Power amplifier protection circuit

Abstract

The embodiment of the utility model discloses a power amplifier protection circuit. The power amplifier protection circuit comprises a power amplifier power supply detection module, a power amplifier input detection module, a first triode, a relay and a fault indication module. Wherein the first triode is cut off when the output end of the power amplifier power supply detection module outputs a first voltage signal, controls the relay to disconnect the power amplifier load when the output end of the power amplifier input detection module outputs a second voltage signal, and indicates the fault indication module to display a fault signal source. According to the embodiment of the utility model, the input states of the power amplifier power supply and the multi-channel power amplifier signal are detected, the stability, the reliability and the maintainability of the audio power amplifier system are improved, and the normal operation and the service life of audio equipment are ensured.

Description

Technical Field

[0001] This utility model relates to the field of audio amplifier technology, and in particular to a power amplifier protection circuit. Background Technology

[0002] Amplifier protection circuitry is a component of an audio amplifier used to protect the amplifier circuitry and speakers from damage in the event of an abnormal amplifier input.

[0003] In audio amplifier circuits of audio equipment, there are often multiple audio inputs. When any of these inputs malfunctions, transmitting the abnormal audio input to the speakers can cause sound distortion, hum, or other forms of noise, and may even damage the amplifier itself. Current technology uses components such as fuses or varistors connected in series in the circuit to disconnect the power supply and protect the amplifier circuit when an abnormality occurs at the audio input.

[0004] However, existing technical solutions cannot effectively monitor and protect against faults not caused by overvoltage, nor can they detect which specific amplifier audio input abnormality caused the amplifier fault. Utility Model Content

[0005] This invention provides a power amplifier protection circuit that can simultaneously monitor the status of multiple power amplifiers and disconnect the power supply to the power amplifier when any power amplifier circuit experiences an input abnormality, thereby protecting the power amplifier circuit.

[0006] This utility model embodiment provides a power amplifier protection circuit, including: a power amplifier power detection module, the input terminal of which is connected to the power amplifier power output terminal, and the output terminal is configured to output a first voltage signal when the power amplifier power output terminal outputs a power amplifier power signal;

[0007] A power amplifier input detection module includes at least one input terminal, different input terminals are connected to different power amplifier signal output terminals, and the output terminal is configured to output a second voltage signal when at least one power amplifier signal output terminal does not output a power amplifier signal;

[0008] The first transistor has its collector connected to the first power supply, and its base connected to the output of the power amplifier power supply detection module and the output of the power amplifier input detection module, respectively. The first transistor is configured to be cut off when the power amplifier power supply detection module outputs a first voltage signal, and to be turned on when the power amplifier input detection module outputs a second voltage signal.

[0009] The relay's control terminal is connected to the emitter of the first transistor, its common terminal is connected to the power amplifier's power output terminal, its normally closed terminal is connected to the power amplifier's load, and its normally open terminal is connected to the fault indication module.

[0010] The fault indication module has its control terminal connected to the normally open terminal of the relay. The fault indication module is configured to indicate a fault when the common terminal and the normally open terminal of the relay are connected.

[0011] Optionally, the power amplifier power supply detection module includes an optocoupler, which includes a first terminal, a second terminal, a third terminal, and a fourth terminal;

[0012] The first terminal is connected to the power amplifier power output terminal; the second terminal is connected to the ground terminal; the fourth terminal is connected to the first power supply; the fourth terminal is connected to the base of the first transistor; the third terminal outputs the first power supply voltage when the power amplifier power signal is output at the power amplifier power output terminal.

[0013] Optionally, the power amplifier power supply detection module may also include a first light-emitting diode, a first resistor, a second resistor, a first capacitor, and a first diode;

[0014] The first resistor is placed between the fourth terminal and the first power supply; the second resistor is placed between the power amplifier power output terminal and the first terminal; the first light-emitting diode and the first diode are placed between the second terminal and the ground terminal; the first capacitor is placed between the first terminal and the second terminal.

[0015] Optionally, the power amplifier input detection module includes at least one switching unit, which is connected in series between the base of the first transistor and the ground terminal;

[0016] The control terminal of the switching unit serves as the input terminal of the power amplifier input detection module and is connected to the power amplifier signal output terminal. The switching unit is turned on when the control terminal receives the power amplifier signal output from the power amplifier signal output terminal, and turned off when the control terminal does not receive the power amplifier signal output from the power amplifier signal output terminal.

[0017] Optionally, the switching unit includes a second transistor, a third resistor, and a second diode;

[0018] The power amplifier signal output terminal is connected to the control terminal of the switching unit through a second diode and a third resistor connected in series.

[0019] Optionally, the power amplifier input detection module also includes at least one output status indicator unit, which is the same number as the number of switching units. The output status indicator units are connected in series between the power amplifier signal output terminal and the ground terminal of each switching unit.

[0020] The output status indicator unit is configured to indicate when a power amplifier signal is output at the power amplifier signal output terminal.

