Detection circuit of discrete audio power amplifier

Abstract

The utility model relates to a detection circuit of a discrete audio power amplifier. The circuit comprises a current acquisition module which is connected with the output end of the audio power amplifier and is used for generating a voltage signal according to the current output by the audio power amplifier; the current detection module is connected with the current acquisition module and is used for pulling up the voltage signal output by the current acquisition module into a positive voltage signal and keeping the positive voltage signal; the voltage detection module is connected with the output end of the audio power amplifier and used for pulling up the voltage output by the audio power amplifier into a positive voltage signal and keeping the positive voltage signal; and the processor is respectively connected with the current detection module and the voltage detection module, and is used for determining the current output by the audio power amplifier according to the voltage signal output by the current detection module, determining the voltage output by the audio power amplifier according to the voltage signal output by the voltage detection module, and detecting a fault according to the current and voltage output by the audio power amplifier. According to the scheme, the deficiency of the fault detection function of the discrete audio power amplifier is filled, and the requirement on the sampling performance of the processor is low.

Description

Technical Field

[0001] The present disclosure relates to the field of audio power amplifier circuits, and in particular, to a detection circuit for a discrete audio power amplifier. Background Art

[0002] An audio amplifier is an audio power amplifier. It is an amplifier device used to drive a speaker to produce sound and reproduce sound. It is specifically used to amplify a smaller audio signal, increase its power, and then output it. Audio amplifiers are divided into integrated amplifiers and discrete amplifiers according to the degree of integration of their components. The principles of the two are the same. Due to size and process limitations, the output power of integrated amplifiers is limited, such as 50W and 60W. Discrete amplifiers are actually amplification inside integrated amplifiers, with each component assembled separately. Therefore, compared with integrated amplifiers, discrete amplifiers not only have high power, but also fuller sound. There is currently no reliable and simple circuit structure to detect the failure of discrete amplifiers. Utility Model Content

[0003] The purpose of the present disclosure is to provide a detection circuit for a discrete audio power amplifier, which can reliably detect faults of the discrete power amplifier.

[0004] In order to achieve the above object, the present disclosure provides a detection circuit of a discrete audio power amplifier, the detection circuit comprising:

[0005] A current acquisition module, connected to the output end of the audio power amplifier, and used to generate a voltage signal according to the current output by the audio power amplifier;

[0006] A current detection module, connected to the current acquisition module, for pulling up the voltage signal output by the current acquisition module into a positive voltage signal and maintaining it;

[0007] A voltage detection module, connected to the output terminal of the audio power amplifier, for pulling up the voltage output by the audio power amplifier into a positive voltage signal and maintaining it;

[0008] The processor is connected to the current detection module and the voltage detection module, respectively, and is used to determine the current output by the audio power amplifier according to the voltage signal output by the current detection module, determine the voltage output by the audio power amplifier according to the voltage signal output by the voltage detection module, and detect faults according to the current and voltage output by the audio power amplifier.

[0009] Optionally, the current acquisition module includes:

[0010] A current sampling resistor, connected in series to the output end of the audio power amplifier;

[0011] A differential amplifier circuit, wherein the input end of the differential amplifier circuit is connected to the two ends of the current sampling resistor, and the output end of the differential amplifier circuit serves as the output end of the current acquisition module.

[0012] Optionally, the current detection module includes:

[0013] A first pull-up resistor submodule, one end of which is connected to the input end of the current detection module, and the other end of which is connected to a predetermined first positive voltage, and the first pull-up resistor submodule is used to pull up the voltage input to the current detection module to a positive voltage;

[0014] A positive current detection submodule, connected to the input end of the current detection module, and used to maintain and output the positive value part of the voltage input to the current detection module;

[0015] The negative current detection submodule is connected to the input end of the current detection module and is used to maintain and output the negative value part of the voltage input to the current detection module.

[0016] Optionally, the first pull-up resistor submodule includes a second resistor;

[0017] The positive current detection submodule includes a first transistor, a third resistor, a fourth resistor and a second capacitor. The input end of the current detection module is connected to the base of the first transistor and to the collector of the first transistor through the third resistor. The collector of the first transistor is connected to a predetermined second positive voltage. The emitter of the first transistor is connected to one end of the fourth resistor and one end of the second capacitor. The other end of the fourth resistor and the other end of the second capacitor are grounded. One end of the second capacitor is connected to the positive current output end of the current detection module.

[0018] Optionally, the negative current detection submodule includes a second transistor, a fifth resistor, a sixth resistor and a fourth capacitor, the input end of the current detection module is connected to the base of the second transistor, and is connected to the collector of the second transistor through the fifth resistor, the collector of the first transistor is connected to a predetermined negative voltage, the emitter of the first transistor is connected to one end of the sixth resistor and one end of the fourth capacitor, the other end of the sixth resistor and the other end of the fourth capacitor are connected to the first positive voltage, and one end of the fourth capacitor is the negative current output end of the current detection module.

