Mute circuit
By designing a mute circuit using MUTE pins and transistors, the existing mute circuit has solved the complex structure and high cost problems, and achieved simple and low-cost mute effect, and improved the overall performance of the circuit.
Patent Information
- Application Number
- CN202421874794.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-05
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-08-05
AI Technical Summary
The existing silent circuit has complex structure and high cost, and is not suitable for large-scale production and widespread applications.
A mute circuit including an op amp circuit, a control circuit and an output circuit is designed. The control circuit uses a MUTE pin and a transistor to achieve mute effect through simple control logic.
It realizes a simple structure and low cost silent effect, avoids complex control logic, and improves the overall performance and reliability of the circuit.
Smart Images
Figure CN222869029U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of circuit design, and in particular to a mute circuit. Background Art
[0002] For some audio output devices, their volume can usually be controlled or they can be put into a muted state. There are many forms of mute circuits currently applicable to audio output devices, but the circuit structure is relatively complex, resulting in high costs, which is not conducive to large-scale production and wide application. Utility Model Content
[0003] In order to solve the above technical problems, the present application provides a mute circuit with simple structure and low cost.
[0004] Specifically, the present application provides a mute circuit, including an operational amplifier circuit, a control circuit and an output circuit.
[0005] The control circuit at least includes a MUTE pin, a first transistor, a second transistor and a third transistor.
[0006] The base of the third transistor is connected to the MUTE pin, the collector of the third transistor is respectively connected to the base of the first transistor and the base of the second transistor, and the emitter of the first transistor and the emitter of the second transistor are connected to the output circuit.
[0007] Among them, the MUTE pin outputs a low level to the third transistor, driving the first transistor and the second transistor to be turned on, so as to pull the analog signal received by the operational amplifier circuit down to the ground potential, block the output circuit from outputting the analog signal, and thus achieve a mute effect.
[0008] In the above technical solution, the control circuit uses a MUTE pin and a transistor, which has a simple and intuitive structure. The three transistors are controlled by a low-level signal of a MUTE pin, which can effectively realize mute control. This structure avoids complex control logic, making circuit design and debugging relatively simple; by turning on the first transistor and the second transistor, the signal is pulled down to the ground potential, which can achieve fast and effective mute, ensuring that the signal will not leak to the output circuit in the mute state, thereby ensuring an efficient mute effect; the switching speed of the transistor is fast, and it can quickly respond to the control signal of the MUTE pin to provide a real-time mute function, and the power consumption of the transistor is low when working in the switching state, which will not have a significant impact on the overall power consumption of the system.
[0009] In addition, the circuit design has a simple structure and is easy to integrate with other circuit modules; since the connection method between the control signal (MUTE pin) and the transistor is direct and effective, the mute function can be easily implemented in various devices without complex external control logic.
[0010] Furthermore, the operational amplifier circuit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a sixth capacitor, a seventh capacitor, a ninth capacitor, a tenth capacitor, a first resistor, a second resistor, a third resistor, a fifth resistor, a sixth resistor, an eighth resistor and an operational amplifier; the control circuit also includes a fifth capacitor, an eleventh capacitor, a twelfth capacitor, a fourth resistor, a seventh resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a second diode; the output circuit includes a first diode, an eighth capacitor and an output pin.
[0011] In the above technical solution, the circuit configuration is simple, unnecessary complex design is avoided, and the overall performance and indirectness of the mute circuit are improved.
[0012] Furthermore, the two ends of the fourth capacitor are respectively connected to the third capacitor and the sixth capacitor; the third capacitor is connected to the non-inverting input terminal of the operational amplifier through the second resistor and the third resistor in sequence; the sixth capacitor is connected to the inverting input terminal of the operational amplifier through the fifth resistor and the sixth resistor in sequence.