[0021] Optionally, the output status indicator unit includes a fourth resistor and a second light-emitting diode; the fourth resistor and the second light-emitting diode are connected in series between the power amplifier signal output terminal and the ground terminal.

[0022] Optionally, the fault indication module includes a first fault indication unit and a second fault indication unit, the power amplifier power output terminal includes a first power amplifier power output terminal and a second power amplifier power output terminal, and the relay includes a first common terminal, a second common terminal, a first normally open terminal and a second normally open terminal.

[0023] The first common terminal is connected to the output terminal of the first power amplifier, and the second common terminal is connected to the output terminal of the second power amplifier; the first fault indicator unit is connected between the first normally open terminal and the ground terminal, and the second fault indicator unit is connected between the second normally open terminal and the ground terminal.

[0024] The first fault indication unit is configured to indicate a fault when the first common terminal and the first normally open terminal are connected, and the second fault indication unit is configured to indicate a fault when the first common terminal and the first normally open terminal are connected.

[0025] Optionally, the first fault indication unit includes a fifth resistor, a sixth resistor, and a third light-emitting diode. The first normally open terminal is connected to the ground terminal through the fifth resistor. The first normally open terminal is also connected to the ground terminal through the third light-emitting diode and the sixth resistor connected in series.

[0026] The second fault indication unit includes a seventh resistor, an eighth resistor, and a fourth light-emitting diode.

[0027] The second normally open terminal is connected to the ground terminal through the seventh resistor; the second normally open terminal is also connected to the ground terminal through the fourth light-emitting diode and the eighth resistor connected in series.

[0028] Optionally, the first fault indication unit further includes a second capacitor, which is connected to the power output terminal of the first power amplifier.

[0029] The second fault indication unit also includes a third capacitor, which is connected to the power output terminal of the second power amplifier.

[0030] This utility model provides a power amplifier protection circuit, including: a power amplifier power supply detection module, a power amplifier input detection module, a first transistor, a relay, and a fault indication module. The power amplifier power supply detection module has its input terminal connected to the power amplifier power supply output terminal, and its output terminal is configured to output a first voltage signal when the power amplifier power supply output terminal outputs a power amplifier power signal, thus monitoring the power amplifier power supply status. The power amplifier input detection module includes at least one input terminal, with different input terminals connected to different power amplifier signal output terminals. Its output terminal is configured to output a second voltage signal when at least one power amplifier signal output terminal does not output a power amplifier signal, thus monitoring the power amplifier signal input status. The first transistor has its collector connected to a first power supply, and its base connected to both the output terminal of the power amplifier power supply detection module and the output terminal of the power amplifier input detection module. The first transistor is configured to output a first voltage signal at the output terminal of the power amplifier power supply detection module. The circuit is activated when the second voltage signal is output from the power amplifier input detection module. The relay's control terminal is connected to the emitter of the first transistor, its common terminal is connected to the power amplifier power output, its normally closed terminal is connected to the power amplifier load, and its normally open terminal is connected to the fault indication module. The first transistor and relay control the connection status of the power amplifier power supply and load based on the detection signal. The fault indication module's control terminal is connected to the normally open terminal of the relay. The fault indication module is configured to indicate a fault when the common terminal and normally open terminal of the relay are connected. This allows for rapid fault location, thereby enabling the detection of the power amplifier power supply and multi-channel power amplifier signal input status. This improves the stability, reliability, and maintainability of the audio power amplifier system, ensuring the normal operation and lifespan of the audio equipment. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of the structure of a power amplifier protection circuit provided in an embodiment of the present invention;

[0032] Figure 2 This is a circuit diagram of a power amplifier protection circuit provided in an embodiment of the present invention. Detailed Implementation

[0033] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, not the entire structure.

[0034] Figure 1 This is a schematic diagram of the structure of a power amplifier protection circuit provided in an embodiment of the present invention. Figure 2 This is a circuit diagram of a power amplifier protection circuit provided in an embodiment of this utility model. Figure 1and Figure 2 As shown, the power amplifier protection circuit includes:

[0035] The power amplifier power supply detection module 10 has its input terminal connected to the power amplifier power supply output terminal U+, and its output terminal is configured to output a first voltage signal when the power amplifier power supply output terminal U+ outputs a power amplifier power supply signal.

[0036] The power amplifier power supply detection module 10 can be understood as being responsible for monitoring the status of the power amplifier power supply output terminal. When the power amplifier power supply U+ outputs a normal power signal, it outputs a specific first voltage signal. The power amplifier power supply output terminal U+ can be understood as the main power supply interface of the audio power amplifier. The power amplifier power supply signal can be understood as the DC voltage signal (such as 12V, 24V, etc.) that the power amplifier power supply output terminal U+ will output when working normally. The first voltage signal can be understood as a voltage signal output by the power amplifier power supply detection module 10 after detecting that the power amplifier power supply output terminal U+ outputs a normal power amplifier power supply signal, which is used to indicate that the power amplifier power supply status is normal.