[0019] Optionally, the positive current detection submodule further includes a first diode and a first capacitor, one end of the first diode and one end of the first capacitor are connected to the base of the first transistor, and the other end of the first diode and the other end of the first capacitor are connected to the input end of the current detection module;

[0020] The negative current detection submodule also includes a second diode and a third capacitor, one end of the second diode and one end of the third capacitor are connected to the base of the second transistor, and the other end of the second diode and the other end of the third capacitor are connected to the input end of the current detection module.

[0021] Optionally, the positive current detection submodule further includes a seventh resistor and a ninth resistor, the emitter of the first transistor is connected to one end of the second capacitor through the seventh resistor, one end of the ninth resistor is connected to the emitter of the first transistor, and the other end is connected to the first positive voltage;

[0022] The negative current detection submodule also includes an eighth resistor and a tenth resistor, the emitter of the second transistor is connected to one end of the fourth capacitor through the eighth resistor, one end of the tenth resistor is connected to the emitter of the second transistor, and the other end is grounded.

[0023] Optionally, the voltage detection module includes:

[0024] a second pull-up resistor submodule, one end of the second pull-up resistor submodule is connected to the input end of the voltage detection module, and the other end is connected to a predetermined first positive voltage, and the first pull-up resistor submodule is used to pull up the voltage input to the voltage detection module to a positive voltage;

[0025] A positive voltage detection submodule, connected to the input end of the voltage detection module, and used to maintain and output the positive part of the voltage input to the voltage detection module;

[0026] The negative voltage detection submodule is connected to the input end of the voltage detection module and is used to maintain and output the negative value part of the voltage input to the voltage detection module.

[0027] Optionally, the second pull-up resistor submodule includes a twelfth resistor, a thirteenth resistor and a fourteenth resistor, the twelfth resistor and the thirteenth resistor are connected in series between the first positive voltage and the ground line, the input end of the voltage detection module is connected to a node between the twelfth resistor and the thirteenth resistor, and the twelfth resistor and the fourteenth resistor are connected in parallel;

[0028] The positive voltage detection submodule includes a fifteenth resistor, a seventeenth resistor, a fifth capacitor, a seventh capacitor, a third switch tube and a fifth switch tube, one end of the fifth capacitor and one end of the third switch tube are connected to the first positive voltage through the fifteenth resistor, the other end of the fifth capacitor and the other end of the third switch tube are connected to the input end of the voltage detection module, one end of the fifth capacitor and one end of the third switch tube are connected to one end of the fifth switch tube, the other end of the fifth switch tube is connected to the positive voltage output end of the voltage detection module, the other end of the fifth switch tube is connected to one end of the seventeenth resistor and one end of the seventh capacitor, the other end of the seventeenth resistor and the other end of the seventh capacitor are grounded, and one end of the seventh capacitor is connected to the positive voltage output end of the voltage detection module;

[0029] The negative voltage detection submodule includes a sixteenth resistor, an eighteenth resistor, a sixth capacitor, an eighth capacitor, a fourth switch tube and a sixth switch tube. One end of the sixth capacitor and one end of the fourth switch tube are grounded through the sixteenth resistor, the other end of the sixth capacitor and the other end of the fourth switch tube are connected to the input end of the voltage detection module, one end of the sixth capacitor and one end of the fourth switch tube are connected to one end of the sixth switch tube, the other end of the sixth switch tube is connected to one end of the eighteenth resistor and one end of the eighth capacitor, the other end of the eighteenth resistor and the other end of the eighth capacitor are connected to the first positive voltage, and one end of the eighth capacitor is connected to the negative voltage output end of the voltage detection module.

[0030] Optionally, the third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are triodes or diodes.

[0031] Optionally, the positive voltage detection submodule further includes a nineteenth resistor and a twenty-first resistor, the nineteenth resistor is connected between the other end of the fifth switch tube and one end of the seventh capacitor, and the twenty-first resistor is connected between the other end of the fifth switch tube and the first positive voltage;

[0032] The negative voltage detection submodule also includes a twentieth resistor and a twenty-second resistor, the twenty-second resistor is connected between the other end of the sixth switch tube and one end of the eighth capacitor, and the twenty-second resistor is connected between the other end of the sixth switch tube and the ground line.