[0013] In the above technical solution, both ends of the fourth capacitor can be configured to collect analog signals; the connection configuration of the fourth capacitor with the third capacitor and the sixth capacitor can provide a filtering function to remove high-frequency noise or unnecessary interference in the signal, ensuring that the collected signal is purer; the third capacitor is connected to the non-inverting input terminal of the operational amplifier through the second resistor and the third resistor, and the sixth capacitor is connected to the inverting input terminal through the fifth resistor and the sixth resistor. This configuration helps to accurately adjust the gain of the operational amplifier.
[0014] In addition, the cooperation between the resistors (such as the second resistor, the third resistor, the fifth resistor, and the sixth resistor) and the capacitors ensures the stability of the circuit during signal processing and reduces unnecessary signal fluctuations.
[0015] Furthermore, one end of the seventh capacitor is respectively connected to the second resistor, the second capacitor, the third resistor and the first resistor, and the other end is respectively connected to the fifth resistor, the tenth capacitor, the sixth resistor and the eighth resistor; the two ends of the third resistor are also respectively connected to the first resistor and the first capacitor; the two ends of the sixth resistor are also respectively connected to the eighth resistor and the ninth capacitor; the other end of the eighth resistor is marked with a reference point.
[0016] In the above technical solution, the connection of the seventh capacitor between multiple resistors and capacitors realizes signal coupling and filtering, so that the signal can be transmitted smoothly between different circuit parts. This configuration helps to filter out high-frequency noise and ensure that the signal processing at different stages is more stable and clear; the third resistor helps to set the gain of the operational amplifier by connecting with the first resistor and the first capacitor. This configuration can accurately adjust the gain of the signal, so that the circuit performs well in various applications; the connection of the sixth resistor with the eighth resistor and the ninth capacitor provides additional stability, helps maintain the working state of the circuit, and avoids the influence of signal fluctuations.
[0017] In addition, one end of the eighth resistor is marked with a reference point OP_Vref, providing a stable reference voltage; the setting of the reference voltage helps to maintain the stability of the circuit, making signal processing more reliable, and at the same time provides a consistent reference voltage for the circuit, which helps to reduce errors caused by voltage fluctuations and ensure the accuracy of the circuit.
[0018] Furthermore, the mute circuit also includes a power supply; the operational amplifier also includes a power pin and a ground pin; the power pin is connected to the power supply, and the ground pin is connected to an analog ground.
[0019] In the above technical solution, the power pin of the operational amplifier is directly connected to the power supply to provide the required voltage for the operational amplifier. The stable power supply ensures that the operational amplifier can maintain consistent performance during operation and avoids signal distortion caused by power supply fluctuations. The ground pin of the operational amplifier is connected to the analog ground to provide a stable reference potential, which can reduce ground loop interference and improve the circuit's anti-interference ability.
[0020] Furthermore, one end of the tenth resistor is connected to the base of the first transistor, and the other end is respectively connected to the collector of the third transistor and the ninth resistor; one end of the ninth resistor is connected to the collector of the third transistor at the junction of the tenth resistor, and the other end is connected to the base of the second transistor.
[0021] In the above technical solution, resistors are set between the first transistor and the third transistor, and between the second transistor and the third transistor, in order to control the distribution ratio of the signal among the multiple transistors through appropriate resistance values, so as to effectively control the conduction of the first transistor and the second transistor; at the same time, the resistors can also prevent excessive current from flowing through the transistors, thereby protecting the transistors from damage and improving the stability of the circuit.
[0022] Furthermore, one end of the fifth capacitor is respectively connected to the first resistor, the first capacitor and the output end of the operational amplifier, and the other end is respectively connected to the emitter of the first transistor and the seventh resistor; one end of the fourth resistor is respectively connected to the fifth capacitor, the emitter of the first transistor and the seventh resistor, and the other end is connected to the emitter of the second transistor and connected to the negative electrode of the first diode.
