Audio power tube circuit

Abstract

The invention discloses an audio power tube circuit which comprises a controllable voltage stabilization source module, a constant current bias module and a current expansion module, the controllable voltage stabilization source module, the constant current bias module and the current expansion module are connected with one another, and the current expansion module is connected with an audio power tube; the constant current bias module comprises an MOS tube and a protection resistor. The current expanding module comprises a constant current triode and a variable current circuit; the grid electrode of the MOS tube is connected with the base electrode of the constant-current triode, and the emitting electrode of the constant-current triode is connected with one end of the variable-current circuit; the other end of the variable current circuit is connected with the controllable stabilized voltage source module; a collector electrode of the constant current triode is connected with a drain electrode of the MOS tube and an anode of an external power supply, a source electrode of the MOS tube is connected with one end of the protection resistor, and the other end of the protection resistor is connected with one end of the controllable voltage stabilization source circuit and a base electrode of the constant current triode. The purposes of providing adjustable constant current for the audio power tube and protecting the audio power tube are achieved, and the application range of the audio power tube is widened.

Description

Technical Field

[0001] This application relates to the technical field of power amplifier circuits, and particularly to an audio power transistor circuit. Background Art

[0002] With the continuous progress of technology and the continuous expansion of application scenarios, audio power triodes (usually also called audio power transistors) are widely used in products such as car audio and digital home appliances to amplify the power of audio signals. In order to improve linearity, reduce audio distortion, and enhance stability, relevant protection circuits need to be set for audio power triodes.

[0003] In view of this, this application is specifically proposed. Summary of the Invention

[0004] The following gives a brief overview of one or more aspects to provide a basic understanding of these aspects. This overview is not an exhaustive survey of all contemplated aspects, and is neither intended to identify key or decisive elements of all aspects nor to define the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description to follow.

[0005] This application provides an audio power transistor circuit, which realizes the purpose of providing an adjustable constant current for the audio power transistor and protecting the audio power transistor, broadens the usage range of the audio power transistor, and ensures the working performance of the audio power transistor.

[0006] In a first aspect, this application provides an audio power transistor circuit, including a controllable voltage regulator module, a constant current biasing module, and a current expansion module. The controllable voltage regulator module, the constant current biasing module, and the current expansion module are connected to each other, and the current expansion module is connected to an audio power transistor;

[0007] Among them, the constant current biasing module includes a MOS transistor and a protection resistor; the current expansion module includes a constant current triode and a variable current circuit;

[0008] The gate of the MOS transistor is connected to the base of the constant current triode, the emitter of the constant current triode is connected to one end of the variable current circuit; the other end of the variable current circuit is connected to the controllable voltage regulator module; the collector of the constant current triode is connected to the drain of the MOS transistor and the positive pole of the external power supply, the source of the MOS transistor is connected to one end of the protection resistor, and the other end of the protection resistor is connected to one end of the controllable voltage regulator circuit and the base of the constant current triode.

[0009] Further, the variable current circuit includes a rheostat, one end of the rheostat is connected to the emitter of the constant current triode, and the other end of the rheostat is connected to the controllable voltage regulator module.

[0010] Further, it further includes: an overcurrent protection module, and the overcurrent protection module is connected to the audio power tube.

[0011] Further, the overcurrent protection module includes: an overcurrent protection triode and an overcurrent protection resistor;

[0012] Wherein, the base of the overcurrent protection triode is connected to the emitter of the audio power tube and one end of the overcurrent protection resistor, the collector of the overcurrent protection triode is connected to the base of the audio power tube, and the emitter of the overcurrent protection triode is connected to the other end of the overcurrent protection resistor.

[0013] Further, the controllable regulated power supply module includes: a first drive circuit, a second drive circuit, a first Darlington circuit, a second Darlington circuit, a second triode, a fifth triode, and a ninth triode;

[0014] Wherein, the emitter of the second triode is connected to the emitter of the first Darlington circuit and the constant current triode; the base of the second triode is connected to the collector of the second triode; the collector of the second triode is connected to the first drive circuit; the first drive circuit is further connected to the first Darlington circuit; the first Darlington circuit is further connected to the second drive circuit; the emitter of the fifth triode is connected to the first Darlington circuit; the base of the fifth triode is connected to the second drive circuit; the second drive circuit is further connected to the base of the ninth triode; the emitter of the fifth triode is connected to the emitter of the ninth triode; the collector of the ninth triode is connected to the first drive circuit and the second Darlington circuit; the second Darlington circuit is connected to the first drive circuit.

