Audio analog switch circuit and audio device

Abstract

The application provides an audio analog switch circuit and an audio device. The audio analog switch circuit comprises a negative voltage generation module, a level selection module, a first clamping module, a second clamping module, a first control module, a second control module, a first switch module and a second switch module. The negative voltage generation module is electrically connected with the first clamping module and the second clamping module respectively. The level selection module is electrically connected with the first clamping module and the second clamping module respectively. The first control module is electrically connected with the first clamping module and the first switch module respectively. The second control module is electrically connected with the second clamping module and the second switch module respectively. The audio analog switch circuit provided by the application embodiment significantly improves the off-isolation of the switch module, especially in the high-frequency audio signal scene, effectively suppresses the signal leakage between channels, guarantees the purity of audio signal transmission, greatly improves the fidelity of the audio system, and can fully meet the demand of the audio device for high-isolation.

Description

Technical Field

[0001] This application belongs to the field of audio equipment technology, and in particular relates to an audio analog switch circuit and an audio device. Background Technology

[0002] In signal path switching scenarios of portable consumer electronic audio devices, depletion-type MOS analog switches are widely used due to their bypass characteristics of automatic turn-on upon power failure. However, their signal isolation performance in the off state is always limited by the inherent leakage path. In existing technical solutions, the main power transistors corresponding to the first and second ports usually share a set of gate control circuits. The audio signal (especially high-frequency signal) at the first port will be coupled to the common gate line through the gate-drain parasitic capacitance of the main power transistor, and then leak to the second port through the gate-drain parasitic capacitance of the main power transistor corresponding to the second port, forming a leakage path. This leakage path will cause a significant decrease in the switch turn-off isolation. Summary of the Invention

[0003] This application provides an audio analog switch circuit and an audio device, which can solve the problem of low turn-off isolation of depletion-type MOS analog switches in existing audio analog switch circuits.

[0004] In a first aspect, embodiments of this application provide an audio analog switch circuit, including a negative voltage generation module, a level selection module, a first clamping module, a second clamping module, a first control module, a second control module, a first switch module, and a second switch module. The negative voltage generation module is electrically connected to the first clamping module and the second clamping module, the level selection module is electrically connected to the first clamping module and the second clamping module, the first control module is electrically connected to the first clamping module and the first switch module, and the second control module is electrically connected to the second clamping module and the second switch module.

[0005] When powered, the negative voltage generating module outputs a first negative voltage; the level selection module outputs a first comparison voltage to the first clamping module and a second comparison voltage to the second clamping module based on the first port voltage, the second port voltage, and a reference voltage; the first clamping module outputs a first clamping voltage to the first control module based on the first comparison voltage and the first negative voltage, and the first control module controls the first switching module to turn off based on the first clamping voltage; the second clamping module outputs a second clamping voltage to the second control module based on the second comparison voltage and the first negative voltage, and the second control module controls the second switching module to turn off based on the second clamping voltage.

[0006] In one possible implementation of the first aspect, the level selection module includes a first level selection unit and a second level selection unit, wherein the first level selection unit is electrically connected to the first clamping module, and the second level selection unit is electrically connected to the second clamping module;

[0007] The first level selection unit is used to compare the first port voltage and the reference voltage, and output the first comparison voltage to the first clamping module. The first comparison voltage is the minimum voltage between the first port voltage and the reference voltage. The second level selection unit is used to compare the second port voltage and the reference voltage, and output the second comparison voltage to the second clamping module. The second comparison voltage is the minimum voltage between the second port voltage and the reference voltage.

[0008] In one possible implementation of the first aspect, the first clamping voltage includes a first clamping sub-voltage and a second clamping sub-voltage, wherein the first clamping sub-voltage is less than the difference between the second clamping sub-voltage and a first preset voltage, and the second clamping voltage is less than the difference between the first comparison voltage and the second preset voltage.

[0009] The first control module includes a first switching transistor, a second switching transistor, and a first resistor;

[0010] The gate of the first switch is used to receive the first clamping sub-voltage. The source of the first switch is electrically connected to the first switch module. The drain of the first switch and the drain of the second switch are both used to receive the first port voltage. The first end of the first resistor is electrically connected to the gate of the second switch and is used to receive the first clamping sub-voltage. The second end of the first resistor is electrically connected to the source of the second switch and the first switch module respectively and is used to receive the second clamping sub-voltage.