[0023] In the above technical solution, the fifth capacitor provides coupling between the output end of the operational amplifier and the emitter of the first transistor, ensuring smooth transmission of the signal from the operational amplifier to the transistor. The capacitor can filter out high-frequency noise and interference, providing cleaner signal transmission, thereby improving the overall performance of the circuit; the configuration of the fourth resistor helps to set and stabilize the operating point of the first transistor, affecting the gain and signal processing, and the cooperation with the fifth capacitor and the seventh resistor can improve the stability of the circuit and reduce signal distortion and noise interference; the fourth resistor is connected to the emitter of the first transistor to help control the current path and ensure that the transistor operates in its optimal working state. The reasonable configuration of resistors and capacitors helps to match the circuit load and optimize signal transmission and power consumption.
[0024] Furthermore, the base of the third transistor is connected to the twelfth capacitor, and is connected to the positive electrode of the second diode by merging with the eleventh capacitor, and the emitter of the third transistor is connected to the power supply; the eleventh capacitor and the twelfth capacitor are connected and are connected to the analog ground; the cathode of the second diode is respectively connected to the MUTE pin and the eleventh resistor.
[0025] In the above technical solution, the twelfth capacitor is connected to the base of the third transistor to ensure that the signal is effectively transmitted from the previous circuit to the third transistor and optimize signal coupling. The eleventh capacitor and the twelfth capacitor are connected to the analog ground together to effectively filter out high-frequency noise and interference in the circuit and improve the quality of the signal. Connecting the emitter of the third transistor to the power supply can provide a stable operating point to ensure that the transistor operates under normal working conditions. The gain of the transistor is controlled by the configuration of the capacitor to optimize the circuit performance. The configuration of the diode protects the circuit from excessive voltage or current to prevent signal distortion or component damage. By controlling the conduction and shutdown of the diode through the MUTE pin, mute control of the signal path can be achieved. The eleventh resistor helps match the circuit load to ensure effective transmission and processing of the signal in the circuit. It can also limit the current passing through the diode and other circuit components to protect the circuit from damage due to excessive current.
[0026] Furthermore, the seventh resistor, the eleventh resistor, the collector of the first transistor and the collector of the second transistor are all connected to the analog ground.
[0027] Furthermore, the cathode of the first diode is also connected to one end of the eighth capacitor and connected to the output pin, and a test point is marked at the junction; the anode of the first diode is connected to the other end of the eighth capacitor and connected to the analog ground.
[0028] In the above technical scheme, the eighth capacitor is connected to the cathode of the first diode, which can effectively filter out the spikes and noise of the signal and make the signal smoother. By selecting a suitable capacitance value, the attenuation of the signal can be controlled to ensure the quality of the output signal. The positive electrode of the first diode is connected to the analog ground, which helps to protect the circuit components and prevent excessive voltage or current from damaging the circuit. The test point set at the junction before the output pin is convenient for analysis using an oscilloscope or other test equipment, which facilitates circuit debugging and performance verification. When a circuit fails, the marked test point helps to quickly locate the fault point and improve the efficiency of troubleshooting. The unidirectional conductive characteristics of the first diode and its cooperation with the eighth capacitor further improve the performance of the circuit. The cooperation between the first diode and the eighth capacitor helps to buffer transient overvoltages in the circuit and improve the stability of the circuit.
[0029] Furthermore, by properly configuring the capacitors and resistors, the stability and reliability of the circuit can be ensured; and the relevant parameters of each resistor and capacitor can be configured by those skilled in the art according to actual application requirements.
[0030] Compared with the prior art, the beneficial effects of this application are:
[0031] The mute circuit described in the present application includes an operational amplifier circuit, a control circuit and an output circuit; the control circuit at least includes a MUTE pin, a first transistor, a second transistor and a third transistor; the base of the third transistor is connected to the MUTE pin, the collector of the third transistor is respectively connected to the base of the first transistor and the base of the second transistor, and the emitter of the first transistor and the emitter of the second transistor are connected to the output circuit; wherein the MUTE pin outputs a low level to the third transistor, driving the first transistor and the second transistor to be turned on, so as to pull the analog signal received by the operational amplifier circuit down to the ground potential, block the output circuit from outputting the analog signal, and thereby achieve a mute effect.
