Protection circuit of audio equipment and audio equipment

Abstract

The utility model relates to the technical field of audio equipment, and discloses a protection circuit of audio equipment and the audio equipment, and the protection circuit of the audio equipment comprises a first resistor, a second resistor, a voltage division protection circuit and an overcurrent and overvoltage protection circuit. One end of the first resistor is connected with a first input end of a differential signal, and the other end of the first resistor is connected with one end of the voltage-dividing protection circuit; one end of the second resistor is connected with a second input end of the differential signal, and the other end of the second resistor is connected with the other end of the voltage division protection circuit; the voltage division protection circuit is used for controlling the voltage difference between the first input end and the second input end within a preset voltage range; and the overcurrent and overvoltage protection circuit is used for shunting overvoltage to the ground when the voltage difference between the two ends of the voltage division protection circuit is greater than a preset voltage difference, and / or shunting overcurrent to the ground when the current between the two ends of the voltage division protection circuit is greater than a preset current. According to the utility model, the current and voltage on the signal line can be controlled within a safe range.

Description

Technical Field

[0001] The utility model relates to the technical field of audio equipment, in particular to a protection circuit of audio equipment and the audio equipment. Background Art

[0002] Audio equipment is a crucial tool for teachers in teaching settings. It processes and amplifies audio signals, including student speech, teacher lectures, and audio played by multimedia devices, ensuring clear transmission to every student and teacher in the classroom, enhancing teaching effectiveness. Audio equipment typically collects audio signals through pickup devices such as phantom-powered microphones. Therefore, audio equipment has multiple phantom power ports, which can be connected to phantom-powered microphones using a tip-ring-sleeve (TRS) connector.

[0003] When deploying audio equipment in classrooms and other settings, commissioning engineers often need to plug and unplug phantom-powered microphones. If phantom power is already enabled on the signal line, plugging or removing the phantom-powered microphone from a TRS connector can cause the microphone's end to contact the grounding point on the TRS connector sleeve, potentially causing a brief short circuit or current spike, potentially damaging circuits in the audio equipment (such as op amps). Utility Model Content

[0004] In view of this, the present invention provides a protection circuit for an audio device and the audio device, so as to avoid the problem of circuit damage caused by a short circuit.

[0005] In a first aspect, the present invention provides a protection circuit for an audio device, which includes a first resistor, a second resistor, a voltage divider protection circuit, and an overcurrent and overvoltage protection circuit; one end of the first resistor is connected to a first input end of a differential signal and a first output end of a phantom power circuit, and the other end of the first resistor is connected to one end of the voltage divider protection circuit; one end of the second resistor is connected to a second input end of the differential signal and a second output end of the phantom power circuit, and the other end of the second resistor is connected to the other end of the voltage divider protection circuit; the voltage divider protection circuit is also grounded, and is used to control the voltage difference between the first input end and the second input end within a preset voltage range; one end of the overcurrent and overvoltage protection circuit is connected to one end of the voltage divider protection circuit and the other end of the first resistor, and the other end of the overcurrent and overvoltage protection circuit is connected to the other end of the voltage divider protection circuit and the other end of the second resistor, and both ends of the overcurrent and overvoltage protection circuit are also connected to an amplifier integrated circuit; the overcurrent and overvoltage protection circuit is also grounded, and is used to shunt overvoltage to ground when the voltage difference between both ends of the voltage divider protection circuit is greater than the preset voltage difference, and / or to shunt overcurrent to ground when the current at both ends of the voltage divider protection circuit is greater than the preset current.

[0006] The protection circuit for an audio device provided in the present application, through the cooperation of a first resistor, a second resistor, a voltage divider protection circuit, and an overcurrent and overvoltage protection circuit arranged between a phantom power circuit and an amplifier integrated circuit, can shunt the current or voltage to ground when a high current or voltage appears on a signal line, thereby controlling the current and voltage on the signal line within a safe range, protecting the subsequent circuits in the audio device, and improving the safety and stability of the audio device.

[0007] In an optional embodiment, the voltage divider protection circuit includes a third resistor, a fourth resistor, a first bidirectional transient voltage suppressor diode and a second bidirectional transient voltage suppressor diode; one end of the third resistor is connected to the other end of the first resistor and one end of the first bidirectional transient voltage suppressor diode, and one end of the fourth resistor is connected to the other end of the second resistor and one end of the second bidirectional transient voltage suppressor diode; the other end of the third resistor and the other end of the fourth resistor are both grounded, and the other end of the first bidirectional transient voltage suppressor diode and the other end of the second bidirectional transient voltage suppressor diode are both grounded.

[0008] In this embodiment, the third resistor and the fourth resistor form a resistor voltage divider network, which can make the voltage of the differential signal reach a voltage range suitable for processing by the subsequent circuit (such as an overcurrent and overvoltage protection circuit), thereby preventing excessive input voltage from damaging the subsequent circuit.

