NPN transistor corresponding to the final stage of the composite NPN transistor in the Class A emitter follower power amplifier circuit are 0mA, and when the Ube of the final stage NPN transistor or PNP transistor in the composite NPN transistor synchronously decreases to 0.3V, the power signal output by the synchronously combined power amplifier circuit of the Class A output dual-transistor synchronous combined power amplifier circuit has no crossover distortion. When the Ube of the final stage NPN transistor in the composite NPN transistor synchronously decreases to around 0.23V, the power signal output by the synchronously combined power amplifier circuit of the Class A output dual-transistor synchronous combined power amplifier circuit has crossover distortion. The output performance indicators in Tables 1 and 2 above are determined by the coordinated adjustment of the transistors, capacitors, resistors, PCB board, etc. in the circuit.

[0037] According to the technical solution of this invention, the DC bias voltage at the drive signal output terminal of the pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter-follower power signal output by the Class A emitter-follower power amplifier circuit and the amplified power signal output by the Class A emitter-follower power amplifier circuit to be synchronously output at the output terminal of the combining circuit, thereby improving the overall circuit efficiency. The amplified power signal extracted by the pre-stage driver negative feedback circuit through the feedback output terminal of the Class A emitter-follower power amplifier circuit is connected to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combining power amplifier circuit.

[0038] The Class A NPN or PNP emitter follower power amplifier circuit is composed of a single NPN transistor or a single PNP transistor, or by connecting the base of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor to the emitter of the corresponding stage NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding stage NPN or PNP transistor in the previous stage, an output voltage regulating terminal for the composite or multi-stage composite NPN or PNP transistor in the Class A NPN or PNP emitter follower power amplifier circuit is formed. The emitter of the final stage NPN or PNP transistor is used to form the emitter of a composite or multi-stage composite NPN or PNP transistor. The emitter of a single-channel, composite, or multi-stage composite NPN or PNP transistor is connected to the emitter follower power signal output by the current-limiting power resistor, forming the emitter follower power output terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. A voltage regulating resistor is connected to the emitter of the corresponding NPN or PNP transistor in the final stage of the composite or multi-stage composite NPN or PNP transistor, or connected to the emitter follower power output terminal of the Class A NPN or PNP emitter follower output power amplifier circuit.

[0039] The collector of the final-stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the corresponding NPN or PNP transistor in the previous stage to form the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor serves as the power supply terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. The power supply terminal of the Class A NPN emitter follower output power amplifier circuit is connected to a positive power supply, and the power supply terminal of the Class A PNP emitter follower output power amplifier circuit is connected to ground or a negative power supply.

[0040] The base of the input stage NPN or PNP transistor, whether a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor. This connection point serves as the emitter follower voltage signal input terminal for the Class A NPN or PNP emitter follower output power amplifier circuit.

[0041] Optionally, the Class A emitter follower power amplifier circuit includes: a Class A NPN or PNP emitter follower amplifier circuit composed of a single NPN transistor or a single PNP transistor, or a composite NPN transistor or a composite PNP transistor, or a multi-stage composite NPN transistor or a multi-stage composite PNP transistor and resistors.

[0042] A Class A NPN or PNP emitter follower amplifier circuit is composed of a single NPN or PNP transistor whose emitter is connected to a current-limiting power resistor; or, it is composed of a composite or multi-stage composite NPN or PNP transistor whose base is connected to the emitter of the corresponding NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding NPN or PNP transistor in the previous stage, an amplification and voltage regulation terminal for the composite or multi-stage composite NPN or PNP emitter follower power amplifier circuit is formed. The amplification and voltage regulation terminal of the PN or PNP transistor is connected to the resistance terminal of the voltage regulation resistor, and is interconnected with the resistance terminal of the current-limiting power resistor connected to the emitter of the NPN or PNP transistor corresponding to the output final stage of the composite or multi-stage composite NPN or PNP transistor, forming a resistance terminal in the composite or multi-stage composite NPN or PNP transistor; wherein, the resistance terminal of a single-channel NPN or PNP transistor or the resistance terminal of a composite or multi-stage composite NPN or PNP transistor forms the power supply terminal of the Class A emitter follower power amplifier circuit; wherein, the power supply terminal of the Class A NPN emitter follower power amplifier circuit is connected to ground or a negative power supply, and the power supply terminal of the Class A PNP emitter follower power amplifier circuit is connected to a positive power supply.

[0043] In this circuit, the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor, or the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor via a resistor, thus forming the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor is connected to the amplified power signal output from the amplified current-limiting power resistor, forming the amplified power output terminal in the Class A NPN or PNP emitter follower power amplifier circuit. The connection point between the collector of a single-channel or composite or multi-stage composite NPN or PNP transistor and the amplified current-limiting power resistor is the feedback output terminal of the Class A NPN or PNP emitter follower power amplifier circuit.