[0015] Further, the first Darlington circuit includes a first triode and a sixth triode; the second drive circuit includes a third triode, a fourth triode, a first resistor, a second resistor, a third resistor, and a fourth resistor;

[0016] The collector of the first triode is respectively connected to the second Darlington circuit and the first drive circuit; the emitter of the first triode is connected to one end of the first resistor and the base of the sixth triode; the base of the first triode is connected to the emitter of the second triode; the other end of the first resistor is respectively connected to one end of the second resistor and one end of the third resistor; the other end of the second resistor is connected to the collector and the base of the third triode; the emitter of the third triode is connected to one end of the fourth resistor, the emitter of the fifth triode, the emitter of the ninth triode and the second Darlington circuit, and is simultaneously connected to the zero potential terminal; the base of the third triode is connected to the base of the fourth triode; the emitter of the fourth triode is connected to the other end of the fourth resistor; the collector of the fourth triode is connected to the other end of the third resistor and the base of the fifth triode; the collector of the fifth triode is connected to one end of the sixth resistor; the other end of the sixth resistor is connected to the emitter of the sixth triode; the collector of the sixth triode is connected to the first drive circuit.

[0017] Further, the second Darlington circuit includes a thirteenth triode, an eleventh triode, a ninth resistor and a tenth resistor; the first drive circuit includes a seventh triode, an eighth triode, a fifth resistor and an eighth resistor;

[0018] The collector of the sixth triode is respectively connected to the collector and the base of the seventh triode; the emitter of the seventh triode is connected to one end of the fifth resistor; the base of the seventh triode is connected to the base of the eighth triode; the collector of the eighth triode is connected to the collector of the second triode and the collector of the ninth triode; the emitter of the eighth triode is connected to one end of the eighth resistor; the other ends of the fifth resistor and the eighth resistor are simultaneously connected to the collector of the first triode;

[0019] The emitter of the thirteenth triode is connected to one end of the ninth resistor; the other end of the ninth resistor is respectively connected to the base of the eleventh triode and one end of the tenth resistor; the other end of the tenth resistor is connected to the emitter of the eleventh triode; the emitter of the eleventh triode is connected to the zero potential terminal; the base of the thirteenth triode is connected to the collector of the eighth triode and is connected to the collector of the ninth triode; the collector of the thirteenth triode and the collector of the eleventh triode are simultaneously connected to the collector of the first triode and the other end of the protection resistor.

[0020] Further, a first capacitor is provided between the base and the collector of the fifth triode; a seventh resistor is provided between the base of the ninth triode and the base of the third triode; a second capacitor is provided between the base of the thirteenth triode and the eighth resistor; the base of the thirteenth triode is connected to the negative electrode of a first diode; the positive electrode of the first diode is connected to the zero potential terminal; the other end of the protection resistor is connected to the negative electrode of a second diode; the positive electrode of the second diode is connected to the zero potential terminal.

[0021] Further, the seventh triode and the eighth triode are PNP type triodes; the first triode, the second triode, the third triode, the fourth triode, the fifth triode, the sixth triode, the ninth triode, the thirteenth triode and the eleventh triode are all NPN type triodes.

[0022] Further, the base current of the audio power tube is determined by the resistance value of the rheostat.

[0023] The audio power tube circuit disclosed in this application, by providing a controllable voltage stabilizing source module, a constant current biasing module and a current boosting module, and the current boosting module includes a constant current triode and a variable current circuit, realizes the purpose of providing an adjustable constant current for the audio power tube and protecting the audio power tube, broadens the use range of the audio power tube, and ensures the working performance of the audio power tube. Description of the Drawings

[0024] In order to more clearly illustrate the technical solutions of the embodiments of this application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of this application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings.

[0025] Figure 1 Schematic diagram of an audio power tube circuit provided by an embodiment of this application Figure 1 ;

[0026] Figure 2 Schematic diagram of an audio power tube circuit provided by an embodiment of this application Figure 2 ;

[0027] Figure 3 Schematic diagram of an audio power tube circuit provided by an embodiment of this application Figure 3 ;

[0028] Figure 4 Schematic diagram of an audio power tube circuit provided by an embodiment of this application Figure 4 。 Detailed Embodiments

[0029] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. It can be understood that the specific embodiments described herein are only for explaining the related invention and not for limiting the invention. Additionally, it should be noted that for the sake of description, only the parts related to the invention are shown in the drawings.