[0009] In an optional embodiment, the overcurrent and overvoltage protection circuit includes a first Schottky diode, a second Schottky diode, a third Schottky diode, a fourth Schottky diode, a first unidirectional transient voltage suppression diode, a second unidirectional transient voltage suppression diode, a fifth resistor and a sixth resistor; the anode of the first Schottky diode is connected to the other end of the first resistor, one end of the voltage divider protection circuit and the cathode of the third Schottky diode, and the anode of the second Schottky diode is connected to the other end of the second resistor, the other end of the voltage divider protection circuit and the cathode of the fourth Schottky diode; the cathode of the first Schottky diode and the cathode of the second Schottky diode are both connected to one end of the fifth resistor and the cathode of the first unidirectional transient voltage suppression diode, and the anode of the third Schottky diode and the anode of the fourth Schottky diode are both connected to one end of the sixth resistor and the anode of the second unidirectional transient voltage suppression diode; the other end of the fifth resistor is connected to the positive electrode of the first voltage source, the other end of the sixth resistor is connected to the negative electrode of the first voltage source, and the anode of the first unidirectional transient voltage suppression diode and the cathode of the second unidirectional transient voltage suppression diode are both grounded.

[0010] In this embodiment, the Schottky diode has a relatively small junction capacitance, and the Schottky diode bridge can reduce the distortion of the differential signal. Furthermore, when a transient voltage or current exists at the two input terminals of the differential signal, the Schottky diode bridge can direct the voltage or current to the first unidirectional transient voltage suppression diode and the second unidirectional transient voltage suppression diode, thereby controlling the voltage or current of the overcurrent and overvoltage protection circuit within a safe range.

[0011] In an optional embodiment, the protection circuit of the audio device also includes a filtering circuit; one end of the filtering circuit is connected to the first input end of the differential signal, the other end of the filtering circuit is connected to the second input end of the differential signal, and the filtering circuit is also grounded to filter out interference signals in the differential signal.

[0012] In an optional embodiment, the filtering circuit includes a first capacitor, a second capacitor and a third capacitor; one end of the first capacitor is grounded, the other end of the first capacitor is connected to one end of the second capacitor and one end of the third capacitor, the other end of the second capacitor is connected to the first input end, and the other end of the third capacitor is connected to the second input end.

[0013] In an optional embodiment, the protection circuit of the audio device also includes a first DC blocking capacitor and a second DC blocking capacitor; one end of the first DC blocking capacitor is connected to the first input terminal, the other end of the first DC blocking capacitor is connected to one end of the first resistor, one end of the second DC blocking capacitor is connected to the second input terminal, and the other end of the second DC blocking capacitor is connected to one end of the second resistor.

[0014] In this embodiment, by providing DC blocking capacitors between the two output terminals of the phantom power circuit and the amplifier integrated circuit, the DC component of the audio signal can be prevented from entering the amplifier integrated circuit while the audio signal is transmitted to the amplifier integrated circuit for amplification, thereby preventing the operating point of the amplifier integrated circuit from being affected.

[0015] In a second aspect, the present invention provides an audio device, which includes a phantom power supply circuit and a protection circuit of the audio device according to the first aspect or any corresponding embodiment thereof.

[0016] In an optional embodiment, the audio device also includes a phantom power control circuit and a soft start circuit, and the initial state of the phantom power circuit is configured to be an off state; the input end of the phantom power control circuit is connected to the control chip, the output end of the phantom power control circuit is connected to the input end of the soft start circuit, and the output end of the soft start circuit is connected to the phantom power circuit; the phantom power control circuit is used to input a conduction signal to the soft start circuit when the control chip outputs a preset control signal, and after receiving the conduction signal, the soft start circuit puts the phantom power circuit into a conduction state after a preset time.

[0017] In this embodiment, the phantom power circuit is initially configured to be off, preventing damage to external devices with built-in phantom power when connected to the audio system. Furthermore, a soft-start circuit increases the phantom power circuit's on-time, preventing excessive current surges at the moment the power is turned on, thus protecting other components in the circuit.

[0018] In an optional embodiment, the slow start circuit includes a seventh resistor, an eighth resistor, a third DC blocking capacitor, a diode and a first switching tube; one end of the seventh resistor and one end of the eighth resistor are both connected to the output end of the phantom power control circuit, the other end of the seventh resistor is connected to a connection end of the first switching tube, the other end of the eighth resistor is connected to the control end of the first switching tube, and the other connection end of the first switching tube is connected to the phantom power circuit; one end of the third DC blocking capacitor is connected to the other end of the seventh resistor and a connection end of the first switching tube, and one end of the third DC blocking capacitor is connected to the other end of the eighth resistor and the control end of the first switching tube; the cathode of the diode is connected to the other end of the seventh resistor and a connection end of the first switching tube, and the anode of the diode is connected to the other end of the eighth resistor and the control end of the first switching tube.