[0033] Through the above technical solution, the current signal output by the audio power amplifier is pulled up into a positive voltage signal and maintained by the current acquisition module and the current detection module, and the voltage signal output by the audio power amplifier is also pulled up into a positive voltage signal and maintained by the voltage detection module. In this way, on the one hand, the bidirectional current and bidirectional voltage output by the audio power amplifier are converted into positive voltages that can be read by the processor, which makes it easier for the processor to determine the voltage and current output by the audio power amplifier based on the read voltage, thus filling the gap in the fault detection function of the discrete audio power amplifier; on the other hand, since the voltage signal is maintained, the processor is allowed to collect data at a lower frequency, which places lower requirements on the sampling performance of the processor, and even if a low-computing-power processor is used, fault diagnosis can be performed accurately.

[0034] Other features and advantages of the present disclosure will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure but do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0036] Figure 1 It is a structural block diagram of a detection circuit of a discrete audio power amplifier provided by an exemplary embodiment.

[0037] Figure 2 is a structural block diagram of a detection circuit of a discrete audio power amplifier provided by another exemplary embodiment.

[0038] Figure 3 It is a structural schematic diagram of a current detection module provided by an exemplary embodiment.

[0039] Figure 4 is a structural schematic diagram of a current detection module provided by another exemplary embodiment.

[0040] Figure 5 is a structural schematic diagram of a current detection module provided by yet another exemplary embodiment.

[0041] Figure 6 It is a structural diagram of a voltage detection module provided by an exemplary embodiment.

[0042] Figure 7 is a structural diagram of a voltage detection module provided by another exemplary embodiment.

[0043] Figure 8 is a structural diagram of a voltage detection module provided by yet another exemplary embodiment.

[0044] Fig. 9 is a structural diagram of a voltage detection module provided by yet another exemplary embodiment.

[0045] Description of Reference Numerals

[0046] 100 audio amplifier 200 detection circuit 10 current acquisition module

[0047] 20 current detection module 30 voltage detection module 40 processor

[0048] 11 Current sampling resistor 12 Differential amplifier circuit R1 First resistor

[0049] R2 second resistor R3 third resistor R4 fourth resistor

[0050] R5 fifth resistor R6 sixth resistor R7 seventh resistor

[0051] R8 eighth resistor R9 ninth resistor R10 tenth resistor

[0052] R11 11th resistor R12 12th resistor R13 13th resistor

[0053] R14 is the fourteenth resistor. R15 is the fifteenth resistor. R16 is the sixteenth resistor.

[0054] R17 17th resistor R18 18th resistor C1 1st capacitor

[0055] C2 Second capacitor C3 Third capacitor C4 Fourth capacitor

[0056] C5 fifth capacitor C6 sixth capacitor C7 seventh capacitor

[0057] C8 The eighth capacitor D1 The first diode D2 The second diode

[0058] Q1 is the first transistor Q2 is the second transistor Q3 is the third switch

[0059] Q4 the fourth switch tube Q5 the fifth switch tube Q6 the sixth switch tube

[0060] R19 19th resistor R20 20th resistor R21 21st resistor

[0061] R22 22nd resistor DETAILED DESCRIPTION

[0062] The specific implementation of the present disclosure is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described herein is only used to illustrate and explain the present disclosure, and is not used to limit the present disclosure.

[0063] Figure 1 FIG. 1 is a block diagram of a detection circuit of a discrete audio power amplifier provided by an exemplary embodiment. Figure 1As shown, the detection circuit 200 of the discrete audio power amplifier 100 includes a current acquisition module 10 , a current detection module 20 , a voltage detection module 30 and a processor 40 .

[0064] The current acquisition module 10 is connected to the output end of the audio power amplifier 100 and is used to generate a voltage signal according to the current output by the audio power amplifier.

[0065] The current detection module 20 is connected to the current acquisition module 10 and is used to pull up the voltage signal output by the current acquisition module 10 into a positive voltage signal and maintain it.

[0066] The voltage detection module 30 is connected to the output terminal of the audio power amplifier 100 and is used to pull up the voltage output by the audio power amplifier into a positive voltage signal and maintain it.

[0067] The processor 40 is connected to the current detection module 20 and the voltage detection module 30 respectively, and is used to determine the current output by the audio power amplifier according to the voltage signal output by the current detection module 20, determine the voltage output by the audio power amplifier according to the voltage signal output by the voltage detection module 30, and detect faults according to the current and voltage output by the audio power amplifier.

[0068] The current and voltage output by the audio power amplifier 100 are both bidirectional, that is, they have positive and negative values, and the level signal that the processor can usually receive is a voltage signal greater than or equal to zero. The above-mentioned positive voltage signal includes a voltage signal greater than or equal to zero. Through the above technical solution, the current acquisition module and the current detection module are used to pull up the current signal output by the audio power amplifier into a positive voltage signal and maintain it, and the voltage detection module is used to pull up the voltage signal output by the audio power amplifier into a positive voltage signal and maintain it.