[0037] Specifically, the power amplifier power supply detection module 10 monitors the power amplifier power supply status through its internal optocouplers and other components. When the power amplifier power supply has normal output, it outputs a first voltage signal to the subsequent circuit. When the power amplifier power supply is abnormal, it interrupts the output of the first voltage signal, thereby achieving effective monitoring of the power amplifier power supply status.

[0038] The power amplifier input detection module 20 includes at least one input terminal, different input terminals are connected to different power amplifier signal output terminals, and the output terminal is configured to output a second voltage signal when at least one power amplifier signal output terminal does not output a power amplifier signal.

[0039] Among them, the power amplifier input detection module 20 can be understood as a functional module responsible for detecting the input status of multiple power amplifier signals; the power amplifier signal can be understood as the audio signal output by the pre-amplifier circuit (such as audio source device, preamplifier, etc.) in the audio power amplifier; the second voltage signal can be understood as a specific voltage signal output by the power amplifier input detection module 20 when it detects that at least one power amplifier signal output terminal does not output a power amplifier signal (i.e., an abnormal situation occurs).

[0040] Specifically, the power amplifier input detection module monitors the power amplifier signal input status through its internal switching unit 21 (such as a transistor). The control terminal of each switching unit 21 is connected to the power amplifier signal output terminal as an input terminal. When the power amplifier signal output terminal VIN1 outputs a normal power amplifier signal, the switching unit 21 is turned on, and the first voltage signal provided by the power amplifier power supply detection module 10 pulls down the base voltage of the first transistor Q1 through the switching unit 21; when VIN1 has no output or the output is abnormal, the switching unit 21 is turned off, and the base voltage of the first transistor Q1 rises, thereby realizing the monitoring of the power amplifier signal input status.

[0041] The first transistor Q1 has its collector connected to the first power supply 22 and its base connected to the output of the power amplifier power supply detection module 10 and the output of the power amplifier input detection module 20, respectively. The first transistor is configured to be cut off when the power amplifier power supply detection module outputs a first voltage signal and to be turned on when the power amplifier input detection module outputs a second voltage signal.

[0042] The first transistor Q1 can be understood as a semiconductor switch, and the working state of the relay is determined by the voltage signal input to the base; the first power supply 22 can be understood as a power supply that provides a bias voltage (such as 24V) to the collector of the first transistor Q1.

[0043] Specifically, the base of the first transistor Q1 is connected to the output of the power amplifier power supply detection module 10 and the output of the power amplifier input detection module 20, respectively. Its operating state is affected by the output signals of these two modules. When the power amplifier power supply detection module 10 outputs the first voltage signal, the first power supply 22 provides a high voltage to the base of the first transistor Q1. It then determines whether the output of the power amplifier input detection module 20 is the second voltage signal. If the power amplifier input detection module 20 outputs the second voltage signal, the base of the first transistor Q1 is grounded, and the first transistor Q1 is turned off. If the power amplifier input detection module 20 does not output the second voltage signal, the base of the first transistor Q1 is disconnected from the ground terminal, the first transistor Q1 is turned on, and the first power supply 22 supplies power to the relay 40 through the first transistor Q1.

[0044] Relay 40 has its control terminal connected to the emitter of the first transistor Q1, its common terminal connected to the power amplifier power output terminal U+, its normally closed terminal connected to the power amplifier load U+OUT, and its normally open terminal connected to the fault indication module 50.

[0045] Among them, relay 40 can be understood as an automatic switch controlled by the electrical signal of the control terminal; the common terminal can be understood as an input terminal of the relay. When the relay is not energized, the common terminal is connected to the normally closed terminal; when the relay is energized, the common terminal is connected to the normally open terminal; the power amplifier load U+OUT can be understood as the part of the load connection terminal that the power amplifier circuit obtains positive voltage power supply; the fault indication module 50 can be understood as a functional module used to indicate the fault status of the power amplifier circuit.

[0046] Specifically, when transistor Q1 is cut off, there is no current input to the control terminal of relay 40, and the common terminal of the relay is connected to the normally closed terminal. At this time, the power amplifier output terminal U+ is connected to the power amplifier load U+OUT through the common terminal and normally closed terminal of the relay. The power amplifier power supply provides power to the load, enabling the power amplifier load to work normally, such as a speaker playing sound normally. When the power amplifier input detection module detects that at least one power amplifier signal output terminal is not outputting a power amplifier signal, it will output a second voltage signal, turning on transistor Q1. At this time, current is output from the emitter of transistor Q1 to the control terminal of relay 40. After receiving the control signal, the relay's internal contacts switch, disconnecting the common terminal from the normally closed terminal and connecting it to the normally open terminal. The connection between the power amplifier output terminal U+ and the power amplifier load U+OUT is broken, protecting the power amplifier load (such as a speaker) from possible abnormal power amplifier signals. At the same time, the common terminal is connected to the normally open terminal, and the power amplifier output terminal U+ is connected to the fault indication module 50.