[0019] In an optional embodiment, the phantom power control circuit includes a ninth resistor, a tenth resistor, an eleventh resistor and a second switch tube; one end of the ninth resistor is connected to the control chip, the other end of the ninth resistor is connected to one end of the tenth resistor and the control end of the second switch tube, the other end of the tenth resistor and one connection end of the second switch tube are both grounded, the other connection end of the second switch tube is connected to one end of the eleventh resistor, and the other end of the eleventh resistor is connected to the input end of the soft start circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in related technologies, the following briefly introduces the drawings required for use in the specific implementation methods or related technical descriptions. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 is a schematic diagram of the connection between an audio device and a sound pickup device according to an embodiment of the present utility model;

[0022] Figure 2 is a schematic diagram of a phantom power supply method according to an embodiment of the present utility model;

[0023] Figure 3 is a schematic diagram of a protection circuit of an audio device according to an embodiment of the present utility model;

[0024] Figure 4 is a schematic diagram of a protection circuit of another audio device according to an embodiment of the present utility model;

[0025] Figure 5 is a schematic diagram of a protection circuit of another audio device according to an embodiment of the present utility model;

[0026] Figure 6 is a schematic diagram of a circuit of an audio device according to an embodiment of the present utility model;

[0027] Figure 7 2 is a schematic diagram of a circuit of another audio device according to an embodiment of the present invention.

[0028] Figure numerals: 10, sound pickup device; 20, audio device; 21, audio input interface; 22, phantom power circuit; 23, protection circuit; 231, voltage divider protection circuit; 232, overcurrent and overvoltage protection circuit; 233, filter circuit; 24, amplifier integrated circuit; 25, phantom power control circuit; 26, soft start circuit; 30, control chip; 40, third-party device; 50, power supply chip. DETAILED DESCRIPTION

[0029] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of the present invention.

[0030] Phantom power is a method of powering microphones and other pickup devices through audio transmission lines. Its basic principle is to use the potential difference between the two signal lines and the ground line in a balanced transmission line to provide DC power.

[0031] Specifically, if Figure 1 As shown, the audio device 20 is provided with an audio input interface 21. A microphone or other sound pickup device 10 can be connected to the audio device 20 via an audio transmission line and the audio input interface 21. A phantom power circuit 22 within the audio device 20 provides power to the sound pickup device 10 via the audio transmission line. At the same time, the audio signal determined by the sound pickup device 10 is also transmitted to the audio device 20 via the audio transmission line so that the audio device 20 can process the audio signal. The audio transmission line can be connected to the sound pickup device 10 via an XLR-3 connector.

[0032] For example, the phantom power supply can be as follows: Figure 2 As shown, Pin 1 of the XLR-3 connector represents the ground line, Pins 2 and 3 represent the two differential signal lines, and resistors R15 and R16 are used to balance signal transmission and prevent interference. 48V indicates that the DC power supply voltage supplied to the pickup device is 48V. The resistance of the two resistors R15 and R16 can be 6.8KΩ.

[0033] When deploying audio equipment in scenarios like classrooms, the equipment installers and commissioning personnel may not be the same group. Consequently, after the audio equipment is installed, the audio signal cables may not be fully connected. Therefore, after the audio equipment is powered on, the commissioning engineer may need to repeatedly plug and unplug the microphone to debug the audio equipment. During this process, if the microphone connector contacts the sleeve of the audio input connector during plugging and unplugging, it may cause a brief short circuit or current spike, potentially damaging components in the phantom power circuit.

[0034] In view of this, the present application provides a protection circuit for an audio device. By setting a first resistor, a second resistor, a voltage divider protection circuit and an overcurrent and overvoltage protection circuit between a phantom power circuit and an amplifier integrated circuit (AMP IC), the current and voltage on the signal line can be controlled within a safe range when a higher current or voltage appears on the signal line, thereby protecting the subsequent circuits in the audio device and improving the safety of the audio device.

[0035] The protection circuit of the audio device provided by this application is described in detail below with reference to the accompanying drawings.

[0036] like Figure 3 As shown, the protection circuit 23 of the audio device includes a first resistor R1 , a second resistor R2 , a voltage divider protection circuit 231 and an overcurrent and overvoltage protection circuit 232 .

[0037] Among them, one end of the first resistor R1 is connected to the first input end of the differential signal and the first output end of the phantom power circuit 22, the other end of the first resistor R1 is connected to one end of the voltage divider protection circuit 231, one end of the second resistor R2 is connected to the second input end of the differential signal and the second output end of the phantom power circuit 22, the other end of the second resistor R2 is connected to the other end of the voltage divider protection circuit 231, and the voltage divider protection circuit 231 is also grounded, and is used to control the voltage difference between the first input end and the second input end within a preset voltage range.

[0038] Specifically, the first input terminal (MICRO+) of the differential signal can be a high-potential voltage terminal, and the second input terminal (MICRO-) of the differential signal can be a low-potential voltage terminal. The first output voltage terminal of the phantom power circuit 22 (PHANTOM_48V) can be connected to the first input terminal of the differential signal line via a twelfth resistor R12, and the second output voltage terminal of the phantom power circuit 22 (PHANTOM_48V) can be connected to the second input terminal of the differential signal line via a thirteenth resistor R13.