[0069] In this way, on the one hand, the bidirectional current and bidirectional voltage output by the audio power amplifier are converted into positive voltages that can be read by the processor, making it easier for the processor to determine the voltage and current output by the audio power amplifier based on the read voltage, filling the lack of fault detection function for discrete audio power amplifiers; on the other hand, since the voltage signal is maintained, the processor is allowed to collect data at a lower frequency, which places lower requirements on the sampling performance of the processor, and even if a low-computing power processor is used, fault diagnosis can be accurately performed.

[0070] Figure 2 FIG. 1 is a block diagram of a detection circuit of a discrete audio power amplifier provided by another exemplary embodiment. Figure 2 As shown, the current acquisition module 10 includes a current sampling resistor 11 and a differential amplifier circuit 12 .

[0071] The current sampling resistor 11 is connected in series to the output end of the audio power amplifier 100 . The input end of the differential amplifier circuit 12 is connected to both ends of the current sampling resistor 11 , and the output end of the differential amplifier circuit serves as the output end of the current acquisition module 10 .

[0072] In this embodiment, the output current of the audio power amplifier 100 can be reliably collected by using a simple sampling resistor and a differential amplifier circuit.

[0073] In yet another embodiment, the current detection module 20 includes a first pull-up resistor submodule, a positive current detection submodule, and a negative current detection submodule.

[0074] One end of the first pull-up resistor submodule is connected to the input end of the current detection module 20 , and the other end is connected to a predetermined first positive voltage. The first pull-up resistor submodule is used to pull up the voltage of the input current detection module 20 to a positive voltage.

[0075] The positive current detection submodule is connected to the input end of the current detection module 20 and is used to maintain and output the positive value portion of the voltage input to the current detection module 20 .

[0076] The negative current detection submodule is connected to the input end of the current detection module 20 and is used to maintain and output the negative value portion of the voltage input to the current detection module 20 .

[0077] In this embodiment, two independent circuits are provided to respectively detect the positive part and the negative part of the output current of the audio power amplifier, and the processor receives the positive part and the negative part of the current respectively, so that the two parts of the sampling data do not affect each other, thereby enhancing the reliability of the discrete audio power amplifier fault detection.

[0078] Figure 3 FIG. 1 is a schematic diagram of the structure of a current detection module provided by an exemplary embodiment. Figure 3 As shown, the input voltage of the current detection module 20 is V1, and the first resistor R1 is a load resistor. The first pull-up resistor submodule includes a second resistor R2. The predetermined first positive voltage is +5V. For example, through the first pull-up resistor submodule and the first positive voltage, the -5 to +5V signal is converted into a 0-5V signal, thereby solving the problem that the processor MCU cannot read negative voltage.

[0079] The positive current detection submodule includes a first transistor Q1, a third resistor R3, a fourth resistor R4 and a second capacitor C2. The input end of the current detection module 20 is connected to the base of the first transistor Q1, and is connected to the collector of the first transistor Q1 through the third resistor R3. The collector of the first transistor Q1 is connected to a predetermined second positive voltage (+15V), and the emitter of the first transistor Q1 is connected to one end of the fourth resistor R4 and one end of the second capacitor C2. The other end of the fourth resistor R4 and the other end of the second capacitor C2 are grounded. One end of the second capacitor C2 is connected to the positive current output end of the current detection module 20.

[0080] The first transistor Q1 forms an emitter follower circuit. When the voltage of the input current detection module 20 increases to the maximum, the input voltage of the positive current detection submodule increases to the maximum, and the voltage of the second capacitor C2 increases to the maximum value synchronously. The emitter voltage of the first transistor Q1 will follow the base voltage, that is, the voltage of the second capacitor C2 will store the positive peak voltage and output it to the processor. The positive peak voltage corresponds to the positive peak output current Ipk+ of the audio power amplifier 100.

[0081] The negative current detection submodule includes a second triode Q2, a fifth resistor R5, a sixth resistor R6 and a fourth capacitor C4. The input end of the current detection module 20 is connected to the base of the second triode Q2, and is connected to the collector of the second triode Q2 through the fifth resistor R5. The collector of the first triode Q1 is connected to a predetermined negative voltage (-15V), the emitter of the first triode Q1 is connected to one end of the sixth resistor R6 and one end of the fourth capacitor C4, and the other end of the sixth resistor R6 and the other end of the fourth capacitor C4 are connected to a first positive voltage (+5V). One end of the fourth capacitor C4 is the negative current output end of the current detection module 20.

[0082] The second transistor Q2 forms an emitter follower circuit. When the voltage of the input current detection module 20 is reduced to a minimum, the input voltage of the negative current detection submodule is reduced to a minimum, and the voltage of the fourth capacitor C4 is reduced to a minimum value synchronously. The emitter voltage of the second transistor Q2 will follow the base voltage, that is, the voltage of the fourth capacitor C4 will store a negative peak voltage and output it to the processor. The negative peak voltage corresponds to the negative peak output current Ipk- of the audio power amplifier 100.