[0032] The circuit design of the present application has a simple structure and is easy to integrate with other circuit modules; since the connection method between the control signal (MUTE pin) and the transistor is direct and effective, the mute function can be easily implemented in various devices without complex external control logic. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a schematic diagram of the mute circuit described in this application.
[0034] Figure 2 Schematic diagram of the operational amplifier circuit described in this application.
[0035] Figure 3 This is a schematic diagram of the control circuit described in this application.
[0036] Figure 4 This is a schematic diagram of the output circuit described in this application. DETAILED DESCRIPTION
[0037] A mute circuit of the present application is further described in detail below in conjunction with specific embodiments and drawings.
[0038] See also Figure 1 The present application provides a mute circuit, including an operational amplifier circuit (such as Figure 2 As shown), control circuit (such as Figure 3 as shown) and output circuit (as Figure 4 as shown).
[0039] The control circuit at least includes a MUTE pin, a first transistor Q1, a second transistor Q2 and a third transistor Q3.
[0040] The MUTE pin is a pin used to control an audio device or an audio chip. When the MUTE pin is activated, that is, a corresponding logic level is applied to the pin, corresponding signal control can be achieved.
[0041] The base of the third transistor Q3 is connected to the MUTE pin, the collector of the third transistor Q3 is respectively connected to the base of the first transistor Q1 and the base of the second transistor Q2, and the emitter of the first transistor Q1 and the emitter of the second transistor Q2 are connected to the output circuit.
[0042] Among them, the MUTE pin outputs a low level to the third transistor Q3, driving the first transistor Q1 and the second transistor Q2 to be turned on, so as to pull the analog signal received by the operational amplifier circuit down to the ground potential, block the output circuit from outputting the analog signal, and thus achieve a mute effect.
[0043] In the above technical solution, the control circuit uses a MUTE pin and a transistor, which has a simple and intuitive structure. The three transistors are controlled by a low-level signal of a MUTE pin, which can effectively realize mute control. This structure avoids complex control logic, making circuit design and debugging relatively simple; by turning on the first transistor Q1 and the second transistor Q2, the signal is pulled down to the ground potential, which can achieve fast and effective mute, ensuring that the signal will not leak to the output circuit in the mute state, thereby ensuring an efficient mute effect; the switching speed of the transistor is fast, and it can quickly respond to the control signal of the MUTE pin to provide a real-time mute function, and the power consumption of the transistor is low when working in the switching state, which will not have a significant impact on the overall power consumption of the system.
[0044] In addition, the circuit design has a simple structure and is easy to integrate with other circuit modules; since the connection method between the control signal (MUTE pin) and the transistor is direct and effective, the mute function can be easily implemented in various devices without complex external control logic.
[0045] Further, the operational amplifier circuit includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a sixth capacitor C6, a seventh capacitor C7, a ninth capacitor C9, a tenth capacitor C10, a first resistor R1, a second resistor R2, a third resistor R3, a fifth resistor R5, a sixth resistor R6, an eighth resistor R8 and an operational amplifier U1; the control circuit also includes a fifth capacitor C5, an eleventh capacitor C11, a twelfth capacitor C12, a fourth resistor R4, a seventh resistor R7, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11 and a second diode D2; the output circuit includes a first diode D1, an eighth capacitor C8 and an output pin (see Figure 1 (see Analog_OUT in the figure).
[0046] In the above technical solution, the circuit configuration is simple, which avoids unnecessary complex design and improves the overall performance and indirectness of the mute circuit.
[0047] Furthermore, the two ends of the fourth capacitor C4 are respectively connected to the third capacitor C3 and the sixth capacitor C6; the third capacitor C3 is connected to the non-inverting input terminal of the operational amplifier U1 through the second resistor R2 and the third resistor R3 in sequence; the sixth capacitor C6 is connected to the inverting input terminal of the operational amplifier U1 through the fifth resistor R5 and the sixth resistor R6 in sequence.