[0030] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. The present application will be described in detail below with reference to the drawings and embodiments.

[0031] In some embodiments, Figure 1 As shown in the schematic diagram of an audio power tube circuit, the audio power tube circuit includes an audio power tube BG2 and a bias module 110. The function of the bias module 110 is to provide a constant current value for the audio power tube BG2, thereby protecting the audio power tube BG2 and ensuring its working performance. The constant current value provided by the bias module 110 can be determined by the chip manufacturing process and can be artificially controlled. Assuming that the constant current value provided by the chip manufacturing process is 0.3 mA, then according to the electronic circuit theory: the collector current Ic of the audio power tube BG2 = 0.3 x the amplification factor of BG2 (the amplification factor of BG2 is usually controlled between 50 and 100), then Ic is approximately 15 mA to 30 mA, which is equivalent to adding a bias internally. Since the base current of the audio power tube BG1 is constant (0.3 mA), the collector current Ic is also constant and is independent of the working voltage, thereby ensuring the current consistency of the audio power tube BG2, protecting the audio power tube BG2, and ensuring its working performance.

[0032] Furthermore, in some embodiments, Figure 2 As shown in the schematic diagram of an audio power tube circuit, the audio power tube circuit includes an audio power tube BG2, a bias module 110, and an overcurrent protection module. The overcurrent protection module is used to protect the audio power tube BG2 from being damaged by a large current. As Figure 2 shown, the overcurrent protection module specifically includes: an overcurrent protection triode BG3 and an overcurrent protection resistor Re; wherein, the base of the overcurrent protection triode BG3 is connected to the emitter of the audio power tube BG2 and one end of the overcurrent protection resistor Re, the collector of the overcurrent protection triode BG3 is connected to the base of the audio power tube BG2, and the emitter of the overcurrent protection triode BG3 is connected to the other end of the overcurrent protection resistor Re.

[0033] Function of overcurrent protection resistor Re: Assume that the overcurrent protection resistor Re is a resistor equivalent to 0.25 Ω. When the current flowing through it is its rated current (note: its rated current can be artificially controlled through the chip manufacturing process, assumed to be 2 A), when the current flowing through it is less than 2 A, its equivalent resistance is 0.25 Ω. When the current flowing through it is greater than 2 A, its voltage drop is greater than 0.5 V, which causes the overcurrent protection triode BG3 to tend to saturate and conduct, making the CE terminals (i.e., the collector and emitter) of the overcurrent protection triode BG3 short-circuited, thereby forcing the audio power triode BG2 to cut off, achieving the purpose of protecting the safety of the audio power triode BG2.

[0034] Further, in some embodiments, the bias module 110 includes a controllable voltage regulator module, a constant current bias module, and a current expansion module. The controllable voltage regulator module, the constant current bias module, and the current expansion module are connected to each other, and the current expansion module is connected to the audio power triode. The constant current bias module includes a MOS transistor and a protection resistor; the current expansion module includes a constant current triode and a variable current circuit. Specifically, the controllable voltage regulator module is used to provide a stable required voltage for the constant current bias module and the current expansion module. The constant current bias module is used to provide a constant current for the audio power triode BG2. The current expansion module is used to adjust the magnitude of the constant current, thereby realizing precise adjustment of the variable constant current, greatly broadening the usability of the audio power triode. The audio power triode circuit is packaged through a process, which can reduce the complexity of the peripheral circuit, improve the overall stability of the circuit, and the convenience for audio power amplifier developers.

[0035] In some embodiments, referring to the optional implementation circuit structure of the bias module 110 as Figure 3 shown, the gate of the MOS transistor G is connected to the base of the constant current triode BG1, the emitter of the constant current triode BG1 is connected to one end of the variable current circuit; the other end of the variable current circuit is connected to the controllable voltage regulator module; the collector of the constant current triode BG1 is connected to the drain of the MOS transistor and the positive pole of the external power supply, the source of the MOS transistor is connected to one end of the protection resistor Rs, and the other end of the protection resistor Rs is connected to one end of the controllable voltage regulator circuit and the base of the constant current triode BG1.

[0036] The variable current circuit includes a variable resistor RL. One end of the variable resistor RL is connected to the emitter of the constant current triode BG1, and the other end of the variable resistor RL is connected to the controllable voltage regulator module.