[0039] The first differential signal input terminal and the second differential signal input terminal can be ports corresponding to the two differential signal lines in the audio input interface 21, which are connected to the sound pickup device 10, receive the audio signal represented by the differential signal from the sound pickup device 10, and transmit power provided by the phantom power circuit 22 (PHANTOM_48V) to the sound pickup device 10. The preset voltage range is the voltage range corresponding to the normal operation of the audio device's post-stage circuit (such as the amplifier integrated circuit 24), and can be determined by the designer based on the requirements of the audio device.

[0040] The first resistor R1 and the second resistor R2 are both current-limiting resistors, which are used to limit destructive current. That is, the first resistor R1 and the second resistor R2 are used to reduce the current value in the signal line. The degree of reduction is determined based on the resistance values ​​of the first resistor R1 and the second resistor R2, and can be set by the designer according to needs.

[0041] One end of the overcurrent and overvoltage protection circuit 232 is connected to one end of the voltage divider protection circuit 231 and the other end of the first resistor R1, and the other end of the overcurrent and overvoltage protection circuit 232 is connected to the other end of the voltage divider protection circuit 231 and the other end of the second resistor R2. Both ends of the overcurrent and overvoltage protection circuit 232 are also connected to the amplifier integrated circuit 24. The overcurrent and overvoltage protection circuit 232 is grounded and is configured to shunt overvoltage to ground when the voltage difference between the two ends of the voltage divider protection circuit 231 is greater than a preset voltage difference, and / or to shunt overcurrent to ground when the current across the two ends of the voltage divider protection circuit 231 is greater than a preset current, thereby preventing the voltage and current output by the overcurrent and overvoltage protection circuit 232 from exceeding a safe range and protecting subsequent circuits.

[0042] Among them, the preset voltage difference can be the voltage corresponding to the normal operation of the subsequent circuit, the preset current can be the current corresponding to the normal operation of the subsequent circuit, the overvoltage can refer to the difference between the voltage difference and the preset voltage difference, and the overcurrent can refer to the difference between the current and the preset current.

[0043] Specifically, the current input from the two differential signal input terminals (i.e., the first input terminal and the second input terminal) flows through the current-limiting resistor and then to the voltage divider protection circuit 231. After voltage division and preliminary processing, the current continues to flow through the overcurrent protection circuit 232. If there is still a transient high voltage or high current, the overcurrent protection circuit 232 will shunt most of the voltage and current to ground. Ultimately, the processed and protected current (i.e., the processed audio signals MIC_IN+ and MIC_IN-) enters the amplifier integrated circuit 24 for further amplification.

[0044] The protection circuit for an audio device provided in the present application, through the cooperation of a first resistor, a second resistor, a voltage divider protection circuit, and an overcurrent and overvoltage protection circuit arranged between a phantom power circuit and an amplifier integrated circuit, can shunt the current or voltage to ground when a high current or voltage appears on a signal line, thereby controlling the current and voltage on the signal line within a safe range, protecting the subsequent circuits in the audio device, and improving the safety and stability of the audio device.

[0045] The present application does not limit the specific structures of the voltage divider protection circuit 231 and the overcurrent and overvoltage protection circuit 232, as long as they can complete the corresponding functions defined in the above embodiments.

[0046] For example, Figure 4As shown, the voltage divider protection circuit 231 includes a third resistor R3, a fourth resistor R4, a first bidirectional transient voltage suppressor diode D1, and a second bidirectional transient voltage suppressor diode D2.

[0047] One end of the third resistor R3 is connected to the other end of the first resistor R1 and one end of the first bidirectional transient voltage suppressor diode D1. One end of the fourth resistor R4 is connected to the other end of the second resistor R2 and one end of the second bidirectional transient voltage suppressor diode D2. The other ends of the third resistor R3 and the fourth resistor R4 are both grounded, and the other ends of the first bidirectional transient voltage suppressor diode D1 and the second bidirectional transient voltage suppressor diode D2 are both grounded.

[0048] That is, the third resistor R3 and the fourth resistor R4 are connected in series and then arranged in parallel between the two input terminals of the differential signal; the first bidirectional transient voltage suppression diode D1 and the second bidirectional transient voltage suppression diode D2 are also connected in series and then arranged in parallel between the two input terminals of the differential signal.

[0049] The third resistor R3 and the fourth resistor R4 can attenuate the input signal to a level suitable for processing. Specifically, the third resistor R3 and the fourth resistor R4 form a resistor voltage divider network, which distributes the voltage of the input differential signal between the third resistor R3 and the fourth resistor R4, so that the voltage of the differential signal reaches a voltage range suitable for processing by subsequent circuits (such as overcurrent and overvoltage protection circuits), thereby preventing excessive input voltage from damaging the subsequent circuits.