[0047] The fault indication module 50 is connected to the normally open terminal of the relay 40 at its control terminal. The fault indication module 50 is configured to indicate a fault when the common terminal and the normally open terminal of the relay are connected.

[0048] Specifically, when the relay receives a control signal, its internal contacts switch, disconnecting the common terminal from the normally closed terminal and connecting it to the normally open terminal. With the common terminal connected to the normally open terminal, the power amplifier output terminal U+ is connected to the fault indication module 50, causing the corresponding indicator light on the fault indication module 50 to illuminate, indicating a fault in the indication circuit.

[0049] This utility model provides a power amplifier protection circuit, including: a power amplifier power supply detection module, a power amplifier input detection module, a first transistor, a relay, and a fault indication module. The power amplifier power supply detection module has its input terminal connected to the power amplifier power supply output terminal, and its output terminal is configured to output a first voltage signal when the power amplifier power supply output terminal outputs a power amplifier power signal, thus monitoring the power amplifier power supply status. The power amplifier input detection module includes at least one input terminal, with different input terminals connected to different power amplifier signal output terminals. Its output terminal is configured to output a second voltage signal when at least one power amplifier signal output terminal does not output a power amplifier signal, thus monitoring the power amplifier signal input status. The first transistor has its collector connected to a first power supply, and its base connected to both the output terminal of the power amplifier power supply detection module and the output terminal of the power amplifier input detection module. The first transistor is configured to output a first voltage signal at the output terminal of the power amplifier power supply detection module. The circuit is activated when the second voltage signal is output from the power amplifier input detection module. The relay's control terminal is connected to the emitter of the first transistor, its common terminal is connected to the power amplifier power output, its normally closed terminal is connected to the power amplifier load, and its normally open terminal is connected to the fault indication module. The first transistor and relay control the connection status of the power amplifier power supply and load based on the detection signal. The fault indication module's control terminal is connected to the normally open terminal of the relay. The fault indication module is configured to indicate a fault when the common terminal and normally open terminal of the relay are connected. This allows for rapid fault location, thereby enabling the detection of the power amplifier power supply and multi-channel power amplifier signal input status. This improves the stability, reliability, and maintainability of the audio power amplifier system, ensuring the normal operation and lifespan of the audio equipment.

[0050] Optionally, the power amplifier power detection module includes an optocoupler H1, which includes a first terminal 11, a second terminal 12, a third terminal 13, and a fourth terminal 14.

[0051] The first terminal 11 is connected to the power amplifier power output terminal U+; the second terminal 12 is connected to the ground terminal; the fourth terminal 14 is connected to the first power supply 22; the fourth terminal 13 is connected to the base of the first transistor Q1; the third terminal 13 outputs the first power supply voltage when the power amplifier power output terminal U+ outputs the power amplifier power signal.

[0052] Among them, optocoupler H1 is a semiconductor device that converts electrical signals into optical signals and then converts optical signals back into electrical signals; the first terminal 11 and the second terminal 12 can be understood as the two connection terminals of the light-emitting diode inside optocoupler H1; the third terminal 13 and the fourth terminal 14 can be understood as the two connection terminals of the photodiode inside optocoupler H1.

[0053] Specifically, the power amplifier power supply output terminal U+ is input through the first terminal 11 of the optocoupler H1, passes through the light-emitting diode, and is output through the second terminal 12. The first power supply 22 is input through the third terminal 13, passes through the photodiode (or phototransistor or other optoelectronic device), and is output through the fourth terminal 14. When the power amplifier power supply output terminal U+ is outputting normally, the light-emitting diode illuminates the photodiode, and the signal is transmitted through optical coupling. Electrically, the input and output circuits are isolated, effectively preventing interference transmission between circuits.

[0054] Optionally, the power amplifier power detection module 10 also includes a first light-emitting diode LED3, a first resistor R4, a second resistor R3, a first capacitor C1, and a first diode D1;

[0055] The first resistor R4 is located between the fourth terminal 14 and the first power supply 22; the second resistor R3 is located between the power amplifier output terminal U+ and the first terminal 11; the first light-emitting diode LED3 and the first diode D1 are located between the second terminal 12 and the ground terminal; and the first capacitor C1 is located between the first terminal 11 and the second terminal 12.

[0056] Among them, the first resistor R4 is used to reduce the input voltage of the first power supply 22, so that the base voltage of the first transistor Q1 is lower than the collector voltage; the second resistor R3 is used to limit the current flowing through the circuit and protect the circuit from damage by excessive current; the first light-emitting diode LED3 is used to indicate that the power amplifier power supply output terminal U+ is working properly; the first diode D1 protects the optocoupler H1 and prevents the light-emitting diode from being damaged by reverse voltage pulses; the first capacitor C1 is used to stabilize the input voltage of the power amplifier power supply and reduce voltage fluctuations.