[0083] The first positive voltage, the second positive voltage and the predetermined negative voltage may be directly provided by a power supply, or may be voltages input from an external circuit.

[0084] In this embodiment, an emitter follower circuit and a capacitor are used to follow and maintain the voltage. The voltage corresponding to the positive peak output current Ipk+ is output at the positive current output terminal, and the voltage corresponding to the negative peak output current Ipk- is output at the negative current output terminal. The circuit is simple and reliable.

[0085] Figure 4 FIG. 1 is a schematic diagram of the structure of a current detection module provided by another exemplary embodiment. Figure 4 As shown, in Figure 3 On the basis of, the positive current detection submodule also includes a first diode D1 and a first capacitor C1, one end of the first diode D1 and one end of the first capacitor C1 are connected to the base of the first transistor Q1, and the other end of the first diode D1 and the other end of the first capacitor C1 are connected to the input end of the current detection module 20.

[0086] The negative current detection submodule also includes a second diode D2 and a third capacitor C3, one end of the second diode D2 and one end of the third capacitor C3 are connected to the base of the second transistor Q2, and the other end of the second diode D2 and the other end of the third capacitor C3 are connected to the input end of the current detection module 20.

[0087] In this embodiment, the first diode D1 connected in series can compensate for the Ube voltage drop of the first transistor Q1, and the second diode D2 connected in series can compensate for the Ube voltage drop of the second transistor Q2, so that the detected data is more accurate. The first diode D1 can also be replaced by a transistor of the same model as the first transistor Q1, and the second diode D2 can also be replaced by a transistor of the same model as the second transistor Q2, to achieve a better compensation effect.

[0088] Figure 5 FIG. 1 is a schematic diagram of the structure of a current detection module provided by another exemplary embodiment. Figure 5 As shown, in Figure 4 On the basis of, the positive current detection submodule also includes a seventh resistor R7 and a ninth resistor R9. The emitter of the first transistor Q1 is connected to one end of the second capacitor C2 through the seventh resistor R7, and one end of the ninth resistor R9 is connected to the emitter of the first transistor Q1, and the other end is connected to the first positive voltage.

[0089] The negative current detection submodule further includes an eighth resistor R8 and a tenth resistor R10. The emitter of the second transistor Q2 is connected to one end of the fourth capacitor C4 through the eighth resistor R8, and one end of the tenth resistor R10 is connected to the emitter of the second transistor Q2 and the other end is grounded.

[0090] Among them, the ninth resistor R9 is added to realize the forward half-wave rectification, and then the positive peak current stored in the second capacitor C2 is converted into the forward average current Iav+ through the RC filter circuit composed of the seventh resistor R7 and the second capacitor C2.

[0091] The tenth resistor R10 is added to realize negative half-wave rectification, and then the negative peak current stored in the fourth capacitor C4 is converted into a negative average current Iav- through the RC filter circuit composed of the eighth resistor R8 and the fourth capacitor C4.

[0092] In this embodiment, the average positive and negative currents are output, and the open circuit and short circuit states of the load of the audio power amplifier can be determined according to the average positive and negative currents.

[0093] In yet another embodiment, the voltage detection module 30 includes a second pull-up resistor submodule, a positive voltage detection submodule, and a negative voltage detection submodule.

[0094] One end of the second pull-up resistor submodule is connected to the input end of the voltage detection module 30 , and the other end is connected to a predetermined first positive voltage. The first pull-up resistor submodule is used to pull up the voltage of the input voltage detection module 30 to a positive voltage.

[0095] The positive voltage detection submodule is connected to the input end of the voltage detection module 30 and is used to maintain and output the positive value portion of the voltage input to the voltage detection module 30 .

[0096] The negative voltage detection submodule is connected to the input end of the voltage detection module 30 and is used to maintain and output the negative value portion of the voltage input to the voltage detection module 30 .

[0097] In this embodiment, two independent circuits are provided to respectively detect the positive part and the negative part of the output voltage of the audio power amplifier, and the processor receives the positive part and the negative part of the voltage respectively, so that the two parts of the sampling data do not affect each other, thereby enhancing the reliability of the discrete audio power amplifier fault detection.

[0098] Figure 6 FIG. 1 is a schematic diagram of a voltage detection module provided by an exemplary embodiment. Figure 6 As shown, the second pull-up resistor submodule includes a twelfth resistor R12, a thirteenth resistor R13 and a fourteenth resistor R14, the twelfth resistor R12 and the thirteenth resistor R13 are connected in series between the first positive voltage (+5V) and the ground line, the input end of the voltage detection module 30 is connected to the node between the twelfth resistor R12 and the thirteenth resistor R13, and the twelfth resistor R12 and the fourteenth resistor R14 are connected in parallel.