[0044] Among them, the base of the input stage NPN or PNP transistor in a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then connected to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor, which is the drive signal input terminal of the Class A NPN or PNP emitter follower power amplifier circuit.

[0045] Optionally, the pre-stage driver negative feedback circuit includes: a phase-shifting circuit formed by a capacitor connected in series with a feedback resistor, or a feedback resistor in the pre-stage driver negative feedback circuit connected in parallel with a phase-shifting capacitor, or a phase-shifting circuit formed by a feedback resistor in the pre-stage driver negative feedback circuit connected in series with a phase-shifting capacitor; the capacitor terminal or feedback resistor terminal of the pre-stage driver negative feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit, and the corresponding feedback resistor terminal or capacitor terminal of the pre-stage driver negative feedback circuit is connected to the feedback input terminal of the pre-stage driver circuit.

[0046] Optionally, the matching of the pre-amplifier PNP or NPN drive circuit with the Class A NPN or PNP emitter follower output power amplifier circuit and the Class A NPN or PNP emitter follower power amplifier circuit is as follows: The pre-stage PNP driver circuit is matched and combined with a Class A NPN emitter follower output power amplifier circuit and a Class A NPN emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Alternatively, the pre-stage NPN driver circuit is matched and combined with a Class A PNP emitter follower output power amplifier circuit and a Class A PNP emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Furthermore, the emitter follower power signal output by the Class A NPN or PNP emitter follower output power amplifier circuit and the amplified power signal output by the Class A NPN or PNP emitter follower amplification power amplifier circuit are satisfied. At the combining output terminal of the Class A output dual-transistor synchronous combining power amplifier circuit, the synchronous output of the Class A combined power signal is realized, thereby improving the efficiency of the entire circuit. In addition, the amplified power signal extracted by the pre-stage driver negative feedback circuit is sent to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A output dual-transistor synchronous combining power amplifier circuit.

[0047] Figure 6 This is a circuit diagram of another Class A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention; as shown below. Figure 6 As shown, a Class A output PNP dual-transistor synchronous combining power amplifier circuit is specifically composed of a pre-stage driver circuit 1, a load absorption circuit 12, a Class A emitter follower output power amplifier circuit 3, a Class A emitter follower amplification power amplifier circuit 4, a bias voltage circuit 7, and a power combining circuit 6.

[0048] The emitter follower voltage signal input terminal of the Class A emitter follower power amplifier circuit 3 and the pre-drive voltage signal input terminal of the pre-drive circuit 1 are directly connected to the two output terminals of the bias voltage circuit 7, respectively. The drive power signal output from the load output terminal of the pre-drive circuit 1 is connected to the absorption load circuit 12 to ground. The drive signal output from the drive signal output terminal of the pre-drive circuit 1 is connected to the drive signal input terminal of the Class A emitter follower power amplifier circuit 4. The emitter follower power signal output from the emitter follower power output terminal of the Class A emitter follower power amplifier circuit 3 and the amplified power signal output from the amplified power output terminal of the Class A emitter follower power amplifier circuit 4 are respectively connected to the two input terminals of the power combiner circuit 6. At the combined output terminal of the PNP dual-transistor synchronous combined power amplifier circuit with Class A output, the DC bias voltage at the drive signal output terminal of the pre-stage driver circuit 1, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter follower power signal output by the Class A emitter follower power amplifier circuit 3 and the amplified power signal output by the Class A emitter follower power amplifier circuit 4 to be synchronously output at the output terminal of the combined circuit, thereby improving the efficiency of the entire circuit. The amplified power signal extracted by the pre-stage driver negative feedback circuit 5 through the feedback output terminal of the Class A emitter follower power amplifier circuit 4 is connected to the feedback input terminal of the pre-stage driver circuit 1, thereby reducing the distortion signal in the synchronously output Class A combined power signal of the PNP dual-transistor synchronous combined power amplifier circuit with Class A output.

[0049] refer to Figure 6 Or, in which, the pre-stage drive circuit 1 includes: an NPN transistor 11, a resistor, a constant current source 13, and a load absorption circuit 12 forming a pre-stage NPN drive circuit. The pre-stage NPN drive circuit 1 connects the emitter of the NPN transistor 11 to ground or a negative / positive power supply, and the collector of the NPN transistor 11 is connected to a resistor to a positive power supply. The drive power signal output from the load output terminal of one branch of the connection between the emitter and the constant current source of NPN transistor 11 is connected to ground via the absorption load circuit. The second branch of the connection between the emitter and the constant current source of NPN transistor 11 is the feedback input terminal of the pre-stage NPN drive circuit 1. The connection between the collector and the resistor of NPN transistor 11 is the drive signal output terminal of the pre-stage NPN drive circuit 1. The base of NPN transistor 11 or the connection between the base of NPN transistor 11 and the capacitor connected to ground is the pre-drive voltage signal input terminal of the pre-stage NPN drive circuit 1. The pre-drive voltage signal input terminal of the pre-stage NPN drive circuit 1 is directly connected to one output terminal of the dual-output bias voltage circuit 7; or it is connected to one output terminal of the single-output bias voltage circuit 7 via the input terminal of the audio branch circuit; or it is connected to one output terminal of the dual-output bias voltage circuit.