[0011] Alternatively, the gate of the first switch is used to receive the first clamping sub-voltage, the source of the first switch is electrically connected to the first switch module, the drain of the first switch and the drain of the second switch are both electrically connected to the first switch module, the second switch module and the second control module, the first end of the first resistor is electrically connected to the source of the second switch and the first switch module respectively, and is used to receive the second clamping sub-voltage, and the second end of the first resistor is electrically connected to the gate of the second switch and is used to receive the first clamping sub-voltage.

[0012] In one possible implementation of the first aspect, the first control module further includes a third switch and a fourth switch, the gate of the third switch and the gate of the fourth switch are both used to receive the second clamping voltage, the third switch is connected in series with the first switch, and the fourth switch is connected in series with the second switch.

[0013] In one possible implementation of the first aspect, the second clamping voltage includes a third clamping sub-voltage and a fourth clamping sub-voltage, wherein the third clamping sub-voltage is less than the difference between the fourth clamping sub-voltage and a third preset voltage, and the fourth clamping voltage is less than the difference between the second comparison voltage and the fourth preset voltage.

[0014] The second control module includes a fifth switch, a sixth switch, and a second resistor;

[0015] The gate of the fifth switch is used to receive the third clamping sub-voltage. The source of the fifth switch is electrically connected to the second switch module. The drain of the fifth switch and the drain of the sixth switch are both used to receive the second port voltage. The first end of the second resistor is electrically connected to the source of the sixth switch and the second switch module respectively, and is used to receive the fourth clamping sub-voltage. The second end of the second resistor is electrically connected to the gate of the sixth switch and is used to receive the third clamping sub-voltage.

[0016] Alternatively, the gate of the fifth switch is used to receive the third clamping sub-voltage, the source of the fifth switch is electrically connected to the second switch module, the drain of the fifth switch and the drain of the sixth switch are both electrically connected to the first switch module, the second switch module and the first control module, the first end of the second resistor is electrically connected to the gate of the sixth switch to receive the third clamping sub-voltage, and the second end of the second resistor is electrically connected to the source of the sixth switch and the second switch module to receive the fourth clamping sub-voltage.

[0017] In one possible implementation of the first aspect, the second control module further includes a seventh switch and an eighth switch, the gate of the seventh switch and the gate of the eighth switch are both used to receive the fourth clamping voltage, the seventh switch is connected in series with the fifth switch, and the eighth switch is connected in series with the sixth switch.

[0018] In one possible implementation of the first aspect, the first switching module includes a first power transistor, the gate and substrate of the first power transistor are both electrically connected to the first control module, the drain of the first power transistor is used to receive the first port voltage, and the source of the first power transistor is electrically connected to the second switching module.

[0019] The second switching module includes a second power transistor, the gate and substrate of which are electrically connected to the second control module. The drain of the second power transistor is used to receive the second port voltage, and the source of the second power transistor is electrically connected to the first switching module.

[0020] In one possible implementation of the first aspect, the level selection module further includes a third level selection unit, the audio analog switch circuit further includes a switch control module and a discharge module, the third level selection unit is electrically connected to the first switch module, the second switch module and the switch control module respectively, and the discharge module and the switch control module are both electrically connected to the negative voltage generating module;

[0021] The third level selection unit is used to compare the node voltage and the reference voltage, and output a third comparison voltage to the switch control module. The third comparison voltage is the maximum voltage between the node voltage and the reference voltage. The node voltage is the voltage at the common terminal of the first switch module and the second switch module. The switch control module is used to turn on the switch according to the power supply voltage, the third comparison voltage, and the first negative voltage. The discharge module is used to discharge the first negative voltage when the power supply is not in operation.

[0022] In one possible implementation of the first aspect, the switch control module includes a ninth switch and a tenth switch. The gate of the ninth switch is used to receive the first negative voltage. The source of the ninth switch is electrically connected to the first switch module and the second switch module, respectively. The drain of the ninth switch is electrically connected to the drain of the tenth switch. The substrate of the ninth switch is electrically connected to the third level selection unit. The gate of the tenth switch is used to receive the power supply voltage, and the source of the tenth switch is used to receive the reference voltage.

[0023] Secondly, embodiments of this application provide an audio device, including the audio analog switch circuit described in any one of the first aspects.