[0048] In the above technical solution, both ends of the fourth capacitor C4 can be configured to collect analog signals; the connection configuration of the fourth capacitor C4, the third capacitor C3 and the sixth capacitor C6 can provide a filtering function to remove high-frequency noise or unnecessary interference in the signal, ensuring that the collected signal is purer; the third capacitor C3 is connected to the non-inverting input terminal of the operational amplifier U1 through the second resistor R2 and the third resistor R3, and the sixth capacitor C6 is connected to the inverting input terminal through the fifth resistor R5 and the sixth resistor R6. This configuration helps to accurately adjust the gain of the operational amplifier U1.
[0049] In addition, the cooperation between the resistors (such as the second resistor R2, the third resistor R3, the fifth resistor R5, and the sixth resistor R6) and the capacitors ensures the stability of the circuit during the signal processing and reduces unnecessary signal fluctuations.
[0050] Furthermore, one end of the seventh capacitor C7 is respectively connected to the second resistor R2, the second capacitor C2, the third resistor R3 and the first resistor R1, and the other end is respectively connected to the fifth resistor R5, the tenth capacitor C10, the sixth resistor R6 and the eighth resistor R8; the two ends of the third resistor R3 are also respectively connected to the first resistor R1 and the first capacitor C1; the two ends of the sixth resistor R6 are also respectively connected to the eighth resistor R8 and the ninth capacitor C9; the other end of the eighth resistor R8 is marked with a reference point.
[0051] In the above technical solution, the connection of the seventh capacitor C7 between multiple resistors and capacitors realizes signal coupling and filtering, so that the signal can be smoothly transmitted between different circuit parts. This configuration helps to filter out high-frequency noise and ensure that the signal processing at different stages is more stable and clear; the third resistor R3 helps to set the gain of the operational amplifier U1 by connecting with the first resistor R1 and the first capacitor C1. This configuration can accurately adjust the gain of the signal, so that the circuit performs well in various applications; the connection of the sixth resistor R6 with the eighth resistor R8 and the ninth capacitor C9 provides additional stability, helps maintain the working state of the circuit, and avoids the influence of signal fluctuations.
[0052] In addition, one end of the eighth resistor R8 is marked with a reference point OP_Vref, providing a stable reference voltage; the setting of the reference voltage helps to maintain the stability of the circuit, making signal processing more reliable, and at the same time provides a consistent reference voltage for the circuit, which helps to reduce errors caused by voltage fluctuations and ensure the accuracy of the circuit.
[0053] Furthermore, the mute circuit also includes a power supply; the operational amplifier U1 also includes a power pin and a ground pin; the power pin is connected to the power supply, and the ground pin is connected to an analog ground.
[0054] In the above technical solution, the power pin of the operational amplifier U1 is directly connected to the power supply to provide the required voltage for the operational amplifier U1. The stable power supply ensures that the operational amplifier U1 can maintain consistent performance during operation and avoids signal distortion caused by power supply fluctuations. The ground pin of the operational amplifier U1 is connected to the analog ground to provide a stable reference potential, which can reduce ground loop interference and improve the anti-interference ability of the circuit.
[0055] Furthermore, one end of the tenth resistor R10 is connected to the base of the first transistor Q1, and the other end is respectively connected to the collector of the third transistor Q3 and the ninth resistor R9; one end of the ninth resistor R9 is connected to the collector of the third transistor Q3 at the junction of the tenth resistor R10, and the other end is connected to the base of the second transistor Q2.
[0056] In the above technical solution, resistors are arranged between the first transistor Q1 and the third transistor Q3, and between the second transistor Q2 and the third transistor Q3, in order to control the distribution ratio of the signal among the multiple transistors through appropriate resistance values, so as to effectively control the conduction of the first transistor Q1 and the second transistor Q2; at the same time, the resistors can also prevent excessive current from flowing through the transistors, thereby protecting the transistors from damage and improving the stability of the circuit.