[0050] The DC bias voltage at the connection between the collector and the resistor in the pre-amplifier NPN drive circuit meets the DC bias voltage requirements of the drive signal input terminal of the Class A emitter follower power amplifier circuit. The absorption load circuit 12 consists of a capacitor connected in series with a resistor grounded. The constant current source 13 includes a single-transistor or dual-transistor constant current source circuit, or a mirror constant current source circuit.

[0051] The bias voltage circuit 7 includes: a dual-output or single-output bias voltage circuit; the dual-output bias voltage circuit is composed of a multiplier circuit, a resistor, or a resistor in series with a diode; the single-output bias voltage circuit is composed of a single output terminal by removing the multiplier circuit, or removing the resistor, or removing the resistor in series with a diode, and short-circuiting the two output terminals.

[0052] Specifically, the DC bias voltage at the output terminal of the drive signal of the pre-stage drive circuit 1, or the voltage difference between the two output terminals of the bias voltage circuit 7, makes the base DC bias voltage of the final stage NPN or PNP transistor output by the Class A emitter follower power amplifier circuit 3 synchronously equal to or nearly equal to the base DC bias voltage of the final stage NPN and PNP transistors in the Class A emitter follower power amplifier circuit 4; at the combined output terminal of the dual-transistor synchronous combined power amplifier circuit of the Class A output, the emitter follower power signal output by the Class A emitter follower power amplifier circuit 3 and the amplified power signal output by the Class A emitter follower power amplifier circuit achieve synchronous output of the Class A combined power signal and improve the efficiency of the whole circuit. In addition, the amplified power signal extracted by the pre-stage drive negative feedback circuit 5 is sent to the feedback input terminal of the pre-stage drive circuit to reduce the distortion signal in the synchronous output Class A combined power signal of the dual-transistor synchronous combined power amplifier circuit of the Class A output.

[0053] In this embodiment, specifically, the Class A emitter follower output power amplifier circuit 3 includes: a Class A PNP emitter follower output power amplifier circuit 3 composed of a single-channel single-channel PNP transistor, or a composite PNP transistor, or a multi-stage composite PNP transistor and a resistor.

[0054] like Figure 6As shown, in this embodiment, the Class A PNP emitter follower power amplifier circuit 3 connects the base of the final output stage PNP transistor in the two-stage composite PNP transistor series to the emitter of the corresponding PNP transistor in the previous stage. At the connection point between the base of the final output stage PNP transistor and the emitter of the corresponding PNP transistor in the previous stage, the output voltage regulation terminal of the two-stage composite PNP transistors in the Class A PNP emitter follower power amplifier circuit 3 is formed. The emitter of the final output stage PNP transistor in the two-stage composite PNP transistor series forms the emitter of the two-stage composite PNP transistor series. The emitter of the two-stage composite PNP transistor series is connected to the emitter follower power signal output by the current-limiting power resistor, forming the emitter follower power output terminal of the Class A PNP emitter follower power amplifier circuit 3. A voltage regulating resistor is connected to the emitter of the corresponding PNP transistor in the final output stage of the two-stage composite PNP transistor series, or connected to the emitter follower power output terminal of the Class A PNP emitter follower power amplifier circuit 3, through the output voltage regulating terminal of the two-stage composite PNP transistor series.

[0055] The collector of the final stage PNP transistor in the two-stage composite PNP transistor is connected to the collector of the corresponding PNP transistor in the previous stage, forming the collector of the two-stage composite PNP transistor. The collector of the two-stage composite PNP transistor is the power supply terminal of the Class A PNP emitter follower output power amplifier circuit, and the power supply terminal of the Class A PNP emitter follower output power amplifier circuit 3 is connected to ground or a negative power supply.

[0056] Among them, the base of the input stage PNP transistor of the two-stage composite PNP transistor, or the base of the input stage PNP transistor connected to the collector of the input stage PNP transistor, forming the connection point between the base of the input stage PNP transistor and the capacitor, is the emitter follower voltage signal input terminal of the Class A PNP emitter follower output power amplifier circuit 3.

[0057] like Figure 6 As shown, in this embodiment, specifically, the Class A emitter follower power amplifier circuit 4 includes: a Class A PNP emitter follower amplification circuit 4 composed of two-stage composite PNP transistors and resistors; The Class A PNP emitter follower amplifier circuit 4 connects the base of the final output stage PNP transistor in the two-stage composite PNP transistor series to the emitter of the corresponding PNP transistor in the previous stage. This connection forms the amplification and voltage regulation terminal for the two-stage composite PNP transistors in the circuit 4. A voltage regulating resistor is connected to this amplification and voltage regulation terminal, which is then connected to the current-limiting power resistor connected to the emitter of the corresponding PNP transistor in the final output stage. This forms the resistance terminal of the two-stage composite PNP transistor series, which also serves as the power supply terminal for the Class A emitter follower amplifier power amplifier circuit 4. The power supply terminal of the Class A PNP emitter follower amplifier power amplifier circuit is connected to a positive power supply.