[0050] When a transient pulse higher than the normal operating voltage appears at the two input ends of the differential signal, such as electrostatic discharge (ESD), the first bidirectional transient voltage suppression (TVS) diode D1 and the second bidirectional TVS diode D2 will quickly change from a high-impedance state to a low-impedance state, shunting most of the voltage to ground, thereby keeping the output voltage after passing through the resistor divider network within a relatively stable and safe range, ensuring the normal operation and reliability of the entire circuit.

[0051] Specifically, a TVS diode is a highly effective protection device. Under normal operating conditions, it maintains a high-impedance state, virtually impacting circuit operation. However, when a transient high-voltage pulse occurs in a circuit, the TVS diode rapidly switches from a high-impedance state to a low-impedance state, shunting the overvoltage to ground and protecting subsequent circuits.

[0052] Furthermore, if Figure 4As shown, the overcurrent and overvoltage protection circuit 232 includes a first Schottky diode D3, a second Schottky diode D4, a third Schottky diode D5, a fourth Schottky diode D6, a first unidirectional transient voltage suppression diode D7, a second unidirectional transient voltage suppression diode D8, a fifth resistor R5 and a sixth resistor R6.

[0053] Among them, the anode of the first Schottky diode D3 is connected to the other end of the first resistor R1, one end of the voltage divider protection circuit 23 and the cathode of the third Schottky diode D5, and the anode of the second Schottky diode D4 is connected to the other end of the second resistor R2, the other end of the voltage divider protection circuit 23 and the cathode of the fourth Schottky diode D6.

[0054] The cathode of the first Schottky diode D3 and the cathode of the second Schottky diode D4 are both connected to one end of the fifth resistor R5 and the cathode of the first unidirectional transient voltage suppressor diode D7, and the anode of the third Schottky diode D5 and the anode of the fourth Schottky diode D6 are both connected to one end of the sixth resistor R6 and the anode of the second unidirectional transient voltage suppressor diode D8.

[0055] The other end of the fifth resistor R5 is connected to the positive electrode (VCC_+3.3V) of the first voltage source, the other end of the sixth resistor R6 is connected to the negative electrode (VCC_-3.3V) of the first voltage source, and the anode of the first unidirectional transient voltage suppressor diode D7 and the cathode of the second unidirectional transient voltage suppressor diode D8 are both grounded. The reference voltage of the first voltage source can be 3.3V.

[0056] That is, the first Schottky diode D3, the second Schottky diode D4, the third Schottky diode D5 and the fourth Schottky diode D6 form a Schottky diode bridge, which is connected to the cathode of the first unidirectional transient voltage suppressor diode D7 and the anode of the second unidirectional transient voltage suppressor diode D8 through the Schottky diode bridge.

[0057] Specifically, the Schottky diode has a small junction capacitance, and the Schottky diode bridge can reduce the distortion of the differential signal. Moreover, when a transient voltage or current exists on the two input ends of the differential signal, the Schottky diode bridge can guide the voltage or current to the TVS diode (i.e., the first unidirectional transient voltage suppression diode D7 and the second unidirectional transient voltage suppression diode D8) to control the voltage or current of the overcurrent and overvoltage protection circuit 232 within a safe range. The overvoltage and overcurrent will then flow to ground through the TVS diode, the fifth resistor R5, and the sixth resistor R6, thereby protecting the subsequent circuit.

[0058] The fifth resistor R5 and the sixth resistor R6 are bias resistors, which pre-configure the first unidirectional transient voltage suppression diode D7 and the second unidirectional transient voltage suppression diode D8 to a conductive state, so that the TVS diode can respond quickly to the protection circuit when a surge occurs.

[0059] Specifically, under normal circumstances, a micro-current flows from the first voltage source through the fifth resistor R5, the first unidirectional transient voltage suppression diode D7, the sixth resistor R6 and the second unidirectional transient voltage suppression diode D8 to the ground, causing the TVS diode to be in a pre-conduction state. When a surge occurs at the two input ends of the differential signal, the TVS diode responds quickly (i.e., it is fully in the on state) and directs the overvoltage or overcurrent to the ground.

[0060] It should be understood that a Schottky diode is a diode formed by the contact between metal and semiconductor. It is composed of a Schottky barrier formed by the contact between metal (such as aluminum, gold, etc.) and semiconductor material (such as silicon, gallium arsenide, etc.), and has a low forward voltage drop and a faster switching speed.

[0061] In some optional embodiments, such as Figure 5 As shown, the protection circuit 23 of the audio device also includes a filter circuit 233, one end of the filter circuit 233 is connected to the first input end of the differential signal, the other end of the filter circuit 233 is connected to the second input end of the differential signal, and the filter circuit 233 is also grounded for filtering out interference signals in the differential signal.

[0062] In one example, the filter circuit 233 includes a first capacitor C1, a second capacitor C2, and a third capacitor C3. One end of the first capacitor C1 is grounded, the other end of the first capacitor C1 is connected to one end of the second capacitor C2 and one end of the third capacitor C3, the other end of the second capacitor C2 is connected to the first input terminal, and the other end of the third capacitor C3 is connected to the second input terminal.