[0057] Specifically, when the power amplifier output terminal U+ outputs a normal power amplifier power signal, the current first passes through the second resistor R3 for current limiting before entering the first terminal 11 of the optocoupler H1, causing the internal LED of the optocoupler H1 to light up. The first resistor R4 limits the current flowing from the first power supply 22 to the fourth terminal 14 of the optocoupler and adjusts the operating voltage of the internal photodiode of the optocoupler. At this time, the first LED3 lights up under the action of the current, indicating that the power amplifier output is normal. The first capacitor C1 stabilizes the voltage at the control terminal of the optocoupler, reduces voltage fluctuations, and ensures stable operation of the LED. The first diode D1 protects the optocoupler from damage by reverse current. Under the action of the LED, the third terminal 13 of the optocoupler H1 outputs a first voltage signal and transmits it to the base of the first transistor Q1.

[0058] Optionally, the power amplifier input detection module 20 includes at least one switching unit 21, which is connected in series between the base of the first transistor Q1 and the ground terminal;

[0059] The control terminal of the switch unit 21 serves as the input terminal of the power amplifier input detection module 20 and is connected to the power amplifier signal output terminal VIN1. The switch unit 21 is turned on when the control terminal receives the power amplifier signal output from the power amplifier signal output terminal VIN1, and turned off when the control terminal does not receive the power amplifier signal output from the power amplifier signal output terminal VIN1.

[0060] Among them, the switching unit 21 can be understood as an electronic switch (such as a transistor) controlled by the power amplifier signal.

[0061] Specifically, when the power amplifier signal output terminal VIN1 outputs a normal power amplifier signal, the switching unit 21 is turned on. When the switching unit 21 is turned on, the output terminal of the optocoupler H1 is grounded. Conversely, when any power amplifier signal output terminal VIN1 has no signal output or the output is abnormal, its corresponding switching unit 21 is turned off, the voltage at the output terminal of the optocoupler H1 is no longer pulled low, and the second voltage signal (high voltage signal), the first transistor, and the relay are turned on.

[0062] Optionally, the switching unit 21 includes a second transistor Q2, a third resistor R6, and a second diode D3;

[0063] The power amplifier signal output terminal VIN1 is connected to the control terminal of the switching unit through the second diode Q2 and the third resistor R6 connected in series.

[0064] Among them, the second transistor Q2 is used to control the on and off of the circuit according to the power amplifier signal input status; the third resistor R6 is used to limit the current flowing through the circuit and protect the circuit from damage by excessive current; the second diode D3 is used to prevent reverse current from affecting the preceding circuit.

[0065] Specifically, when the power amplifier signal output terminal VIN1 outputs a normal power amplifier signal, the signal travels along the forward conduction direction of the second diode D3, controlling the second transistor Q2 to conduct through the third resistor R6. At this time, the switching unit 21 is turned on, grounding the output terminal of the optocoupler H1, and the first transistor Q1 is turned off. When the power amplifier signal output terminal VIN1 has no signal output or the output is abnormal, the base of the second transistor Q2 has no input, the second transistor Q2 is turned off, the switching unit 21 is turned off, the output terminal of the optocoupler H1 is connected to the first transistor Q1, the first transistor Q1 conducts, and the relay 40 is activated.

[0066] Optionally, the power amplifier input detection module 20 also includes at least one output status indicator unit 30, which is the same number as the switching unit 21. The output status indicator units are connected in series between the power amplifier signal output terminal and the ground terminal of each switching unit.

[0067] The output status indication unit 30 is configured to indicate when the power amplifier signal is output at the power amplifier signal output terminal VIN1.

[0068] The output status indicator unit 30 is used to intuitively display the working status of each power amplifier signal output terminal.

[0069] Specifically, the power amplifier signal output terminal VIN1 is also used to supply power to the output status indicator unit 30. When the power amplifier signal output terminal VIN1 outputs the power amplifier signal normally, the indicator light in the output status indicator unit 30 lights up, indicating that the power amplifier signal output terminal VIN1 is outputting normally.

[0070] Optionally, the output status indicator unit 30 includes a fourth resistor R10 and a second light-emitting diode LED4; the fourth resistor R10 and the second light-emitting diode LED4 are connected in series between the power amplifier signal output terminal VIN1 and the ground terminal.

[0071] The fourth resistor R10 is used to limit the current flowing through the output status indicator unit 30 and protect the status indicator unit 30 from damage by excessive current; the second light-emitting diode LED4 is used to indicate that the power amplifier signal output terminal VIN1 is output normally.

[0072] Specifically, the current output from the power amplifier signal output terminal VIN1 is also grounded through another branch via the fourth resistor R10 and the second light-emitting diode LED4. When the power amplifier signal output terminal VIN1 has no signal output or an abnormal output, the second light-emitting diode LED4 is open-circuited and does not light up, indicating a fault in the power amplifier signal output of that channel. In a system with multiple power amplifier signal output terminals, each output status indicator unit 30 corresponds to a different power amplifier signal output terminal VIN1 (VIN2), and they operate independently without interfering with each other. By observing the on / off status of the light-emitting diodes in each output status indicator unit 30, it is possible to quickly determine which one or more power amplifier signal outputs have a problem, thereby enabling targeted troubleshooting and repair.