[0024] The beneficial effects of the embodiments in this application compared with the prior art are:

[0025] The audio analog switch circuit provided in this application includes a negative voltage generation module, a level selection module, a first clamping module, a second clamping module, a first control module, a second control module, a first switch module, and a second switch module. When powered on and the first and second switch modules need to be turned off, an independent control architecture is constructed by innovatively setting two independent clamping modules (first clamping module and second clamping module) and two dedicated control modules (first control module and second control module). The first clamping module generates an appropriate first clamping voltage based on the first comparison voltage and the first negative voltage output by the level selection module, which is then used by the first control module to drive the first switch module to turn off. The second clamping module generates an appropriate second clamping voltage based on the second comparison voltage and the first negative voltage, which is then used by the second control module to drive the second switch module to turn off. This dual-channel independent control design completely breaks away from the traditional signal transmission path of the "common gate line" in terms of physical structure: even if the audio signal at the first port is coupled through the gate-drain parasitic capacitance of the first switching module, it is confined to the first independent control channel and cannot be transmitted to the second channel through the common line; similarly, the signal at the second port is also confined to its own control channel, fundamentally cutting off the leakage path of "first port → parasitic capacitance of the first switching module → common line → parasitic capacitance of the second switching module → second port". This design significantly improves the turn-off isolation of the switching modules, especially in high-frequency audio signal scenarios, effectively suppressing signal leakage between channels, ensuring the purity of audio signal transmission, and greatly improving the fidelity of the audio system, which can fully meet the high isolation requirements of high-end noise-canceling headphones, Bluetooth speakers and other portable audio devices. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a circuit diagram of an existing audio analog switch circuit;

[0028] Figure 2 This is a circuit diagram of an existing improved audio analog switch circuit;

[0029] Figure 3 This is a schematic block diagram of an audio analog switch circuit provided in one embodiment of this application;

[0030] Figure 4 This is a schematic block diagram of an audio analog switch circuit provided in another embodiment of this application;

[0031] Figure 5 This is a schematic block diagram of an audio analog switch circuit provided in another embodiment of this application;

[0032] Figure 6 This is a circuit connection diagram of an audio analog switch circuit provided in an embodiment of this application;

[0033] Figure 7 This is a circuit connection diagram of an audio analog switch circuit provided in another embodiment of this application;

[0034] Figure 8 This is a circuit connection diagram of an audio analog switch circuit provided in another embodiment of this application;

[0035] Figure 9 This is a circuit connection diagram of an audio analog switch circuit provided in another embodiment of this application.

[0036] In the diagram, 101 is the negative pressure generating module; 102 is the level selection module; 1021 is the first level selection unit; 1022 is the second level selection unit; 1023 is the third level selection unit; 103 is the first clamping module; 104 is the second clamping module; 105 is the first control module; 106 is the second control module; 107 is the first switch module; 108 is the second switch module; 109 is the switch control module; and 110 is the discharge module. Detailed Implementation

[0037] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0038] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0039] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0040] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if [the described condition or event] is detected" may be interpreted, depending on the context, as "once determined," "in response to determination," "once [the described condition or event] is detected," or "in response to detection of [the described condition or event]."

[0041] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0042] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0043] like Figure 1 As shown, the traditional approach uses a negative charge pump to generate a fixed negative gate voltage to control the turn-on and turn-off of the depletion-type switch. Its basic working principle is as follows: when the system is powered normally and the switch needs to be turned off for signal isolation, the negative charge pump generates a constant negative voltage based on a fixed reference voltage and applies it to the gate of the switch, causing it to turn off; when the system is powered off, the negative charge pump stops working, the negative voltage disappears, and the switch automatically turns on due to its inherent characteristics, forming a signal bypass.

[0044] The above-mentioned traditional solutions have the following essential technical defects: (1) The gate control voltage is fixed and cannot be adjusted: The negative voltage output by the negative charge pump is preset by the internal reference circuit of the chip and cannot be adjusted once the design is completed. The signal isolation capability of the switch depends entirely on the static matching degree between the fixed gate voltage and the threshold voltage of the switching transistor, and cannot adapt to dynamic conditions such as process fluctuations, voltage changes and temperature drift. (2) The contradiction between withstand voltage requirements and turn-off isolation: In order to ensure that audio signals containing negative level components can be turned off, the negative charge pump needs to output a negative voltage with a sufficiently large amplitude. This requires the switching transistor to have a high withstand voltage capability. If high voltage devices are used, it will directly lead to an increase in chip area and cost. More importantly, high voltage devices usually have larger parasitic capacitance, which will further aggravate the deterioration of turn-off isolation at high frequencies. (3) Multi-path parasitic capacitance coupling: There are complex parasitic capacitance coupling paths between the ports of the analog switch (e.g., attached) Figure 1 The signal at port A can be coupled to port B via parasitic capacitances Cgd_a to Cgd_b and Cdb_a to Cdb_b, etc. These parasitic capacitances create additional channels for signal leakage, severely weakening the switch's turn-off isolation capability.