[0058] In this circuit, the collector of the final output stage PNP transistor in the two-stage composite PNP transistor is connected to the collector of the previous stage PNP transistor, or the collector of the final output stage PNP transistor in the two-stage composite PNP transistor is connected to the collector of the previous stage PNP transistor via a resistor, thus forming the collector of the two-stage composite PNP transistor. The collector of the two-stage composite PNP transistor is connected to the amplified power signal output by the amplified current-limiting power resistor, forming the amplified power output terminal in the Class A PNP emitter follower power amplifier circuit 4. The connection point between the collector of the two-stage composite PNP transistor and the amplified current-limiting power resistor is the feedback output terminal of the Class A PNP emitter follower power amplifier circuit 4.

[0059] Among them, the base of the input stage PNP transistor in the two-stage composite N PNP transistor, or the base of the input stage PNP transistor connected to the collector of the input stage PNP transistor, forming the connection point between the base of the input stage PNP transistor and the capacitor, is the drive signal input terminal of the Class A PNP emitter follower power amplifier circuit.

[0060] like Figure 6 As shown, in this embodiment, the pre-stage driver negative feedback circuit 5 is composed of a capacitor connected in series with a feedback resistor. The feedback resistor terminal of the pre-stage driver negative feedback circuit is connected to the feedback output terminal of the Class A emitter follower output power amplifier circuit 3, and the corresponding feedback resistor terminal or capacitor terminal of the pre-stage driver negative feedback circuit is connected to the feedback input terminal of the pre-stage driver circuit.

[0061] like Figure 6As shown, in this embodiment, based on the Class A output PNP dual-transistor synchronous combining power amplifier circuit, the matching of the pre-stage NPN driver circuit 1 with the Class A PNP emitter follower output power amplifier circuit 3 and the Class A PNP emitter follower amplification power amplifier circuit 4 is as follows: the pre-stage NPN driver circuit 1 is matched and combined with the Class A PNP emitter follower output power amplifier circuit 3 and the Class A PNP emitter follower amplification power amplifier circuit 4, and connected according to the Class A output dual-transistor synchronous combining power amplifier circuit combination. Furthermore, to satisfy the emitter follower power signal output by the Class A PNP emitter follower output power amplifier circuit 3 and the amplified power signal output by the Class A PNP emitter follower amplification power amplifier circuit 4, synchronous output of the Class A combined power signal is achieved at the combining output terminal of the Class A output dual-transistor synchronous combining power amplifier circuit, thereby improving the overall circuit efficiency. Additionally, the amplified power signal extracted by the pre-stage driver negative feedback circuit 5 is fed to the feedback input terminal of the pre-stage driver circuit 1, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A output dual-transistor synchronous combining power amplifier circuit.

[0062] Figure 7 This is a circuit diagram of another Class A output dual-transistor synchronous combining power amplifier circuit provided in an embodiment of the present invention. (See diagram below.) Figure 7 As shown, in any embodiment of the present invention, an NPN dual-transistor synchronous combining power amplifier circuit with Class A output is described. Figure 1Based on the circuit structure diagram shown, the voltage regulating resistors connected to the voltage regulating terminals of the two-stage composite NPN transistors in the Class A emitter follower power amplifier circuit 4 are removed. Instead, the base of the constant current controlled NPN transistor is connected to the connection point between the emitter of the corresponding NPN transistor and the current limiting power resistor in the Class A emitter follower power amplifier circuit 4. The emitter of the constant current controlled NPN transistor 13 is connected to the power supply terminal of the Class A emitter follower power amplifier circuit 4, forming the modified power supply terminal of the Class A emitter follower power amplifier circuit 4. In this modified circuit, the collector of the constant current-controlled NPN transistor 13 is connected to the base of the NPN transistor corresponding to the final stage of the two-stage composite NPN transistor output in the Class A emitter follower power amplifier circuit, and the emitter of the corresponding NPN transistor in the previous stage is connected to the base of the single-channel, composite, or multi-stage composite NPN transistor output in the Class A emitter follower power amplifier circuit. The connection is then made via a control resistor to the positive power supply, ground, or negative power supply, and via the control resistor to the midpoint voltage connection of the added voltage divider resistor, thus forming the modified Class A emitter follower power amplifier circuit. The constant current source circuit and absorption load circuit in the pre-stage driver circuit are removed, and the capacitor in the pre-stage driver feedback circuit is removed. Instead, the feedback resistor in the pre-stage driver feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit. Alternatively, at the connection point between the emitter and feedback resistor in the pre-stage driver circuit, an additional emitter resistor is connected to the midpoint voltage connection point of the additional voltage divider circuit. This forms the modified pre-stage driver circuit and the modified pre-stage driver feedback circuit. The emitter voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-driver voltage signal input terminal of the modified pre-stage driver circuit can only be connected to the two output terminals of the two-channel output bias voltage circuits, respectively. This forms a Class A output single-transistor synchronous constant current power amplifier circuit.