[0073] Optionally, the fault indication module 50 includes a first fault indication unit 51 and a second fault indication unit 52, the power amplifier power output terminal includes a first power amplifier power output terminal U+ and a second power amplifier power output terminal U-, and the relay 40 includes a first common terminal 41, a second common terminal 42, a first normally open terminal 43 and a second normally open terminal 44.

[0074] The first common terminal 41 is connected to the first power amplifier power output terminal U+, and the second common terminal 42 is connected to the second power amplifier power output terminal U-; the first fault indication unit 51 is connected between the first normally open terminal 43 and the ground terminal, and the second fault indication unit 52 is connected between the second normally open terminal 44 and the ground terminal.

[0075] The first fault indication unit 51 is configured to indicate a fault when the first common terminal 41 and the first normally open terminal 43 are connected, and the second fault indication unit 52 is configured to indicate a fault when the first common terminal 41 and the first normally open terminal 43 are connected.

[0076] The first fault indication unit 51, the first power amplifier power output terminal U+, the first common terminal 41, and the first normally open terminal 43 form a control loop controlled by a relay. The second fault indication unit 52, the second power amplifier power output terminal U-, the second common terminal 42, and the second normally open terminal 44 form another control loop controlled by a relay. The two control loops are identical in control logic, corresponding to two branches with voltage signals U+ and U-, respectively. The first fault indication unit 51 and the second fault indication unit 52 can be understood as modules containing indicator elements such as LEDs. When the corresponding common terminal (first common terminal 41 and second common terminal 42) and normally open terminal (first normally open terminal 43 and second normally open terminal 44) of the relay 40 are connected, the LED lights up or generates other indicator signals, thereby informing the user or maintenance personnel whether the fault is related to the first power amplifier power output terminal U+ (first fault indication unit 51) or the second power amplifier power output terminal U- (second fault indication unit 52); the first power amplifier power output terminal U+ and... The second power amplifier output terminal U- can be understood as two different output interfaces that provide power to the load (such as a speaker) by the power amplifier system; the first common terminal 41 and the second common terminal 42 can be understood as common points used to switch between the corresponding normally closed terminal and normally open terminal (first normally open terminal 43 and second normally open terminal 44) of the relay 40. Under normal working conditions, the common terminal is connected to the normally closed terminal, and after the relay 40 is working, the common terminal is connected to the normally open terminal; the first normally open terminal 43 and the second normally open terminal 44 can be understood as the endpoints of the relay 40 that connect to the first common terminal 41 and the second common terminal 42 when a control signal is received.

[0077] Specifically, under normal operating conditions, the first common terminal 41 of relay 40 is connected to the first power amplifier power output terminal U+, and the second common terminal 42 is connected to the second power amplifier power output terminal U-. These terminals are also connected to their corresponding normally closed terminals, ensuring the power amplifier power supply normally powers the load. At this time, the first fault indication unit 51 and the second fault indication unit 52 are not connected to the circuit and do not operate. When the power amplifier input detection module 20 detects that at least one power amplifier signal output terminal VIN1 is not outputting a power amplifier signal (i.e., a fault has occurred), it outputs a second voltage signal, causing the first transistor Q1 to conduct. After the first transistor Q1 conducts, its emitter outputs a control signal to the control terminal of relay 40. Upon receiving the control signal, the relay connects its first common terminal 41 to the first normally open terminal 43 and its second common terminal 42 to the second normally open terminal 44, indicating a fault in the part related to the first power amplifier power output terminal U+.

[0078] Similarly, for the second fault indication unit 52, when the second common terminal 42 and the second normally open terminal 44 are connected, it indicates that a fault has occurred in the part related to the power output terminal U- of the second power amplifier.

[0079] This utility model embodiment uses the first fault indication unit 51 and the second fault indication unit 52 to indicate whether the problem is related to the first power amplifier power output terminal U+ or the second power amplifier power output terminal U- when a fault occurs in the power amplifier circuit. This makes it easier for maintenance personnel to quickly locate the source of the fault and carry out targeted repairs, thereby improving the maintainability and reliability of audio equipment.

[0080] Optionally, the first fault indication unit 51 includes a fifth resistor R5, a sixth resistor R2 and a third light-emitting diode LED1. The first normally open terminal 43 is connected to the ground terminal through the fifth resistor R5. The first normally open terminal 43 is also connected to the ground terminal through the third light-emitting diode LED1 and the sixth resistor R2 connected in series.

[0081] The second fault indication unit 52 includes a seventh resistor R7, an eighth resistor R8, and a fourth light-emitting diode LED2. The second normally open terminal 44 is connected to the ground terminal through the seventh resistor R7. The second normally open terminal 44 is also connected to the ground terminal through the fourth light-emitting diode LED2 and the eighth resistor R8 connected in series.