[0057] Furthermore, one end of the fifth capacitor C5 is respectively connected to the first resistor R1, the first capacitor C1 and the output end of the operational amplifier U1, and the other end is respectively connected to the emitter of the first transistor Q1 and the seventh resistor R7; one end of the fourth resistor R4 is respectively connected to the fifth capacitor C5, the emitter of the first transistor Q1 and the seventh resistor R7, and the other end is connected to the emitter of the second transistor Q2 and connected to the cathode of the first diode D1.
[0058] In the above technical solution, the fifth capacitor C5 provides coupling between the output end of the operational amplifier U1 and the emitter of the first transistor Q1, ensuring smooth transmission of the signal from the operational amplifier U1 to the transistor. The capacitor can filter out high-frequency noise and interference, provide cleaner signal transmission, and thus improve the overall performance of the circuit; the configuration of the fourth resistor R4 helps to set and stabilize the operating point of the first transistor Q1, affecting the gain and signal processing, and the cooperation with the fifth capacitor C5 and the seventh resistor R7 can improve the stability of the circuit and reduce signal distortion and noise interference; the fourth resistor R4 is connected to the emitter of the first transistor Q1 to help control the current path and ensure that the transistor operates in its optimal working state. The reasonable configuration of resistors and capacitors helps to match the circuit load and optimize signal transmission and power consumption.
[0059] Furthermore, the base of the third transistor Q3 is connected to the twelfth capacitor C12, and is connected to the positive electrode of the second diode D2 by merging with the eleventh capacitor C11, and the emitter of the third transistor Q3 is connected to the power supply; the eleventh capacitor C11 and the twelfth capacitor C12 are connected and are connected to the analog ground; the cathode of the second diode D2 is respectively connected to the MUTE pin and the eleventh resistor R11.
[0060] In the above technical solution, the twelfth capacitor C12 is connected to the base of the third transistor Q3 to ensure that the signal is effectively transmitted from the previous circuit to the third transistor Q3 and optimize signal coupling. The eleventh capacitor C11 and the twelfth capacitor C12 are connected to the analog ground together to effectively filter out high-frequency noise and interference in the circuit and improve the signal quality. Connecting the emitter of the third transistor Q3 to the power supply can provide a stable operating point to ensure that the transistor operates under normal working conditions. The gain of the transistor is controlled by the configuration of the capacitor to optimize the circuit performance. The configuration of the diode protects the circuit from excessive voltage or current to prevent signal distortion or component damage. By controlling the conduction and shutdown of the diode through the MUTE pin, mute control of the signal path can be achieved. The eleventh resistor R11 helps match the circuit load to ensure effective transmission and processing of the signal in the circuit. It can also limit the current passing through the diode and other circuit components to protect the circuit from damage due to excessive current.
[0061] Furthermore, the seventh resistor R7, the eleventh resistor R11, the collector of the first transistor Q1 and the collector of the second transistor Q2 are all connected to the analog ground.
[0062] Furthermore, the cathode of the first diode D1 is also connected to one end of the eighth capacitor C8 and connected to the output pin (see Figure 1 The anode of the first diode D1 and the other end of the eighth capacitor C8 are connected to the analog ground.
[0063] In the above technical solution, the eighth capacitor C8 is connected to the cathode of the first diode D1, which can effectively filter out the peaks and noise of the signal, making the signal smoother. By selecting a suitable capacitance value, the attenuation of the signal can be controlled to ensure the quality of the output signal; the anode of the first diode D1 is connected to the analog ground to help protect the circuit components and prevent excessive voltage or current from damaging the circuit; at the output pin (see Figure 1The test point set at the junction before the Analog_OUT in the figure is convenient for analysis using an oscilloscope or other test equipment, which is convenient for circuit debugging and performance verification. In addition, when a circuit fails, the marked test point helps to quickly locate the fault point and improve the efficiency of troubleshooting. The unidirectional conductive characteristic of the first diode D1 and its cooperation with the eighth capacitor C8 further improve the performance of the circuit. The cooperation between the first diode D1 and the eighth capacitor C8 helps to buffer transient overvoltages in the circuit and improve the stability of the circuit.