[0099] The positive voltage detection submodule includes a fifteenth resistor R15, a seventeenth resistor R17, a fifth capacitor C5, a seventh capacitor C7, a third switch tube Q3 and a fifth switch tube Q5. One end of the fifth capacitor C5 and one end of the third switch tube Q3 are connected to the first positive voltage (+5V) through the fifteenth resistor R15. The other end of the fifth capacitor C5 and the other end of the third switch tube Q3 are connected to the input end of the voltage detection module 30. One end of the fifth capacitor C5 and one end of the third switch tube Q3 are connected to one end of the fifth switch tube Q5. The other end of the fifth switch tube Q5 is connected to the positive voltage output end of the voltage detection module 30. The other end of the fifth switch tube Q5 is connected to one end of the seventeenth resistor R17 and one end of the seventh capacitor C7. The other end of the seventeenth resistor R17 and the other end of the seventh capacitor C7 are grounded. One end of the seventh capacitor C7 is connected to the positive voltage output end of the voltage detection module 30.

[0100] When the voltage of the input voltage detection module 30 increases to the maximum, the input voltage of the positive voltage detection submodule increases to the maximum, the voltage of the seventh capacitor C7 increases to the maximum value synchronously, and the voltage of the seventh capacitor C7 stores the positive peak voltage and outputs it to the processor. The positive peak voltage corresponds to the positive peak output voltage Vpk+ of the audio power amplifier 100.

[0101] The negative voltage detection submodule includes a sixteenth resistor R16, an eighteenth resistor R18, a sixth capacitor C6, an eighth capacitor C8, a fourth switch tube Q4 and a sixth switch tube Q6. One end of the sixth capacitor C6 and one end of the fourth switch tube Q4 are grounded through the sixteenth resistor R16. The other end of the sixth capacitor C6 and the other end of the fourth switch tube Q4 are connected to the input end of the voltage detection module 30. One end of the sixth capacitor C6 and one end of the fourth switch tube Q4 are connected to one end of the sixth switch tube Q6. The other end of the sixth switch tube Q6 is connected to one end of the eighteenth resistor R18 and one end of the eighth capacitor C8. The other end of the eighteenth resistor R18 and the other end of the eighth capacitor C8 are connected to the first positive voltage (+5V). One end of the eighth capacitor C8 is connected to the negative voltage output end of the voltage detection module 30.

[0102] When the voltage of the input voltage detection module 30 is reduced to a minimum, the input voltage of the negative voltage detection submodule is reduced to a minimum, and the voltage of the eighth capacitor C8 is simultaneously reduced to a minimum value, and the voltage of the eighth capacitor C8 stores a negative peak voltage and outputs it to the processor. The negative peak voltage corresponds to the negative peak output voltage Vpk- of the audio power amplifier 100.

[0103] In this embodiment, voltage following and holding are performed, a voltage signal corresponding to the positive peak output voltage Vpk+ is output at the positive voltage output terminal, and a voltage corresponding to the negative peak output voltage Vpk- is output at the negative voltage output terminal. The circuit is simple and reliable.

[0104] The third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 can be triodes or diodes. Figure 6 In the embodiment, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 are all diodes.

[0105] Figure 7 is a structural diagram of a voltage detection module provided by another exemplary embodiment. Figure 8 FIG. 1 is a schematic diagram of the structure of a voltage detection module provided by another exemplary embodiment. Figure 7 In the embodiment, the third switch tube Q3 and the fourth switch tube Q4 are diodes, and the fifth switch tube Q5 and the sixth switch tube Q6 are triodes. Figure 8 In the embodiment, the third switch tube Q3, the fourth switch tube Q4, the fifth switch tube Q5 and the sixth switch tube Q6 are all triodes.

[0106] Fig. 9 FIG. 1 is a schematic diagram of a voltage detection module provided by another exemplary embodiment. Fig. 9 As shown, the positive voltage detection submodule further includes a nineteenth resistor R19 and a twenty-first resistor R21. The nineteenth resistor R19 is connected between the other end of the fifth switch tube Q5 and one end of the seventh capacitor C7, and the twenty-first resistor R21 is connected between the other end of the fifth switch tube Q5 and the first positive voltage.

[0107] The negative voltage detection submodule further includes a 20th resistor R20 and a 22nd resistor R22. The 20th resistor R20 is connected between the other end of the sixth switch tube Q6 and one end of the eighth capacitor C8, and the 22nd resistor R22 is connected between the other end of the sixth switch tube Q6 and the ground line.