[0063] Specifically, the filtering circuit 233 further includes a fourteenth resistor R14 , one end of the fourteenth resistor R14 is connected to the other end of the second capacitor C2 , and the other end of the fourteenth resistor R14 is connected to the other end of the third capacitor C3 .

[0064] In this embodiment, the first capacitor C1 , the second capacitor C2 , and the third capacitor C3 form a T-type filter, which can effectively filter out radio frequency interference on the differential signal line and shunt current to the ground.

[0065] like Figure 5As shown, the protection circuit 23 of the audio device further includes a first DC blocking capacitor CD1 and a second DC blocking capacitor CD2. One end of the first DC blocking capacitor CD1 is connected to the first input terminal, and the other end of the first DC blocking capacitor CD1 is connected to one end of the first resistor R1. One end of the second DC blocking capacitor CD2 is connected to the second input terminal, and the other end of the second DC blocking capacitor CD2 is connected to one end of the second resistor R2.

[0066] In this embodiment, by providing DC blocking capacitors between the two output terminals of the phantom power circuit and the amplifier integrated circuit, the DC component of the audio signal can be prevented from entering the amplifier integrated circuit while the audio signal is transmitted to the amplifier integrated circuit for amplification, thereby preventing the operating point of the amplifier integrated circuit from being affected.

[0067] The present application also provides an audio device, wherein the audio device 20 includes a phantom power circuit 22 and a protection circuit 23 of the audio device provided in any of the above embodiments. Figure 6 As shown, a sound pickup device 10 such as a microphone and a third-party device 40 can be connected to a phantom power circuit 22 via an audio input interface 21 . The third-party device can be a mixing console, a personal computer (PC) or other device with audio output.

[0068] Furthermore, if Figure 6 As shown, the audio device further includes a phantom power control circuit 25 and a soft-start circuit 26. The initial state of the phantom power circuit 22 is configured to be off. The input end of the phantom power control circuit 25 is connected to the control chip 30, the output end of the phantom power control circuit 25 is connected to the input end of the soft-start circuit 26, and the output end of the soft-start circuit 26 is connected to the phantom power circuit 22.

[0069] The phantom power control circuit 25 is used to input a conduction signal to the soft start circuit 26 when the control chip 30 outputs a preset control signal. After receiving the conduction signal, the soft start circuit 26 turns on the phantom power circuit 22 after a preset time.

[0070] Among them, the control chip 30 can be a system on chip (SOC) or a microcontroller unit (MCU), etc. The control chip 30 can output a preset control signal when the user chooses to turn on the power supply function through the user interface (UI), or output a preset control signal when the connected sound pickup device is a preset sound pickup device. The preset sound pickup device can be configured by the designer.

[0071] The preset control signal (GPIO_48V_PWREN) can be a high-level signal or a low-level signal. The preset duration is a fixed value and can be determined by the designer based on experience. For example, the preset duration can be 0.5s or 1s.

[0072] Specifically, configuring the phantom power circuit 22 to be initially off prevents damage to external devices with built-in phantom power (such as desktop gooseneck microphones) when connected to audio equipment. Furthermore, by increasing the on-time of the phantom power circuit 22 through the soft-start circuit 26, excessive current surges at the moment of power-on are avoided, protecting other components in the circuit.

[0073] For example, Figure 7 As shown, the soft start circuit 26 includes a seventh resistor R7, an eighth resistor R8, a third DC blocking capacitor CD3, a diode D9 and a first switch tube Q1.

[0074] One end of the seventh resistor R7 and one end of the eighth resistor R8 are both connected to the output end of the phantom power control circuit 25, the other end of the seventh resistor R7 is connected to one connection end of the first switch tube Q1, the other end of the eighth resistor R8 is connected to the control end of the first switch tube Q1, and the other connection end of the first switch tube Q1 is connected to the phantom power circuit 22.

[0075] One end of the third DC blocking capacitor CD3 is connected to the other end of the seventh resistor R7 and one connection end of the first switching transistor Q1. One end of the third DC blocking capacitor CD3 is connected to the other end of the eighth resistor R8 and the control end of the first switching transistor Q1. The cathode of the diode D9 is connected to the other end of the seventh resistor R7 and one connection end of the first switching transistor Q1. The anode of the diode D9 is connected to the other end of the eighth resistor R8 and the control end of the first switching transistor Q1. The preset time duration may be the charging time duration of the third DC blocking capacitor CD3.

[0076] The first switch tube Q1 can be a switching device such as a Metal Oxide Semiconductor Field Effect Transistor (MOSFET) or a triode. MOSFET is referred to as MOS tube. Figure 7 The first switch tube Q1 is taken as a P-type MOS tube as an example, but the present invention is not limited thereto.

[0077] When the first switch tube Q1 is a P-type MOS tube, the control end of the first switch tube Q1 is the gate of the P-type MOS tube, one connection end of the first switch tube Q1 is the source of the P-type MOS tube, and the other connection end of the first switch tube Q1 is the drain of the P-type MOS tube.