[0037] The controllable voltage regulator module includes: a first drive circuit, a second drive circuit, a first Darlington circuit, a second Darlington circuit, a second triode V2, a fifth triode V5, and a ninth triode V9;

[0038] Among them, the emitter of the second triode V2 is connected to the emitter of the first Darlington circuit and the constant current triode BG1 (i.e., Figure 3 A1 and A1' in

[0039] are connected); the base of the second triode V2 is connected to the collector of the second triode V2; the collector of the second triode V2 is connected to the first drive circuit; the first drive circuit is also connected to the first Darlington circuit; the first Darlington circuit is also connected to the second drive circuit; the emitter of the fifth triode V5 is connected to the first Darlington circuit; the base of the fifth triode V5 is connected to the second drive circuit; the second drive circuit is also connected to the base of the ninth triode V9; the emitter of the fifth triode V5 is connected to the emitter of the ninth triode V9; the collector of the ninth triode V9 is connected to the first drive circuit and the second Darlington circuit; the second Darlington circuit is connected to the first drive circuit.

[0040] Specifically, the first Darlington circuit includes a first triode V1 and a sixth triode V6; the second drive circuit includes a third triode V3, a fourth triode V4, a first resistor R1, a second resistor R2, a third resistor R3, and a fourth resistor R4.

[0041] The second Darlington circuit includes a thirteenth triode V10, an eleventh triode V11, a ninth resistor R9, and a tenth resistor R10; the first drive circuit includes a seventh triode V7, an eighth triode V8, a fifth resistor R5, and an eighth resistor R8. The collector of the sixth triode V6 is respectively connected to the collector and the base of the seventh triode V7; the emitter of the seventh triode V7 is connected to one end of the fifth resistor R5; the base of the seventh triode V7 is connected to the base of the eighth triode V8; the collector of the eighth triode V8 is connected to the collector of the second triode V2 and the collector of the ninth triode V9; the emitter of the eighth triode V8 is connected to one end of the eighth resistor R8; the other ends of the fifth resistor R5 and the eighth resistor R8 are simultaneously connected to the collector of the first triode V1.

[0042] The emitter of the thirteenth triode V10 is connected to one end of the ninth resistor R9; the other end of the ninth resistor R9 is respectively connected to the base of the eleventh triode V11 and one end of the tenth resistor R10; the other end of the tenth resistor R10 is connected to the emitter of the eleventh triode V11; the emitter of the eleventh triode V11 is connected to the zero potential terminal; the base of the thirteenth triode V10 is connected to the collector of the eighth triode V8 and is connected to the collector of the ninth triode V9; the collectors of the thirteenth triode V10 and the eleventh triode V11 are simultaneously connected to the collector of the first triode V1 and the other end of the protection resistor Rs.

[0043] A first capacitor C1 is provided between the base and the collector of the fifth triode V5; a seventh resistor R7 is provided between the base of the ninth triode V9 and the base of the third triode V3; a second capacitor C2 is provided between the base of the thirteenth triode V10 and the eighth resistor R8; the base of the thirteenth triode V10 is connected to the negative electrode of the first diode D1; the positive electrode of the first diode D1 is connected to the zero potential terminal; the other end of the protection resistor Rs is connected to the negative electrode of the second diode D2; the positive electrode of the second diode D2 is connected to the zero potential terminal.

[0044] Optionally, the seventh triode V7 and the eighth triode V8 are PNP type triodes; the first triode V1, the second triode V2, the third triode V3, the fourth triode V4, the fifth triode V5, the sixth triode V6, the ninth triode V9, the thirteenth triode V10, and the eleventh triode V11 are all NPN type triodes.

[0045] Wherein, the base current of the audio power tube is determined by the resistance value of the rheostat. When the resistance value of the rheostat becomes larger, the current of the entire circuit decreases. On the contrary, when the resistance value of the rheostat becomes smaller, the current of the entire circuit increases.