[0064] Furthermore, by properly configuring the capacitors and resistors, the stability and reliability of the circuit can be ensured; and the relevant parameters of each resistor and capacitor can be configured by those skilled in the art according to actual application requirements.
[0065] When this application is working, specifically:
[0066] The analog signal is collected at both ends of the fourth capacitor C4 (see Figure 1 The analog signal is transmitted to the operational amplifier U1 through the link where the third capacitor C3 and the sixth capacitor C6 are located; when the mute effect is not required, the analog signal is amplified by the operational amplifier U1 and then directly transmitted to the output pin through the fifth capacitor C5 and the fourth resistor R4 (see Figure 1 Analog_OUT in the figure) for output.
[0067] The MUTE pin is externally connected to the main control. When a mute effect is required, the main control sets the MUTE pin to a low level. At this time, the third transistor Q3 is turned on, and the 3.3V voltage connected to the third transistor Q3 is directly added to the base of the first transistor Q1 and the base of the second transistor Q2. At this time, a low-impedance path is formed between the collector and the emitter of the first transistor Q1 and the second transistor Q2, thereby turning on the first transistor Q1 and the second transistor Q2.
[0068] After the first transistor Q1 and the second transistor Q2 are turned on, a current path is formed, causing the analog signal to be pulled low. Specifically:
[0069] When the first transistor Q1 and the second transistor Q2 are turned on, the low impedance path between their collectors and emitters connects the analog signal to the ground or close to the ground potential, resulting in a decrease in the signal level.
[0070] Among them, the current of the analog signal flows to the ground (analog ground) through the path from the collector to the emitter of the first transistor Q1 and the second transistor Q2, so that the analog signal level is reduced, thereby achieving the effect of "pulling down" the signal; in this way, in the path of the analog signal, the analog signal level is reduced or muted, thereby realizing the mute function.
[0071] In summary, the present application provides a mute circuit, which includes an operational amplifier circuit, a control circuit and an output circuit; the control circuit includes at least a MUTE pin, a first transistor Q1, a second transistor Q2 and a third transistor Q3; the base of the third transistor Q3 is connected to the MUTE pin, the collector of the third transistor Q3 is connected to the base of the first transistor Q1 and the base of the second transistor Q2 respectively, and the emitter of the first transistor Q1 and the emitter of the second transistor Q2 are connected to the output circuit; wherein the MUTE pin outputs a low level to the third transistor Q3, driving the first transistor Q1 and the second transistor Q2 to conduct, so as to pull the analog signal received by the operational amplifier circuit down to the ground potential, block the output circuit from outputting the analog signal, and thus achieve a mute effect. The circuit design of the present application has a simple structure and is easy to integrate with other circuit modules; since the connection method between the control signal (MUTE pin) and the transistor is direct and effective, the mute function can be easily implemented in various devices without complex external control logic.
[0072] Although example embodiments have been described herein with reference to the accompanying drawings, it should be understood that the above example embodiments are merely exemplary and are not intended to limit the scope of the present application to this. Those of ordinary skill in the art may make various changes and modifications therein without departing from the scope and spirit of the present application. All these changes and modifications are intended to be included within the scope of the present application as required by the appended claims.
[0073] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.
[0074] Although the description of the present application is carried out in conjunction with the above specific embodiments, it is obvious that those skilled in the art can make many substitutions, modifications and changes based on the above content. Therefore, all such substitutions, improvements and changes are included in the spirit and scope of the appended claims.