[0078] Specifically, after receiving the on-signal, the soft-start circuit 26 charges the third DC-blocking capacitor CD3, gradually increasing the on-time of the first switch Q1 to achieve a soft start of the power supply. Furthermore, the diode D9 prevents the control and connection terminals of the first switch Q1 from being damaged by reverse bias.

[0079] Exemplarily, the soft start circuit 26 may further include a fourth capacitor C4 and a fifth capacitor C5, one end of the fourth capacitor C4 is grounded, the other end of the fourth capacitor C4 is connected to the other end of the seventh resistor R7, one end of the fifth capacitor C5 is connected to the other connection end of the first switch tube Q1, and the other end of the fifth capacitor C5 is connected to the other end of the eighth resistor R8 and the control end of the first switch tube Q1.

[0080] For example, Figure 7 As shown, the phantom power control circuit 25 includes a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a second switch tube Q2.

[0081] Among them, one end of the ninth resistor R9 is connected to the control chip 30, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10 and the control end of the second switch tube Q2, the other end of the tenth resistor R10 and one connection end of the second switch tube Q2 are both grounded, the other connection end of the second switch tube Q2 is connected to one end of the eleventh resistor R11, and the other end of the eleventh resistor R11 is connected to the input end of the soft start circuit 26.

[0082] The second switch tube Q2 can be a switching device such as a MOS tube or a triode. Figure 7 The second switch tube Q2 is taken as an N-type MOS tube as an example, but the present invention is not limited thereto.

[0083] When the second switch transistor Q2 is an N-type MOS transistor, the control terminal of the second switch transistor Q2 is the gate of the N-type MOS transistor, one connection terminal of the second switch transistor Q2 is the source of the N-type MOS transistor, and the other connection terminal of the second switch transistor Q2 is the drain of the N-type MOS transistor. In this case, the preset control signal is a high-level signal.

[0084] Specifically, in response to the user operation, the control signal (GPIO_48_PWREN) output by the control chip 30 is a high-level signal, so that the second switch tube Q2 is in a conducting state, and a conduction signal is generated to flow to the soft start circuit.

[0085] like Figure 7 As shown, a power supply chip 50 can provide a 48V DC voltage source (POWER_48V) for the phantom power circuit 22. The power supply chip 50 can be a TI voltage regulator chip TPS61390 or LM5155. The DC voltage source (POWER_48V) is connected in series with a fourth DC blocking capacitor CD4 and then to ground. The phantom power circuit 22 is connected in series with a fifth DC blocking capacitor CD5 and then to ground.

[0086] Exemplarily, the soft start circuit 26 may further include a fourth capacitor C4 and a fifth capacitor C5, one end of the fourth capacitor C4 is grounded, the other end of the fourth capacitor C4 is connected to the other end of the seventh resistor R7, one end of the fifth capacitor C5 is connected to the other connection end of the first switch tube Q1, and the other end of the fifth capacitor C5 is connected to the other end of the eighth resistor R8 and the control end of the first switch tube Q1.

[0087] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0088] In this utility model, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection, electrical connection; direct connection, or indirect connection through an intermediate medium; internal communication between two components, or interaction between two components, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on specific circumstances.

[0089] It should be understood that the various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used to implement the hardware: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0090] In the description of this specification, the description with reference to the terms "this embodiment", "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples without contradiction.

[0091] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature specified as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of this utility model, "plurality" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0092] Although the embodiments of the present invention are described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the present invention.

Claims

1. A protection circuit for an audio device, characterized in that: The protection circuit of the audio device includes a first resistor, a second resistor, a voltage divider protection circuit and an overcurrent and overvoltage protection circuit; One end of the first resistor is connected to the first input end of the differential signal and the first output end of the phantom power circuit, and the other end of the first resistor is connected to one end of the voltage divider protection circuit; One end of the second resistor is connected to the second input end of the differential signal and the second output end of the phantom power supply circuit, and the other end of the second resistor is connected to the other end of the voltage divider protection circuit; The voltage divider protection circuit is grounded and configured to control the voltage difference between the first input terminal and the second input terminal within a preset voltage range; One end of the overcurrent and overvoltage protection circuit is connected to one end of the voltage divider protection circuit and the other end of the first resistor, the other end of the overcurrent and overvoltage protection circuit is connected to the other end of the voltage divider protection circuit and the other end of the second resistor, and both ends of the overcurrent and overvoltage protection circuit are also connected to the amplifier integrated circuit; The overcurrent and overvoltage protection circuit is grounded, and is used to shunt the overvoltage to the ground when the voltage difference between the two ends of the voltage divider protection circuit is greater than a preset voltage difference, and / or to shunt the overcurrent to the ground when the current at the two ends of the voltage divider protection circuit is greater than a preset current.