[0108] Among them, the twenty-first resistor R21 is added to realize the forward half-wave rectification, and then the positive peak voltage stored on the seventh capacitor C7 is converted into the forward average voltage Vav+ through the RC filter circuit composed of the nineteenth resistor R19 and the seventh capacitor C7.

[0109] The twenty-second resistor R22 is added to realize negative half-wave rectification, and then the negative peak voltage stored on the eighth capacitor C8 is converted into a negative average voltage Vav- through the RC filter circuit composed of the twentieth resistor R20 and the eighth capacitor C8.

[0110] In this embodiment, the average positive and negative voltages are output, and the open circuit and short circuit states of the load of the audio power amplifier can be determined according to the average positive and negative voltages.

[0111] According to the circuit structure, the processor can convert the voltage signal transmitted by the current detection module into the output current value of the audio power amplifier, and convert the voltage signal transmitted by the voltage detection module into the output voltage value of the audio power amplifier, and then obtain the load impedance R of the audio power amplifier from the ratio of the converted current value and voltage value.

[0112] For example, the load impedance R of the audio power amplifier can be obtained by dividing the positive peak output voltage Vpk+ by the positive peak output current Ipk+, or by dividing the negative peak output voltage Vpk- by the negative peak output current Ipk-. The load impedance R of the audio power amplifier can also be obtained by dividing the positive average voltage Vav+ by the positive average current Iav+, or by dividing the negative average voltage Vav- by the negative average current Iav-.

[0113] According to the load impedance R, the load open circuit, short circuit and other states can be judged, as follows:

[0114] (1) If the impedance is 0≤R≤Rth (impedance threshold), it is determined that the audio power amplifier is short-circuited to ground fault;

[0115] (2) If the impedance Rth < R < Rmin (lower impedance limit value), then it is determined that the audio power amplifier has an overload fault;

[0116] (3) If the impedance Rmin ≤ R ≤ Rmax (upper impedance limit value), then it is determined that the audio power amplifier is operating normally;

[0117] (4) If the impedance R > Rmax, then it is determined that the audio power amplifier has a short - circuit to the power supply fault or an open - circuit fault;

[0118] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above - mentioned embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0119] In addition, it should be noted that, among the various specific technical features described in the above - mentioned specific embodiments, they can be combined in any appropriate manner without contradiction. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination methods.

[0120] Furthermore, any combination can be made among various different embodiments of the present disclosure as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A detection circuit for a discrete audio power amplifier, characterized in that: The detection circuit comprises: A current acquisition module, connected to the output end of the audio power amplifier, and used to generate a voltage signal according to the current output by the audio power amplifier; A current detection module, connected to the current acquisition module, for pulling up the voltage signal output by the current acquisition module into a positive voltage signal and maintaining it; A voltage detection module, connected to the output terminal of the audio power amplifier, for pulling up the voltage output by the audio power amplifier into a positive voltage signal and maintaining it; The processor is connected to the current detection module and the voltage detection module respectively, and is used to determine the current output by the audio power amplifier according to the voltage signal output by the current detection module, determine the voltage output by the audio power amplifier according to the voltage signal output by the voltage detection module, and detect faults according to the current and voltage output by the audio power amplifier.

2. The detection circuit according to claim 1, characterized in that: The current acquisition module comprises: A current sampling resistor, connected in series to the output end of the audio power amplifier; A differential amplifier circuit, wherein the input end of the differential amplifier circuit is connected to the two ends of the current sampling resistor, and the output end of the differential amplifier circuit serves as the output end of the current acquisition module.

3. The detection circuit according to claim 1, characterized in that: The current detection module comprises: A first pull-up resistor submodule, one end of which is connected to the input end of the current detection module, and the other end of which is connected to a predetermined first positive voltage, and the first pull-up resistor submodule is used to pull up the voltage input to the current detection module to a positive voltage; A positive current detection submodule, connected to the input end of the current detection module, and used to maintain and output the positive value part of the voltage input to the current detection module; The negative current detection submodule is connected to the input end of the current detection module and is used to maintain and output the negative value part of the voltage input to the current detection module.

4. The detection circuit according to claim 3, characterized in that: The first pull-up resistor submodule includes a second resistor; The positive current detection submodule includes a first transistor, a third resistor, a fourth resistor and a second capacitor. The input end of the current detection module is connected to the base of the first transistor and to the collector of the first transistor through the third resistor. The collector of the first transistor is connected to a predetermined second positive voltage. The emitter of the first transistor is connected to one end of the fourth resistor and one end of the second capacitor. The other end of the fourth resistor and the other end of the second capacitor are grounded. One end of the second capacitor is connected to the positive current output end of the current detection module.