[0045] To alleviate the pressure resistance of traditional solutions, existing technologies have proposed an improved design, such as... Figure 2 As shown in the diagram, this scheme incorporates a level selection circuit, allowing the gate negative voltage generated by the negative charge pump to be dynamically adjusted based on the minimum value of the voltages at the two input ports of the analog switch, rather than remaining fixed. This method reduces the absolute withstand voltage requirement of the switching transistor to some extent, facilitating the use of smaller devices.

[0046] However, this improvement does not fundamentally solve the core technical defect of low switching isolation inherent in depletion-type MOS analog switch structures. The high-pass filtering effect caused by device parasitic capacitance and load resistance still exists, and the parasitic capacitive coupling problem between ports has not been effectively resolved. Therefore, its performance is still insufficient for applications requiring high-fidelity audio switching.

[0047] In summary, existing depletion-mode MOS analog switching circuits, whether using traditional fixed negative voltage schemes or dynamic negative voltage improvement schemes, are limited by insufficient turn-off isolation due to their inherent structure, especially with significant performance degradation under high-frequency audio signals. This restricts their application in high-end portable audio devices.

[0048] To address the aforementioned issues, the audio analog switch circuit provided in this application includes a negative voltage generation module, a level selection module, a first clamping module, a second clamping module, a first control module, a second control module, a first switch module, and a second switch module. When powered on and the first and second switch modules need to be turned off, an independent control architecture is constructed by innovatively setting two independent clamping modules (first clamping module and second clamping module) and two dedicated control modules (first control module and second control module). The first clamping module generates an appropriate first clamping voltage based on the first comparison voltage and the first negative voltage output by the level selection module, which is then used by the first control module to drive the first switch module to turn off. The second clamping module generates an appropriate second clamping voltage based on the second comparison voltage and the first negative voltage, which is then used by the second control module to drive the second switch module to turn off. This dual-channel independent control design completely breaks away from the traditional signal transmission path of the "common gate line" in terms of physical structure: even if the audio signal at the first port is coupled through the gate-drain parasitic capacitance of the first switching module, it is confined to the first independent control channel and cannot be transmitted to the second channel through the common line; similarly, the signal at the second port is also confined to its own control channel, fundamentally cutting off the leakage path of "first port → parasitic capacitance of the first switching module → common line → parasitic capacitance of the second switching module → second port". This design significantly improves the turn-off isolation of the switching modules, especially in high-frequency audio signal scenarios, effectively suppressing signal leakage between channels, ensuring the purity of audio signal transmission, and greatly improving the fidelity of the audio system, which can fully meet the high isolation requirements of high-end noise-canceling headphones, Bluetooth speakers and other portable audio devices.

[0049] To illustrate the technical solution described in this application, specific embodiments are provided below.

[0050] Figure 3 A schematic block diagram of an audio analog switch circuit according to an embodiment of this application is shown. See also... Figure 3 As shown, the audio analog switch circuit includes a negative voltage generation module 101, a level selection module 102, a first clamping module 103, a second clamping module 104, a first control module 105, a second control module 106, a first switch module 107, and a second switch module 108. The negative voltage generation module 101 is electrically connected to the first clamping module 103 and the second clamping module 104, respectively. The level selection module 102 is electrically connected to the first clamping module 103 and the second clamping module 104, respectively. The first control module 105 is electrically connected to the first clamping module 103 and the first switch module 107, respectively. The second control module 106 is electrically connected to the second clamping module 104 and the second switch module 108, respectively.