[0046] It can be understood that the controllable voltage regulator module can be equivalent to a TL431 controllable precision voltage regulator; the constant current bias module can be equivalent to a constant current diode with a current of 0.1 mA; as Figure 4 shown, it is equivalent to connecting the TL431 controllable precision voltage regulator U, the constant current diode D, and the triode BG1. The collector of the triode BG1 is connected to the positive pole of the constant current diode D; the base of the triode BG1 is connected to the negative pole of the constant current diode D and the reference terminal of the TL431 controllable precision voltage regulator U; the negative pole of the constant current diode D is connected to the cathode of the TL431 controllable precision voltage regulator U. At the same time, referring to Figure 3 , the anode of the TL431 controllable precision voltage regulator U is connected to the other end of the variable resistor RL; the emitter of the triode BG1 is connected to one end of the variable resistor RL; the collector of the triode BG1 is connected to the positive pole of the external voltage source. The other end of the variable resistor RL is connected to the zero potential terminal. Among them, RL is a sliding rheostat, and the resistance value of RL can be adjusted; the reference voltage of the TL431 controllable precision voltage regulator is 2.5 V, which is a forward bias voltage.

[0047] From Figure 3 and Figure 4 , it can be known that the lowest adjustable current of the entire circuit is 0.3 mA; among them, 0.1 mA is the current of the constant current diode D and is also the current of the TL431 controllable precision voltage regulator U, so the current of the TL431 controllable precision voltage regulator U is 0.1 mA; among them, the current of the variable resistor RL is 0.2 mA.

[0048] The current expansion module is used to expand the current on the basis of the reference constant current (0.1 mA). The variable constant current bias current range is 5 mA to 10 mA, which is determined by the resistance value of the variable resistor RL. Therefore, changing the resistance value of the variable resistor RL can change the constant current value of the constant current bias power triode BG1. Similarly, a larger current can be expanded.

[0049] Optionally, the audio power tube circuit can be packaged through a process. In this way, when applied, inputting an audio signal from the base of the audio power tube can achieve high-quality amplification of the audio signal without causing problems such as crossover distortion, saving the external circuit and design complexity.

[0050] The audio power tube circuit disclosed in this application, by setting a controllable voltage regulator module, a constant current bias module, and a current expansion module, and the current expansion module includes a constant current triode and a variable current circuit, realizes the purpose of providing an adjustable constant current for the audio power tube and protecting the audio power tube, broadens the usage range of the audio power tube, and ensures the working performance of the audio power tube.

[0051] The above description is only a preferred embodiment of the present disclosure and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of disclosure involved in the present disclosure is not limited to the technical solutions formed by the specific combination of the above technical features, but also covers other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosure concept. For example, the technical solutions formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present disclosure.

[0052] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application. The above is only the preferred implementation manner of the present application. It should be noted that due to the limited nature of written expression and the objectively infinite specific structures, for those of ordinary skill in the art, without departing from the principle of the present application, several improvements, refinements or changes can be made, or the above technical features can be combined in an appropriate manner; these improvements, refinements, changes or combinations, or directly applying the inventive concept and technical solution to other occasions without improvement, should all be regarded as the protection scope of the present application.

Claims

1. An audio power tube circuit, characterized in that, Comprising: A controllable voltage stabilizing source module, a constant current biasing module, and a current boosting module. The controllable voltage stabilizing source module, the constant current biasing module, and the current boosting module are connected to each other, and the current boosting module is connected to an audio power tube; Wherein, the constant current biasing module includes a MOS tube and a protection resistor; the current boosting module includes a constant current triode and a variable current circuit; The gate of the MOS tube is connected to the base of the constant current triode, the emitter of the constant current triode is connected to one end of the variable current circuit; the other end of the variable current circuit is connected to the controllable voltage stabilizing source module; the collector of the constant current triode is connected to the drain of the MOS tube and the positive pole of an external power supply, the source of the MOS tube is connected to one end of the protection resistor, and the other end of the protection resistor is connected to one end of the controllable voltage stabilizing circuit and the base of the constant current triode.

2. The audio power tube circuit according to claim 1, characterized in that, The variable current circuit includes a rheostat, one end of the rheostat is connected to the emitter of the constant current triode, and the other end of the rheostat is connected to the controllable voltage stabilizing source module.

3. The audio power tube circuit according to claim 1, wherein Further comprising: An overcurrent protection module, the overcurrent protection module is connected to the audio power tube.

4. The audio power tube circuit according to claim 3, wherein, The overcurrent protection module includes: an overcurrent protection triode and an overcurrent protection resistor; Wherein, the base of the overcurrent protection triode is connected to the emitter of the audio power tube and one end of the overcurrent protection resistor, the collector of the overcurrent protection triode is connected to the base of the audio power tube, and the emitter of the overcurrent protection triode is connected to the other end of the overcurrent protection resistor.