5. The detection circuit according to claim 4, characterized in that: The negative current detection submodule includes a second transistor, a fifth resistor, a sixth resistor and a fourth capacitor. The input end of the current detection module is connected to the base of the second transistor and to the collector of the second transistor through the fifth resistor. The collector of the first transistor is connected to a predetermined negative voltage. The emitter of the first transistor is connected to one end of the sixth resistor and one end of the fourth capacitor. The other end of the sixth resistor and the other end of the fourth capacitor are connected to the first positive voltage. One end of the fourth capacitor is the negative current output end of the current detection module.

6. The detection circuit according to claim 5, characterized in that: The positive current detection submodule further includes a first diode and a first capacitor, one end of the first diode and one end of the first capacitor are connected to the base of the first transistor, and the other end of the first diode and the other end of the first capacitor are connected to the input end of the current detection module; The negative current detection submodule also includes a second diode and a third capacitor, one end of the second diode and one end of the third capacitor are connected to the base of the second transistor, and the other end of the second diode and the other end of the third capacitor are connected to the input end of the current detection module.

7. The detection circuit according to claim 5 or 6, characterized in that: The positive current detection submodule further includes a seventh resistor and a ninth resistor, the emitter of the first transistor is connected to one end of the second capacitor through the seventh resistor, one end of the ninth resistor is connected to the emitter of the first transistor, and the other end is connected to the first positive voltage; The negative current detection submodule also includes an eighth resistor and a tenth resistor, the emitter of the second transistor is connected to one end of the fourth capacitor through the eighth resistor, one end of the tenth resistor is connected to the emitter of the second transistor, and the other end is grounded.

8. The detection circuit according to claim 1, characterized in that: The voltage detection module comprises: a second pull-up resistor submodule, one end of the second pull-up resistor submodule is connected to the input end of the voltage detection module, and the other end is connected to a predetermined first positive voltage, and the second pull-up resistor submodule is used to pull up the voltage input to the voltage detection module to a positive voltage; A positive voltage detection submodule, connected to the input end of the voltage detection module, and used to maintain and output the positive part of the voltage input to the voltage detection module; The negative voltage detection submodule is connected to the input end of the voltage detection module and is used to maintain and output the negative value part of the voltage input to the voltage detection module.

9. The detection circuit according to claim 8, characterized in that: The second pull-up resistor submodule includes a twelfth resistor, a thirteenth resistor and a fourteenth resistor, the twelfth resistor and the thirteenth resistor are connected in series between the first positive voltage and the ground line, the input end of the voltage detection module is connected to the node between the twelfth resistor and the thirteenth resistor, and the twelfth resistor and the fourteenth resistor are connected in parallel; The positive voltage detection submodule includes a fifteenth resistor, a seventeenth resistor, a fifth capacitor, a seventh capacitor, a third switch tube and a fifth switch tube, one end of the fifth capacitor and one end of the third switch tube are connected to the first positive voltage through the fifteenth resistor, the other end of the fifth capacitor and the other end of the third switch tube are connected to the input end of the voltage detection module, one end of the fifth capacitor and one end of the third switch tube are connected to one end of the fifth switch tube, the other end of the fifth switch tube is connected to the positive voltage output end of the voltage detection module, the other end of the fifth switch tube is connected to one end of the seventeenth resistor and one end of the seventh capacitor, the other end of the seventeenth resistor and the other end of the seventh capacitor are grounded, and one end of the seventh capacitor is connected to the positive voltage output end of the voltage detection module; The negative voltage detection submodule includes a sixteenth resistor, an eighteenth resistor, a sixth capacitor, an eighth capacitor, a fourth switch tube and a sixth switch tube. One end of the sixth capacitor and one end of the fourth switch tube are grounded through the sixteenth resistor, the other end of the sixth capacitor and the other end of the fourth switch tube are connected to the input end of the voltage detection module, one end of the sixth capacitor and one end of the fourth switch tube are connected to one end of the sixth switch tube, the other end of the sixth switch tube is connected to one end of the eighteenth resistor and one end of the eighth capacitor, the other end of the eighteenth resistor and the other end of the eighth capacitor are connected to the first positive voltage, and one end of the eighth capacitor is connected to the negative voltage output end of the voltage detection module.

10. The detection circuit according to claim 9, characterized in that: The third switch tube, the fourth switch tube, the fifth switch tube and the sixth switch tube are triodes or diodes.

11. The detection circuit according to claim 9, characterized in that: The positive voltage detection submodule further includes a nineteenth resistor and a twenty-first resistor, the nineteenth resistor is connected between the other end of the fifth switch tube and one end of the seventh capacitor, and the twenty-first resistor is connected between the other end of the fifth switch tube and the first positive voltage; The negative voltage detection submodule also includes a twentieth resistor and a twenty-second resistor, the twenty-second resistor is connected between the other end of the sixth switch tube and one end of the eighth capacitor, and the twenty-second resistor is connected between the other end of the sixth switch tube and the ground line.

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