[0051] Specifically, when the power supply is normal and the first switch module 107 and the second switch module 108 need to be turned off, the negative pressure generating module 101 outputs the first negative pressure V. cp The level selection module 102 outputs a first comparison voltage V based on the first port voltage VA (voltage of the first port A), the second port voltage VB (voltage of the second port B), and the reference voltage VSS (reference ground). mina Second comparison voltage V minb This application innovatively constructs an independent control architecture by setting up two independent clamping modules (first clamping module 103 and second clamping module 104) and two dedicated control modules (first control module 105 and second control module 106). The first clamping module 103 is based on the first comparison voltage V output by the level selection module 102. mina The first negative pressure V output by the negative pressure generation module 101 cp The first clamping voltage is generated and the first control module 105 drives the first switch module 107 to turn off; the second clamping module 104 is based on the second comparison voltage V output by the level selection module 102. minb The first negative pressure V output by the negative pressure generation module 101 cp A matching second clamping voltage is generated, which is then used by the second control module 106 to drive the second switch module 108 to turn off. This dual-path independent control design completely breaks the signal transmission path of the "common gate line" in the traditional solution from a physical structure perspective: even if the audio signal of the first port is coupled through the gate-drain parasitic capacitance of the first switch module 107, it is limited to the first independent control channel and cannot be transmitted to the second channel through the common line; similarly, the signal of the second port is also restricted to its own control channel, cutting off the leakage path "first port A → parasitic capacitance of first switch module 107 → common line → parasitic capacitance of second switch module 108 → second port B" from the root. This design significantly improves the turn-off isolation of the switch module, especially in high-frequency audio signal scenarios, effectively suppressing signal leakage between channels, ensuring the purity of audio signal transmission, and greatly improving the fidelity of the audio system, which can fully meet the high isolation requirements of high-end noise-canceling headphones, Bluetooth speakers and other portable audio devices.

[0052] It should be noted that the negative voltage generation module 101, the level selection module 102, the first clamping module 103, and the second clamping module 104 can be integrated into a control circuit, and the first control module 105, the second control module 106, the first switch module 107, and the second switch module 108 can be integrated into a power switching circuit. Under normal power supply conditions, the control circuit stops working because there is no loss of power, and the first negative voltage V... cpWhen the voltage is zero, the first clamping module 103 and the second clamping module 104 no longer generate effective clamping voltage. At this time, the first switching module 107 and the second switching module 108 enter the natural conduction state due to the inherent characteristics of the internal depletion-type devices. The circuit automatically forms a low-impedance signal path from the first port A through the power switching circuit to the second port B. The continuous transmission of the basic audio signal can be guaranteed without additional control logic, ensuring that the device can still maintain the core audio function in emergency scenarios such as power failure or battery depletion, and significantly improving the user experience.

[0053] It should be noted that the negative pressure generating module 101 can use a negative pressure charge pump as the core implementation unit. Its core function is to generate a first negative pressure V that meets the switching off requirements based on a stable supply voltage under normal power supply conditions. cp This provides a reliable base negative voltage source for the first clamping module 103 and the second clamping module 104 to accurately generate the corresponding clamping voltage, ensuring that the first switching module 107 and the second switching module 108 can obtain sufficient turn-off drive voltage, thereby achieving reliable turn-off across the entire signal amplitude range.

[0054] In one embodiment of this application, such as Figure 4 As shown, the level selection module 102 includes a first level selection unit 1021 and a second level selection unit 1022. The first level selection unit 1021 is electrically connected to the first clamping module 103, and the second level selection unit 1022 is electrically connected to the second clamping module 104.

[0055] Specifically, the first level selection unit 1021 compares the first port voltage VA with the reference voltage VSS in real time, and selects the minimum voltage between the two as the first comparison voltage V. mina The output is sent to the first clamping module 103. Similarly, the second level selection unit 1022 compares the second port voltage VB with the reference voltage VSS and outputs the minimum voltage between the two as the second comparison voltage V. minbThe output is sent to the second clamping module 104. This design, on the one hand, achieves separate tracking and independent output of the potentials of the two ports through two independent level selection units, without signal cross-interference, providing a foundation for the independent operation of the subsequent first clamping module 103 and second clamping module 104, further strengthening the advantages of the dual-channel independent control architecture. On the other hand, by selecting the minimum value between the port voltage and the reference voltage VSS as the comparison voltage, it can ensure that the clamping voltage generated by the subsequent clamping module can dynamically adapt to the signal levels of the first and second ports, so that the control voltages of the first switching module 107 and the second switching module 108 can dynamically track the lowest potential of the input signal. This ensures reliable turn-off of the switching modules across the entire signal amplitude range, avoids incomplete turn-off caused by a fixed reference potential, and eliminates the need to apply excessively high negative voltage, alleviating the voltage withstand pressure on the switching modules, thus balancing turn-off reliability and device selection flexibility.