5. The audio power tube circuit according to claim 1, characterized in that, The controllable voltage stabilizing source module includes: a first drive circuit, a second drive circuit, a first Darlington circuit, a second Darlington circuit, a second triode, a fifth triode, and a ninth triode; Wherein, the emitter of the second triode is connected to the emitter of the first Darlington circuit and the constant current triode; the base of the second triode is connected to the collector of the second triode; the collector of the second triode is connected to the first drive circuit; the first drive circuit is further connected to the first Darlington circuit; the first Darlington circuit is further connected to the second drive circuit; the emitter of the fifth triode is connected to the first Darlington circuit; the base of the fifth triode is connected to the second drive circuit; the second drive circuit is further connected to the base of the ninth triode; the emitter of the fifth triode is connected to the emitter of the ninth triode; the collector of the ninth triode is connected to the first drive circuit and the second Darlington circuit; the second Darlington circuit is connected to the first drive circuit.

6. The audio power tube circuit according to claim 5, wherein The first Darlington circuit includes a first triode and a sixth triode; the second drive circuit includes a third triode, a fourth triode, a first resistor, a second resistor, a third resistor, and a fourth resistor; The collector of the first triode is respectively connected to the second Darlington circuit and the first drive circuit; the emitter of the first triode is connected to one end of the first resistor and the base of the sixth triode; the base of the first triode is connected to the emitter of the second triode; the other end of the first resistor is respectively connected to one end of the second resistor and one end of the third resistor; the other end of the second resistor is connected to the collector and the base of the third triode; the emitter of the third triode is connected to one end of the fourth resistor, the emitter of the fifth triode, the emitter of the ninth triode and the second Darlington circuit, and is simultaneously connected to the zero potential terminal; the base of the third triode is connected to the base of the fourth triode; the emitter of the fourth triode is connected to the other end of the fourth resistor; the collector of the fourth triode is connected to the other end of the third resistor and the base of the fifth triode; the collector of the fifth triode is connected to one end of the sixth resistor; the other end of the sixth resistor is connected to the emitter of the sixth triode; the collector of the sixth triode is connected to the first drive circuit.

7. The audio power tube circuit according to claim 6, wherein The second Darlington circuit includes a thirteenth triode, an eleventh triode, a ninth resistor and a tenth resistor; the first drive circuit includes a seventh triode, an eighth triode, a fifth resistor and an eighth resistor. The collector of the sixth triode is respectively connected to the collector and the base of the seventh triode; the emitter of the seventh triode is connected to one end of the fifth resistor; the base of the seventh triode is connected to the base of the eighth triode; the collector of the eighth triode is connected to the collector of the second triode and the collector of the ninth triode; the emitter of the eighth triode is connected to one end of the eighth resistor; the other ends of the fifth resistor and the eighth resistor are simultaneously connected to the collector of the first triode. The emitter of the thirteenth triode is connected to one end of the ninth resistor; the other end of the ninth resistor is respectively connected to the base of the eleventh triode and one end of the tenth resistor; the other end of the tenth resistor is connected to the emitter of the eleventh triode; the emitter of the eleventh triode is connected to the zero potential terminal; the base of the thirteenth triode is connected to the collector of the eighth triode and is connected to the collector of the ninth triode; the collector of the thirteenth triode and the collector of the eleventh triode are simultaneously connected to the collector of the first triode and the other end of the protection resistor.

8. The audio power tube circuit according to claim 7, characterized in that, A first capacitor is provided between the base and the collector of the fifth triode; a seventh resistor is provided between the base of the ninth triode and the base of the third triode; a second capacitor is provided between the base of the thirteenth triode and the eighth resistor; the base of the thirteenth triode is connected to the negative electrode of the first diode; the positive electrode of the first diode is connected to the zero potential terminal; the other end of the protection resistor is connected to the negative electrode of the second diode; the positive electrode of the second diode is connected to the zero potential terminal.

9. The audio power tube circuit according to claim 8, wherein The seventh triode and the eighth triode are PNP type triodes; the first triode, the second triode, the third triode, the fourth triode, the fifth triode, the sixth triode, the ninth triode, the thirteenth triode and the eleventh triode are all NPN type triodes.

10. The audio power tube circuit according to claim 2, wherein The base current of the audio power tube is determined by the resistance value of the rheostat; the audio power tube circuit is encapsulated by a process.

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