[0063] At the combined output terminal of the single-transistor synchronous combined power amplifier circuit with Class A output, the DC bias voltage at the drive signal output terminal of the pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the modified Class A emitter follower power amplifier circuit to be synchronously output at the output terminal of the combined circuit, thereby improving the efficiency of the entire circuit. Furthermore, the amplified power signal extracted by the pre-stage driver negative feedback circuit is fed to the feedback input terminal of the pre-stage driver circuit to reduce the distortion signal in the synchronously output Class A combined power signal of the single-transistor synchronous combined power amplifier circuit with Class A output.

[0064] Figure 8 A circuit diagram of another Class A output dual-transistor synchronous combining power amplifier circuit provided in this embodiment of the invention is shown below. Figure 8As shown, based on the Class A output PNP dual-transistor synchronous combining power amplifier circuit in any embodiment of the present invention, the voltage regulating resistors connected to the voltage regulating terminals of the two-stage composite PNP transistors in the Class A emitter follower power amplifier circuit 4 are removed. Instead, the base of the constant current controlled PNP transistor 13 is connected to the connection point between the emitter of the corresponding PNP transistor in the two-stage composite PNP transistors of the Class A emitter follower power amplifier circuit 4 and the current-limiting power resistor. The emitter of the constant current controlled PNP transistor 13 is then connected to the power supply terminal of the Class A emitter follower power amplifier circuit 4, forming the modified power supply terminal of the Class A emitter follower power amplifier circuit 4. Furthermore, the collector of the constant current controlled PNP transistor 13 is connected to the connection point between the base of the PNP transistor corresponding to the final output stage of the two-stage composite PNP transistors in the Class A emitter follower power amplifier circuit 4 and the emitter of the corresponding PNP transistor in the previous stage. Alternatively, the collector of the constant current-controlled PNP transistor 13 can be connected to the base of the corresponding PNP transistor in the last stage of the two-stage composite PNP transistor output of the Class A emitter follower power amplifier circuit 4, and the emitter of the corresponding PNP transistor in the previous stage can be connected to the positive power supply, ground, or negative power supply via a control resistor. The control resistor can also be connected to the midpoint voltage connection of the added voltage divider resistor, thus forming a modified Class A emitter follower power amplifier circuit 4. The constant current source circuit and the absorption load circuit 12 in the pre-stage drive circuit 1 can be removed, and the capacitor in the pre-stage drive feedback circuit can be removed. Instead, the feedback resistor in the pre-stage drive feedback circuit can be connected to the feedback output terminal of the Class A emitter follower power amplifier circuit 4. Alternatively, at the connection point between the emitter and feedback resistor in the pre-stage drive circuit, an added emitter resistor can be connected to the midpoint voltage connection of the added voltage divider resistor circuit, thus forming a modified pre-stage drive circuit and a modified pre-stage drive feedback circuit. In this circuit, the emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-driver voltage signal input terminal of the modified pre-stage driver circuit can only be connected to the two output terminals of the two-output bias voltage circuits, respectively. This forms a Class A output single-transistor synchronous constant current power amplifier circuit. At the combined output terminal of the single-transistor synchronous combined power amplifier circuit with Class A output, the DC bias voltage at the drive signal output terminal of the pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the modified Class A emitter follower power amplifier circuit to be synchronously output at the output terminal of the combined circuit, thereby improving the efficiency of the entire circuit. Furthermore, the amplified power signal extracted by the pre-stage driver negative feedback circuit is fed to the feedback input terminal of the pre-stage driver circuit to reduce the distortion signal in the synchronously output Class A combined power signal of the single-transistor synchronous combined power amplifier circuit with Class A output.

[0065] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0066] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A dual-transistor synchronous combining power amplifier circuit with Class A output, characterized in that, include: Preamplifier driver circuit, load absorption circuit, Class A emitter follower output power amplifier circuit, Class A emitter follower power amplifier circuit, preamplifier driver negative feedback circuit, audio branch circuit, bias voltage circuit, power combiner circuit. Among them, the emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-drive voltage signal input terminal of the pre-drive circuit are respectively connected to the two output terminals of the audio splitter circuit, and connected to one output terminal of the bias voltage circuit through the input terminal of the audio splitter circuit. Alternatively, the input terminals of the follower voltage signal and the input terminals of the preceding voltage signal can be directly connected to the two output terminals of the bias voltage circuit respectively. The drive power signal output from the load output terminal of the pre-amplifier driver circuit is connected to the load absorption circuit to ground; the drive signal output from the drive signal output terminal of the pre-amplifier driver circuit is connected to the drive signal input terminal of the Class A emitter follower power amplifier circuit. The emitter-follower power signal output from the emitter-follower power amplifier circuit and the amplified power signal output from the amplified power amplifier circuit are respectively connected to the two input terminals of the power combiner circuit. At the combined output terminal of the dual-transistor synchronous combined power amplifier circuit, the DC bias voltage of the drive signal output terminal of the pre-stage drive circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter-follower power signal output from the class-A emitter-follower power amplifier circuit and the amplified power signal output from the class-A emitter-follower power amplifier circuit to be synchronously output at the output terminal of the combiner circuit, thereby improving the overall circuit efficiency. The amplified power signal extracted by the pre-stage driver negative feedback circuit through the feedback output terminal of the Class A emitter follower power amplifier circuit is connected to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A dual-transistor synchronous combined power amplifier circuit.

2. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, The pre-stage drive circuit includes: a PNP or NPN transistor, a resistor, a constant current source, and a load absorption circuit, forming a pre-stage PNP or NPN drive circuit. The pre-stage PNP driver circuit connects the emitter of the PNP transistor to a constant current source connected to the positive power supply, and the collector of the PNP transistor is connected to a resistor connected to ground or to the negative power supply. The drive power signal output from the load output terminal of one branch of the connection between the emitter of the PNP transistor and the constant current source is connected to ground via a load absorption circuit. The other branch of the connection between the emitter of the PNP transistor and the constant current source serves as the feedback input terminal of the pre-stage PNP driver circuit. The connection between the collector of the PNP transistor and the resistor serves as the drive signal output terminal of the pre-stage PNP driver circuit. The base of the PNP transistor or the connection between the base of the PNP transistor and the capacitor connected to ground serves as the pre-driver voltage signal input terminal of the pre-stage PNP driver circuit. The pre-driver voltage signal input terminal of the pre-stage PNP driver circuit is directly connected to one output terminal of the dual-output bias voltage circuit, or it can be connected to one output terminal of the single-output bias voltage circuit or one output terminal of the dual-output bias voltage circuit via one output terminal of the connected audio branch circuit. In one configuration, the pre-stage NPN driver circuit connects the emitter of the NPN transistor to a constant current source connected to ground or a negative / positive power supply, and the collector of the NPN transistor connected to a resistor connected to a positive power supply. The drive power signal output from the load output terminal of one branch at the connection between the NPN transistor's emitter and the constant current source is connected to ground via a load absorption circuit. The other branch at the connection between the NPN transistor's emitter and the constant current source serves as the feedback input terminal of the pre-stage NPN driver circuit. The connection between the NPN transistor's collector and the resistor serves as the drive signal output terminal of the pre-stage NPN driver circuit. The base of the NPN transistor, or the base of the NPN transistor connected to a capacitor connected to ground, or the connection between the base of the power supply and the capacitor, serves as the pre-driver voltage signal input terminal of the pre-stage NPN driver circuit. The pre-driver voltage signal input terminal of the pre-stage NPN driver circuit can be directly connected to one output terminal of a dual-output bias voltage circuit; or, through one output terminal of a connected audio branch circuit, and via the input terminal of the audio branch circuit, it can be connected to a single output terminal of a single-output bias voltage circuit; or it can be connected to one output terminal of a dual-output bias voltage circuit. Among them, the DC bias voltage at the connection between the collector and the resistor in the front-end PNP or NPN drive circuit meets the DC bias voltage requirements of the drive signal input terminal of the Class A emitter follower power amplifier circuit. The audio splitter circuit consists of a circuit that is split into two. The load absorption circuit consists of a capacitor connected in series with a resistor and grounded. The constant current source includes a single-transistor or dual-transistor constant current source circuit, or a mirror constant current source circuit; The bias voltage circuit includes: a dual-output or single-output bias voltage circuit; the dual-output bias voltage circuit is composed of a multiplier circuit, or a resistor, or a resistor in series with a diode; the single-output bias voltage circuit is composed of removing the multiplier circuit, or removing the resistor, or removing the resistor in series with a diode, and short-circuiting the two output terminals to form a single output terminal. Specifically, by using the DC bias voltage at the output terminal of the drive signal of the pre-stage drive circuit, or by using the voltage difference between the two output terminals of the bias voltage circuit, the DC bias voltage of the base of the final NPN or PNP transistor in the Class A emitter follower power amplifier circuit is made synchronously equal to or nearly equal to the DC bias voltage of the base of the final NPN or PNP transistor in the Class A emitter follower power amplifier circuit. At the combined output terminal of the dual-transistor synchronous combined power amplifier circuit, the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the Class A emitter follower power amplifier circuit are synchronously output to achieve a Class A combined power signal and improve the overall circuit efficiency. Furthermore, the amplified power signal extracted by the pre-stage drive negative feedback circuit is fed to the feedback input terminal of the pre-stage drive circuit, thereby reducing the distortion signal in the synchronously output Class A combined power signal of the dual-transistor synchronous combined power amplifier circuit.

3. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, in, Class A emitter follower output power amplifier circuit includes: a Class A NPN or PNP emitter follower output power amplifier circuit composed of a single NPN transistor or a single PNP transistor, or a composite NPN transistor or a composite PNP transistor, or a multi-stage composite NPN transistor or a multi-stage composite PNP transistor and resistors. The Class A NPN or PNP emitter follower power amplifier circuit is composed of a single NPN transistor or a single PNP transistor, or by connecting the base of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor to the emitter of the corresponding stage NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding stage NPN or PNP transistor in the previous stage, an output voltage regulating terminal for the composite or multi-stage composite NPN or PNP transistor in the Class A NPN or PNP emitter follower power amplifier circuit is formed. The emitter of the final stage NPN or PNP transistor is used to form the emitter of a composite or multi-stage composite NPN or PNP transistor. The emitter of a single-channel, composite, or multi-stage composite NPN or PNP transistor is connected to the emitter follower power signal output by the current-limiting power resistor, forming the emitter follower power output terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. A voltage regulating resistor is connected to the emitter of the corresponding NPN or PNP transistor in the final stage of the composite or multi-stage composite NPN or PNP transistor, or connected to the emitter follower power output terminal of the Class A NPN or PNP emitter follower output power amplifier circuit. The collector of the final-stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the corresponding NPN or PNP transistor in the previous stage to form the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor is the power supply terminal of a Class A NPN or PNP emitter follower output power amplifier circuit. The power supply terminal of the Class A NPN emitter follower output power amplifier circuit is connected to a positive power supply, and the power supply terminal of the Class A PNP emitter follower output power amplifier circuit is connected to ground or a negative power supply. The base of the input stage NPN or PNP transistor, whether a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor. This connection point serves as the emitter follower voltage signal input terminal for the Class A NPN or PNP emitter follower output power amplifier circuit.

4. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, in, Class A emitter follower power amplifier circuits include: Class A NPN or PNP emitter follower amplifier circuits composed of a single NPN transistor or a single PNP transistor, or a composite NPN transistor or a composite PNP transistor, or a multi-stage composite NPN transistor or a multi-stage composite PNP transistor and resistors. A Class A NPN or PNP emitter follower amplifier circuit is composed of a single NPN or PNP transistor whose emitter is connected to a current-limiting power resistor; or, it is composed of a composite or multi-stage composite NPN or PNP transistor whose base is connected to the emitter of the corresponding NPN or PNP transistor in the previous stage. At the connection point between the base of the final output stage NPN or PNP transistor and the emitter of the corresponding NPN or PNP transistor in the previous stage, an amplification and voltage regulation terminal for the composite or multi-stage composite NPN or PNP emitter follower power amplifier circuit is formed. The amplification and voltage regulation terminal of the PN or PNP transistor is connected to the resistance terminal of the voltage regulation resistor, and is interconnected with the resistance terminal of the current-limiting power resistor connected to the emitter of the NPN or PNP transistor corresponding to the output final stage of the composite or multi-stage composite NPN or PNP transistor, forming a resistance terminal in the composite or multi-stage composite NPN or PNP transistor; wherein, the resistance terminal of a single-channel NPN or PNP transistor or the resistance terminal of a composite or multi-stage composite NPN or PNP transistor forms the power supply terminal of the Class A emitter follower power amplifier circuit; wherein, the power supply terminal of the Class A NPN emitter follower power amplifier circuit is connected to ground or a negative power supply, and the power supply terminal of the Class A PNP emitter follower power amplifier circuit is connected to a positive power supply. In this circuit, the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor, or the collector of the final output stage NPN or PNP transistor in a composite or multi-stage composite NPN or PNP transistor is connected to the collector of the previous stage NPN or PNP transistor via a resistor, thus forming the collector of the composite or multi-stage composite NPN or PNP transistor. The collector of a single-channel or composite or multi-stage composite NPN or PNP transistor is connected to the amplified power signal output from the amplified current-limiting power resistor, forming the amplified power output terminal in the Class A NPN or PNP emitter follower power amplifier circuit. The connection point between the collector of a single-channel or composite or multi-stage composite NPN or PNP transistor and the amplified current-limiting power resistor is the feedback output terminal of the Class A NPN or PNP emitter follower power amplifier circuit. Among them, the base of the input stage NPN or PNP transistor in a single, composite, or multi-stage composite NPN or PNP transistor, or the base of the input stage NPN or PNP transistor connected to a capacitor and then connected to the collector of the input stage NPN or PNP transistor, forms the connection point between the base of the input stage NPN or PNP transistor and the capacitor, which is the drive signal input terminal of the Class A NPN or PNP emitter follower power amplifier circuit.

5. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, in, The pre-amplifier negative feedback circuit includes: a phase-shifting circuit formed by a capacitor connected in series with a feedback resistor, or a feedback resistor and a phase-shifting capacitor connected in parallel in the pre-amplifier negative feedback circuit, or a phase-shifting circuit formed by a feedback resistor, a phase-shifting resistor, and a phase-shifting capacitor connected in series in the pre-amplifier negative feedback circuit; the capacitor terminal or feedback resistor terminal of the pre-amplifier negative feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit, and the corresponding feedback resistor terminal or capacitor terminal of the pre-amplifier negative feedback circuit is connected to the feedback input terminal of the pre-amplifier drive circuit.

6. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, The matching of the pre-amplifier PNP or NPN drive circuit with the Class A NPN or PNP emitter follower output power amplifier circuit and the Class A NPN or PNP emitter follower power amplifier circuit is as follows: The pre-stage PNP driver circuit is matched and combined with a Class A NPN emitter follower output power amplifier circuit and a Class A NPN emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Alternatively, the pre-stage NPN driver circuit is matched and combined with a Class A PNP emitter follower output power amplifier circuit and a Class A PNP emitter follower amplification power amplifier circuit, and connected in accordance with the Class A output dual-transistor synchronous combining power amplifier circuit combination. Furthermore, the emitter follower power signal output by the Class A NPN or PNP emitter follower output power amplifier circuit and the amplified power signal output by the Class A NPN or PNP emitter follower amplification power amplifier circuit are satisfied. At the combining output terminal of the Class A output dual-transistor synchronous combining power amplifier circuit, the synchronous output of the Class A combined power signal is realized, thereby improving the efficiency of the entire circuit. In addition, the amplified power signal extracted by the pre-stage driver negative feedback circuit is sent to the feedback input terminal of the pre-stage driver circuit, thereby reducing the distortion signal in the Class A combined power signal synchronously output by the Class A output dual-transistor synchronous combining power amplifier circuit.

7. The dual-transistor synchronous combining power amplifier circuit with Class A output according to claim 1, characterized in that, Based on the Class A output dual-transistor synchronous combined power amplifier circuit, the voltage regulating resistor connected to the voltage regulating terminal of the composite or multi-stage composite NPN or PNP transistor in the Class A emitter follower power amplifier circuit is removed. Instead, the base of the constant current controlled NPN or PNP transistor is connected to the connection point between the emitter of the corresponding NPN or PNP transistor in the Class A emitter follower power amplifier circuit and the current limiting power resistor. The emitter of the constant current controlled NPN or PNP transistor is then connected to the power supply terminal of the Class A emitter follower power amplifier circuit, forming the modified power supply terminal of the Class A emitter follower power amplifier circuit. Furthermore, the collector of the constant current controlled NPN or PNP transistor is connected to the connection point between the base of the corresponding NPN or PNP transistor in the final stage of the single-stage or multi-stage composite NPN or PNP transistor output in the Class A emitter follower power amplifier circuit and the emitter of the corresponding NPN or PNP transistor in the previous stage. Alternatively, the collector connection of the constant current-controlled NPN or PNP transistor in the Class A emitter follower power amplifier circuit can be modified. The base of the corresponding NPN or PNP transistor in the final stage of the output circuit can be connected to the emitter of the corresponding NPN or PNP transistor in the previous stage via a control resistor, which is then connected to the positive power supply, ground, or negative power supply. The control resistor is then connected to the midpoint voltage connection of an added voltage divider resistor, forming the modified Class A emitter follower power amplifier circuit. The constant current source circuit and absorption load circuit in the pre-stage driver circuit are removed, as are the capacitors in the pre-stage driver feedback circuit. The feedback resistor in the pre-stage driver feedback circuit is connected to the feedback output terminal of the Class A emitter follower power amplifier circuit, or an additional emitter resistor is connected to the midpoint voltage connection of the additional voltage divider circuit at the connection point between the emitter and the feedback resistor in the pre-stage driver circuit, forming the modified pre-stage driver circuit and the modified pre-stage driver feedback circuit; wherein, the emitter follower voltage signal input terminal of the Class A emitter follower output power amplifier circuit and the pre-drive voltage signal input terminal of the modified pre-stage driver circuit can only be connected to the two output terminals of the two-way output bias voltage circuit respectively, forming a Class A output single-tube synchronous constant current power amplifier circuit; At the combined output terminal of the single-transistor synchronous constant current power amplifier circuit with Class A output, the DC bias voltage at the drive signal output terminal of the modified pre-stage driver circuit, or the voltage difference between the two output terminals of the bias voltage circuit, enables the emitter follower power signal output by the Class A emitter follower power amplifier circuit and the amplified power signal output by the modified Class A emitter follower power amplifier circuit to be synchronously output at the output terminal of the combined circuit, thereby improving the efficiency of the entire circuit. Furthermore, the amplified power signal extracted by the pre-stage driver negative feedback circuit is fed to the feedback input terminal of the pre-stage driver circuit to reduce the distortion signal in the synchronously output Class A combined power signal of the single-transistor synchronous constant current power amplifier circuit with Class A output.

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