[0056] against Figure 1 and Figure 2 The existing circuit shown also has another drawback: due to the unavoidable parasitic capacitance (Cdb) between the source / drain of the main power transistor and the device substrate, these inherent parasitic capacitances create an additional signal coupling path between the first port and the second port. Specifically, the audio signal (especially high-frequency signals) at the first port can be conducted to the common intermediate node through the parasitic capacitance between the source / drain of the main power transistor and the substrate, and then further leak to the second port through the parasitic capacitance between the substrate and the source / drain of the main power transistor corresponding to the second port, forming an additional leakage path of "first port A → source / drain - substrate parasitic capacitance → intermediate node → substrate - source / drain parasitic capacitance → second port B", which further deteriorates the switching isolation and exacerbates the channel crosstalk problem.

[0057] Based on the above issues, such as Figure 5 As shown, the level selection module 102 also includes a third level selection unit 1023, and the audio analog switch circuit also includes a switch control module 109 and a discharge module 110. The third level selection unit 1023 is electrically connected to the first switch module 107, the second switch module 108 and the switch control module 109 respectively. The discharge module 110 and the switch control module 109 are both electrically connected to the negative voltage generation module 101.

[0058] Specifically, the third level selection unit 1023 detects the node voltage V at the common terminal of the first switch module 107 and the second switch module 108 in real time. mid The voltage V is selected as the third comparison voltage by comparing it with the reference voltage VSS. body The output is sent to the switch control module 109, enabling it to combine the power supply voltage VDD and the first negative voltage V. cp Compare with the third voltage V bodyTo achieve adaptive conduction control, the node voltage V mid Effective clamping to the reference voltage VSS cuts off additional leakage paths through source / drain-substrate parasitic capacitance, enhancing isolation during shutdown. The discharge module 110 is specifically responsible for rapidly discharging the residual first negative voltage V from the negative voltage generation module 101 when power is off. cp This ensures that the control circuit quickly exits the shutdown control state. The discharge module 110 accelerates the discharge process of negative voltage during power failure, prompting the clamping voltage output by the clamping module to quickly return to a safe level. This ensures that the power switch section can quickly and reliably enter the automatic conduction state, and ensures that the low-impedance emergency signal path is quickly established. This not only guarantees the continuity of basic audio functions, but also improves the flexibility and reliability of the circuit switching between power supply and power failure conditions.

[0059] It should be noted that the first level selection unit 1021, the second level selection unit 1022, and the third level selection unit 1023 mentioned above can all be composed of a voltage comparator as the core, combined with a clamping or gating circuit consisting of diodes and resistors (or can be implemented using an integrated analog multiplexer in conjunction with a comparator). The voltage comparator serves as the core judgment device, used to compare two input voltages (such as the first port voltage VA in the first level selection unit 1021 with the reference voltage VSS, the second port voltage VB in the second level selection unit 1022 with the reference voltage VSS, and the node voltage V in the third level selection unit 1023). mid The comparator and diodes determine the relationship between the voltage and the reference voltage (VSS) and output corresponding logic signals. Diodes enable unidirectional voltage conduction and natural filtering, ensuring only the target extreme voltage (minimum or maximum value) is output, avoiding reverse voltage interference. Resistors limit current and divide voltage, ensuring the comparator and diodes operate within a safe voltage range while stabilizing the circuit's static operating point. The core function of this circuit / device combination is to rapidly respond to dynamic changes in the input voltage, accurately selecting the extreme voltage that meets the requirements of subsequent modules (both the first level selection unit 1021 and the second level selection unit 1022 output the minimum value, and the third level selection unit 1023 outputs the maximum value). This provides a stable and accurate reference signal for the clamping module and the switch control module 109, ensuring the reliable implementation of the control circuit's adaptive adjustment logic, thereby guaranteeing the switch module's turn-off isolation and operating condition switching performance.

[0060] It should be noted that the discharge module 110 can be mainly composed of a switching transistor (such as an enhancement-mode NMOS transistor or a PMOS transistor), a bleeder resistor, and trigger control elements (such as a voltage divider resistor and a Zener diode). Among them, the enhancement-mode NMOS transistor (or PMOS transistor) serves as the core bleeder switch, used to quickly turn on when the power supply is not in operation, establishing the first negative voltage V. cp The discharge path is established. The discharge resistor provides the first negative voltage V when the switching transistor is turned on.cp A low-impedance discharge path is provided while limiting the discharge current to prevent damage to components due to excessive current. A voltage divider resistor and a Zener diode form a trigger control circuit for accurate detection of normal power supply status. When the power supply voltage VDD drops below a threshold, the switching transistor is triggered to turn on promptly, ensuring that the discharge module 110 only starts under power-off conditions and does not affect the stable operation of the negative voltage generation module 101 under normal power supply. Therefore, after power is cut off, the discharge module 110 can quickly dissipate the residual first negative voltage VDD in the negative voltage generation module 101. cp The circuit is discharged to a safe level, quickly releasing the shutdown control of the first switch module 107 and the second switch module 108. This ensures that the switch modules can be turned on naturally in a timely manner by utilizing the characteristics of their internal depletion-type devices, guaranteeing the rapid establishment of an emergency signal path. At the same time, it avoids operating condition switching delays or abnormal switch conduction caused by residual negative voltage, thereby improving circuit reliability and user experience.