[0082] Among them, the fifth resistor R5 and the seventh resistor R7 are used to prevent excessive current from damaging the LED and other components; the sixth resistor R2 and the eighth resistor R8 are used to further adjust the current through the LED so that the LED can emit light stably under the appropriate current; the third LED LED1 and the fourth LED LED2 are used to indicate the fault status.

[0083] Specifically, under normal operating conditions, the first common terminal 41 of relay 40 is connected to the first power amplifier power output terminal U+, and the second common terminal 42 is connected to the second power amplifier power output terminal U-. These terminals are also connected to their corresponding normally closed terminals, ensuring the power amplifier power supply normally supplies power to the load. At this time, the first fault indication unit 51 and the second fault indication unit 52 are not connected to the circuit and do not operate. When the power amplifier input detection module 20 detects that at least one power amplifier signal output terminal VIN1 is not outputting a power amplifier signal (i.e., a fault has occurred), it outputs a second voltage signal, causing the first transistor Q1 to conduct. After the first transistor Q1 conducts, its emitter outputs a control signal to the control terminal of relay 40. Upon receiving the control signal, the relay connects its first common terminal 41 to the first normally open terminal 43, and its second common terminal 42 to the second normally open terminal 44. The first fault indication unit 51, connected to the first normally open terminal 43, is connected to the ground terminal through the fifth resistor R5, and simultaneously connected to the ground terminal through the third light-emitting diode LED1 and the sixth resistor R2 connected in series. Current flows from the first power amplifier power output terminal U+ through the first common terminal 41 and the first normally open terminal 43, and then through the fifth resistor R5 and the third light-emitting diode LED1 and the sixth resistor R2 connected in series to the ground terminal. The third light-emitting diode LED1 lights up under the action of current, indicating that there is a fault in the part related to the first power amplifier power output terminal U+.

[0084] Similarly, for the second fault indication unit 52, when the second common terminal 42 and the second normally open terminal 44 are connected, current flows from the second power amplifier power output terminal U- through the second common terminal 42 and the second normally open terminal 44, and through the seventh resistor R7 and the fourth light-emitting diode LED2 connected in series. The fourth light-emitting diode LED2 lights up under the action of the current, indicating that a fault has occurred in the part related to the second power amplifier power output terminal U-.

[0085] This utility model embodiment uses the third light-emitting diode LED1 in the first fault indication unit 51 and the fourth light-emitting diode LED2 in the second fault indication unit 52 to indicate whether a fault has occurred at the first power amplifier power output terminal U+ and the second power amplifier power output terminal U-, which facilitates maintenance personnel to quickly locate the source of the fault and carry out targeted repairs, thereby improving the maintainability and reliability of audio equipment.

[0086] Optionally, the first fault indication unit also includes a second capacitor C2, which is connected to the first power amplifier power output terminal U+.

[0087] The second fault indication unit also includes a third capacitor C3, which is connected to the second power amplifier power output terminal U-.

[0088] The second capacitor C2 is used to achieve the on / off gradient effect of the third light-emitting diode LED1, and also has certain voltage stabilization and anti-interference functions; the third capacitor C3 is used to achieve the on / off gradient effect of the fourth light-emitting diode LED2, and also has certain voltage stabilization and anti-interference functions.

[0089] Specifically, when the first power amplifier power output terminal U+ starts supplying power to the first fault indication unit 51, current charges the second capacitor C2. Since the voltage across the capacitor cannot change abruptly, the initial charging current is large. As the capacitor charges, the voltage across the capacitor gradually increases, and the charging current gradually decreases. During this process, the current through the third light-emitting diode LED1 also gradually changes, causing the brightness of LED1 to gradually increase from dark to bright, achieving a gradual on / off effect. When the second capacitor C2 is fully charged, the current reaches a stable state, and the third light-emitting diode LED1 maintains a stable brightness, continuously indicating the fault status. When the first power amplifier power output terminal U+ stops supplying power to the first fault indication unit 51, the second capacitor C2 supplies power to the third light-emitting diode LED1, and the brightness of the third light-emitting diode LED1 gradually decreases from bright to dark, achieving a gradual on / off effect. Similarly, for the second fault indication unit 52, when the power supply at the second power amplifier output terminal U- changes, the charging and discharging process of the third capacitor C3 affects the brightness of the fourth light-emitting diode LED2 to achieve a gradual on-off effect, ensuring the visibility of the fault indication, and also playing the roles of current limiting, voltage stabilization, and anti-interference, further improving the overall stability and reliability of the circuit.