Claims
1. A mute circuit, characterized in that: Including operational amplifier circuit, control circuit and output circuit; The control circuit at least includes a MUTE pin, a first transistor, a second transistor and a third transistor; The base of the third transistor is connected to the MUTE pin, the collector of the third transistor is respectively connected to the base of the first transistor and the base of the second transistor, and the emitter of the first transistor and the emitter of the second transistor are connected to the output circuit; Among them, the MUTE pin outputs a low level to the third transistor, driving the first transistor and the second transistor to be turned on, so as to pull the analog signal received by the operational amplifier circuit down to the ground potential, block the output circuit from outputting the analog signal, and thus achieve a mute effect.
2. The mute circuit according to claim 1, characterized in that: The operational amplifier circuit includes a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a sixth capacitor, a seventh capacitor, a ninth capacitor, a tenth capacitor, a first resistor, a second resistor, a third resistor, a fifth resistor, a sixth resistor, an eighth resistor and an operational amplifier; The control circuit further includes a fifth capacitor, an eleventh capacitor, a twelfth capacitor, a fourth resistor, a seventh resistor, a ninth resistor, a tenth resistor, an eleventh resistor and a second diode; The output circuit includes a first diode, an eighth capacitor and an output pin.
3. The mute circuit according to claim 2, characterized in that: Two ends of the fourth capacitor are connected to the third capacitor and the sixth capacitor respectively; The third capacitor is connected to the non-inverting input terminal of the operational amplifier through the second resistor and the third resistor in sequence; The sixth capacitor is connected to the inverting input terminal of the operational amplifier through the fifth resistor and the sixth resistor in sequence.
4. The mute circuit according to claim 2, characterized in that: One end of the seventh capacitor is connected to the second resistor, the second capacitor, the third resistor and the first resistor respectively, and the other end is connected to the fifth resistor, the tenth capacitor, the sixth resistor and the eighth resistor respectively; The two ends of the third resistor are also connected to the first resistor and the first capacitor respectively; The two ends of the sixth resistor are also connected to the eighth resistor and the ninth capacitor respectively; The other end of the eighth resistor is marked with a reference point.
5. The mute circuit according to claim 2, characterized in that: The mute circuit also includes a power supply; The operational amplifier also includes a power pin and a ground pin; The power pin is connected to the power supply, and the ground pin is connected to the analog ground.
6. The mute circuit according to claim 2, characterized in that: One end of the tenth resistor is connected to the base of the first transistor, and the other end is connected to the collector of the third transistor and the ninth resistor respectively; One end of the ninth resistor is connected to the collector of the third transistor by merging with the tenth resistor, and the other end is connected to the base of the second transistor.
7. The mute circuit according to claim 2, characterized in that: One end of the fifth capacitor is respectively connected to the first resistor, the first capacitor and the output end of the operational amplifier, and the other end is respectively connected to the emitter of the first transistor and the seventh resistor; One end of the fourth resistor is respectively connected to the fifth capacitor, the emitter of the first transistor and the seventh resistor, and the other end is joined to the emitter of the second transistor and connected to the cathode of the first diode.
8. The mute circuit according to claim 5, characterized in that: The base of the third transistor is connected to the twelfth capacitor and is connected to the positive electrode of the second diode by merging with the eleventh capacitor, and the emitter of the third transistor is connected to the power supply; The eleventh capacitor and the twelfth capacitor are connected and merged to access the analog ground; The cathode of the second diode is connected to the MUTE pin and the eleventh resistor respectively.
9. The mute circuit according to claim 2, characterized in that: The seventh resistor, the eleventh resistor, the collector of the first transistor and the collector of the second transistor are all connected to the analog ground.
10. The mute circuit according to claim 2, characterized in that: The cathode of the first diode is also connected to one end of the eighth capacitor and connected to the output pin, and a test point is marked at the junction; The anode of the first diode and the other end of the eighth capacitor are connected to the analog ground.