[0061] The following is combined with Figures 6 to 9 The circuit diagram shown provides a detailed description of the working principle of the audio analog switch circuit provided in the embodiments of this application.

[0062] It should be clarified that the first clamping voltage includes the first clamping sub-voltage V. cp1a Second clamping voltage V cp2a First clamp voltage V cp1a Less than the second clamping voltage V cp2a The difference between the first preset voltage and the second clamping voltage V cp2a Less than the first comparison voltage V mina The difference between the first and second preset voltages; where the first and second preset voltages are equal and both match the threshold voltage of the depletion-mode MOSFET, ensuring reliable turn-off of the switching module. That is, the first clamping voltage V. cp1a Second clamping voltage V cp2a Satisfy: V cp2a <V mina -|V th_dep |and V cp1a <V cp2a -|V th_dep |, where V th_dep This is the threshold voltage of a depletion-type NMOS.

[0063] The second clamping voltage includes the third clamping voltage V. cp1b and the fourth clamping voltage V cp2b The third clamping voltage V cp1b Less than the fourth clamping voltage V cp2b The difference between the third preset voltage and the fourth clamping voltage V cp2b Less than the second comparison voltage V minbThe difference between the third and fourth preset voltages; where the third and fourth preset voltages are equal and both match the threshold voltage of the depletion-mode MOSFET, ensuring reliable turn-off of the switching module. That is, the third clamping voltage V. cp1b Fourth clamp voltage V cp2b Satisfy: V cp2b <V minb -|V th_dep |and V cp1b <V cp2b -|V th_dep |, where V th_dep This is the threshold voltage of a depletion-type NMOS.

[0064] In one embodiment of this application, such as Figure 6 As shown, the first control module 105 includes a first switch M1, a second switch M2, and a first resistor R1; the gate of the first switch M1 is used to receive the first clamping voltage V. cp1a The source of the first switching transistor M1 is electrically connected to the first switching module 107. The drains of both the first switching transistor M1 and the second switching transistor M2 are used to receive the first port voltage VA. The first terminal of the first resistor R1 is electrically connected to the gate of the second switching transistor M2 and is used to receive the first clamping voltage V. cp1a The second terminal of the first resistor R1 is electrically connected to the source of the second switching transistor M2 and the first switching module 107, respectively, to receive the second clamping voltage V. cp2a .

[0065] Specifically, the first switching transistor M1 serves as the core gate driver, and its gate receives the first clamping voltage V. cp1a By controlling its own reliable shutdown through this voltage, the body diode of the depletion-type MOSFET in the first switching module 107 is prevented from conducting; the gate of the second switching transistor M2 also receives the first clamping voltage V. cp1a The source of the second switch M2 receives the second clamping voltage V. cp2a Due to the first clamping voltage V cp1a Below the second clamping voltage V cp2a The turn-on threshold of a MOSFET, i.e., the gate voltage of the second switch M2 is lower than the source voltage by a threshold voltage, ensures that the second switch M2 can be reliably turned off. The first resistor R1 is to prevent the generation of V0. cp1a The negative pressure charge pump is pulled down. Due to the presence of the first resistor R1, the charge pump will not be pulled down, the second switch M2 can be turned off, and finally the first switch module 107 can be turned off.

[0066] For example, designers can select the types of the first switch M1 and the second switch M2 according to the actual situation. For instance, both the first switch M1 and the second switch M2 can be selected as depletion-type NMOS transistors.

[0067] In one embodiment of this application, such as Figure 6 As shown, the second control module 106 includes a fifth switch M5, a sixth switch M6, and a second resistor R2; the gate of the fifth switch M5 is used to receive the third clamping voltage V. cp1b The source of the fifth switch M5 is electrically connected to the second switch module 108. The drains of both the fifth switch M5 and the sixth switch M6 are used to receive the second port voltage VB. The first terminal of the second resistor R2 is electrically connected to the source of the sixth switch M6 and the second switch module 108, respectively, to receive the fourth clamping voltage V. cp2b The second terminal of the second resistor R2 is electrically connected to the gate of the sixth switch M6 to receive the third clamping voltage V. cp1b .