[0090] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments. Many other equivalent embodiments may be included without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A power amplifier protection circuit, characterized in that, include: The power amplifier power supply detection module has an input terminal connected to the power amplifier power supply output terminal, and the output terminal is configured to output a first voltage signal when the power amplifier power supply output terminal outputs a power amplifier power supply signal. A power amplifier input detection module includes at least one input terminal, different input terminals being connected to different power amplifier signal output terminals, and the output terminal being configured to output a second voltage signal when at least one power amplifier signal output terminal does not output a power amplifier signal; The first transistor has its collector connected to the first power supply and its base connected to the output terminal of the power amplifier power supply detection module and the output terminal of the power amplifier input detection module, respectively. The first transistor is configured to be cut off when the first voltage signal is output at the output terminal of the power amplifier power supply detection module and to be turned on when the second voltage signal is output at the output terminal of the power amplifier input detection module. The relay has its control terminal connected to the emitter of the first transistor, its common terminal connected to the power amplifier power output terminal, its normally closed terminal connected to the power amplifier load, and its normally open terminal connected to the fault indication module. The fault indication module has its control terminal connected to the normally open terminal of the relay. The fault indication module is configured to indicate a fault when the common terminal and the normally open terminal of the relay are connected.

2. The power amplifier protection circuit according to claim 1, characterized in that, The power amplifier power supply detection module includes an optocoupler, which includes a first terminal, a second terminal, a third terminal, and a fourth terminal. The first terminal is connected to the power amplifier power output terminal; the second terminal is connected to the ground terminal; the fourth terminal is connected to the first power supply; the third terminal is connected to the base of the first transistor; and the third terminal outputs the first power supply voltage when the power amplifier power output terminal outputs the power amplifier power signal.

3. The power amplifier protection circuit according to claim 2, characterized in that, The power amplifier power supply detection module also includes a first light-emitting diode, a first resistor, a second resistor, a first capacitor, and a first diode; The first resistor is disposed between the fourth terminal and the first power supply; the second resistor is disposed between the power amplifier output terminal and the first terminal; the first light-emitting diode and the first diode are disposed between the second terminal and the ground terminal; the first capacitor is disposed between the first terminal and the second terminal.

4. The power amplifier protection circuit according to claim 1, characterized in that, The power amplifier input detection module includes at least one switching unit, which is connected in series between the base of the first transistor and the ground terminal. The control terminal of the switching unit serves as the input terminal of the power amplifier input detection module and is connected to the power amplifier signal output terminal. The switching unit is turned on when the control terminal receives the power amplifier signal output from the power amplifier signal output terminal, and turned off when the control terminal does not receive the power amplifier signal output from the power amplifier signal output terminal.

5. The power amplifier protection circuit according to claim 4, characterized in that, The switching unit includes a second transistor, a third resistor, and a second diode; The power amplifier signal output terminal is connected to the control terminal of the switching unit through a second diode and a third resistor connected in series.

6. The power amplifier protection circuit according to claim 4, characterized in that, The power amplifier input detection module also includes at least one output status indicator unit, which is the same number as the switching units. The output status indicator units are connected in series between the power amplifier signal output terminal and the ground terminal corresponding to each of the switching units. The output status indication unit is configured to indicate when the power amplifier signal is output at the power amplifier signal output terminal.

7. The power amplifier protection circuit according to claim 6, characterized in that, The output status indicator unit includes a fourth resistor and a second light-emitting diode; the fourth resistor and the second light-emitting diode are connected in series between the power amplifier signal output terminal and the ground terminal.

8. The power amplifier protection circuit according to claim 1, characterized in that, The fault indication module includes a first fault indication unit and a second fault indication unit; the power amplifier power output terminal includes a first power amplifier power output terminal and a second power amplifier power output terminal; and the relay includes a first common terminal, a second common terminal, a first normally open terminal and a second normally open terminal. The first common terminal is connected to the power output terminal of the first power amplifier, and the second common terminal is connected to the power output terminal of the second power amplifier. The first fault indication unit is connected between the first normally open terminal and the ground terminal, and the second fault indication unit is connected between the second normally open terminal and the ground terminal; The first fault indication unit is configured to indicate a fault when the first common terminal and the first normally open terminal are connected, and the second fault indication unit is configured to indicate a fault when the first common terminal and the first normally open terminal are connected.

9. The power amplifier protection circuit according to claim 8, characterized in that, The first fault indication unit includes a fifth resistor, a sixth resistor, and a third light-emitting diode. The first normally open terminal is connected to the ground terminal through the fifth resistor; the first normally open terminal is also connected to the ground terminal through the third light-emitting diode and the sixth resistor connected in series. The second fault indication unit includes a seventh resistor, an eighth resistor, and a fourth light-emitting diode. The second normally open terminal is connected to the ground terminal through the seventh resistor; the second normally open terminal is also connected to the ground terminal through the fourth light-emitting diode and the eighth resistor connected in series.

10. The power amplifier protection circuit according to claim 8, characterized in that, The first fault indication unit further includes a second capacitor, which is connected to the power output terminal of the first power amplifier. The second fault indication unit also includes a third capacitor, which is connected to the power output terminal of the second power amplifier.

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