2. The protection circuit of the audio device according to claim 1, characterized in that: The voltage divider protection circuit includes a third resistor, a fourth resistor, a first bidirectional transient voltage suppression diode and a second bidirectional transient voltage suppression diode; One end of the third resistor is connected to the other end of the first resistor and one end of the first bidirectional transient voltage suppressor diode, and one end of the fourth resistor is connected to the other end of the second resistor and one end of the second bidirectional transient voltage suppressor diode; The other end of the third resistor and the other end of the fourth resistor are both grounded, and the other end of the first bidirectional transient voltage suppressor diode and the other end of the second bidirectional transient voltage suppressor diode are both grounded.

3. The protection circuit of the audio device according to claim 1, characterized in that: The overcurrent and overvoltage protection circuit includes a first Schottky diode, a second Schottky diode, a third Schottky diode, a fourth Schottky diode, a first unidirectional transient voltage suppression diode, a second unidirectional transient voltage suppression diode, a fifth resistor and a sixth resistor; The anode of the first Schottky diode is connected to the other end of the first resistor, one end of the voltage divider protection circuit, and the cathode of the third Schottky diode, and the anode of the second Schottky diode is connected to the other end of the second resistor, the other end of the voltage divider protection circuit, and the cathode of the fourth Schottky diode; The cathode of the first Schottky diode and the cathode of the second Schottky diode are both connected to one end of the fifth resistor and the cathode of the first unidirectional transient voltage suppressor diode, and the anode of the third Schottky diode and the anode of the fourth Schottky diode are both connected to one end of the sixth resistor and the anode of the second unidirectional transient voltage suppressor diode; The other end of the fifth resistor is connected to the positive electrode of the first voltage source, the other end of the sixth resistor is connected to the negative electrode of the first voltage source, and the anode of the first unidirectional transient voltage suppression diode and the cathode of the second unidirectional transient voltage suppression diode are both grounded.

4. The protection circuit of the audio device according to any one of claims 1 to 3, characterized in that: The protection circuit of the audio device further includes a filter circuit; One end of the filter circuit is connected to the first input end of the differential signal, and the other end of the filter circuit is connected to the second input end of the differential signal. The filter circuit is also grounded and is used to filter out interference signals in the differential signal.

5. The protection circuit of the audio device according to claim 4, characterized in that: The filtering circuit includes a first capacitor, a second capacitor and a third capacitor; One end of the first capacitor is grounded, the other end of the first capacitor is connected to one end of the second capacitor and one end of the third capacitor, the other end of the second capacitor is connected to the first input end, and the other end of the third capacitor is connected to the second input end.

6. The protection circuit for audio equipment according to claim 4, wherein: The protection circuit of the audio device further includes a first DC blocking capacitor and a second DC blocking capacitor; One end of the first blocking capacitor is connected to the first input end, the other end of the first blocking capacitor is connected to one end of the first resistor, one end of the second blocking capacitor is connected to the second input end, and the other end of the second blocking capacitor is connected to one end of the second resistor.

7. An audio device, characterized in that The audio device includes a phantom power circuit and the protection circuit of the audio device according to any one of claims 1 to 6.

8. The audio device according to claim 7, wherein The audio device further includes a phantom power control circuit and a soft start circuit, wherein the initial state of the phantom power circuit is configured to be an off state; The input end of the phantom power control circuit is connected to the control chip, the output end of the phantom power control circuit is connected to the input end of the slow start circuit, and the output end of the slow start circuit is connected to the phantom power circuit; The phantom power control circuit is used to input a conduction signal to the soft start circuit when the control chip outputs a preset control signal. After receiving the conduction signal, the soft start circuit puts the phantom power circuit into a conduction state after a preset time.

9. The audio device according to claim 8, wherein The soft start circuit includes a seventh resistor, an eighth resistor, a third DC blocking capacitor, a diode and a first switch tube; One end of the seventh resistor and one end of the eighth resistor are both connected to the output end of the phantom power control circuit, the other end of the seventh resistor is connected to one connection end of the first switch tube, the other end of the eighth resistor is connected to the control end of the first switch tube, and the other connection end of the first switch tube is connected to the phantom power circuit; One end of the third DC blocking capacitor is connected to the other end of the seventh resistor and one connection end of the first switching tube, and one end of the third DC blocking capacitor is connected to the other end of the eighth resistor and the control end of the first switching tube; The cathode of the diode is connected to the other end of the seventh resistor and one connection end of the first switch tube, and the anode of the diode is connected to the other end of the eighth resistor and the control end of the first switch tube.

10. The audio device according to claim 8, wherein The phantom power control circuit includes a ninth resistor, a tenth resistor, an eleventh resistor and a second switch tube; One end of the ninth resistor is connected to the control chip, the other end of the ninth resistor is connected to one end of the tenth resistor and the control end of the second switch tube, the other end of the tenth resistor and one connection end of the second switch tube are both grounded, the other connection end of the second switch tube is connected to one end of the eleventh resistor, and the other end of the eleventh resistor is connected to the input end of the soft start circuit.

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