[0068] Specifically, the fifth switch M5 serves as the core gate driver, and its gate receives the third clamping voltage V. cp1b This voltage control ensures reliable shutdown, preventing the body diode of the depletion-type MOSFET in the second switching module 108 from conducting; the gate of the sixth switching transistor M6 also receives the third clamping voltage V. cp1b The source of the sixth switch M6 receives the fourth clamping voltage V. cp2b Due to the third clamp voltage V cp1b Below the fourth clamping voltage V cp2b The turn-on threshold of a MOSFET, i.e., the gate voltage of the sixth switch M6 is lower than the source voltage by one threshold voltage, allows the sixth switch M6 to be reliably turned off. The second resistor R2 acts as a current limiter, restricting the current between the gate and source of the sixth switch M6, protecting the device from damage by excessive current, and enhancing the turn-off isolation effect while achieving reliable turn-off.

[0069] For example, designers can select the types of the fifth switch M5 and the sixth switch M6 according to the actual situation. For instance, both the fifth switch M5 and the sixth switch M6 can be selected as depletion-type NMOS transistors.

[0070] It should be noted that the connection relationship between the first switch M1, the second switch M2, and the first resistor R1 can be changed and optimized, such as... Figure 7 As shown, the gate of the first switching transistor M1 is used to receive the first clamping voltage V. cp1aThe source of the first switching transistor M1 is electrically connected to the first switching module 107. The drains of both the first switching transistor M1 and the second switching transistor M2 are electrically connected to the first switching module 107, the second switching module 108, and the second control module 106. The first terminal of the first resistor R1 is electrically connected to the source of the second switching transistor M2 and the first switching module 107, respectively, for receiving the second clamping voltage V. cp2a The second terminal of the first resistor R1 is electrically connected to the gate of the second switch M2 to receive the first clamping voltage V. cp1a Because the first switch M1, the second switch M2, and the first resistor R1 are in Figure 7 The role of in and in the above Figure 6 The function is the same as that in the previous section, so I won't go into too much detail here.

[0071] It should be noted that the connection relationship between the fifth switch M5, the sixth switch M6, and the second resistor R2 can be changed and optimized, such as... Figure 7 As shown, the gate of the fifth switch M5 is used to receive the third clamping voltage V. cp1b The source of the fifth switch M5 is electrically connected to the second switch module 108. The drains of both the fifth switch M5 and the sixth switch M6 are electrically connected to the first switch module 107, the second switch module 108, and the first control module 105. The first terminal of the second resistor R2 is electrically connected to the gate of the sixth switch M6 to receive the third clamping voltage V. cp1b The second terminal of the second resistor R2 is electrically connected to the source of the sixth switch transistor M6 and the second switch module 108, respectively, to receive the fourth clamping voltage V. cp2b Because the fifth switch M5, the sixth switch M6, and the second resistor R2 are in Figure 7 The role of in and in the above Figure 6 The function is the same as that in the previous section, so I won't go into too much detail here.

[0072] In one embodiment of this application, such as Figure 6 and Figure 7 As shown, the first switching module 107 includes a first power transistor M. power1 The first power transistor M power1 Both the gate and substrate ends are electrically connected to the first control module 105, and the first power transistor M power1 The drain of the first power transistor M is used to receive the first port voltage VA. power1 The source is electrically connected to the second switch module 108.

[0073] The second switching module 108 includes a second power transistor M. power2 Second power transistor M power2 Both the gate and substrate ends are electrically connected to the second control module 106, and the second power transistor M power2The drain of the second power transistor M is used to receive the second port voltage VB. power2 The source is electrically connected to the first switch module 107.

[0074] Specifically, the first power transistor M power1 Second power transistor M power2 Connected in series between the first port A and the second port B, when the power supply is normal, the first power transistor M... power1 By precisely controlling the negative voltage at the gate to enter a high-impedance turn-off state, the signal transmission from the first port A to the common node is blocked. Simultaneously, isolation control at the substrate prevents the body diode from conducting or substrate parasitic capacitance coupling from forming a leakage path. Similarly, the second power transistor M... power2 When the power supply is normal, it is reliably shut off, blocking the leakage of the common node signal to the second port B. The two are connected in series to form "first port A → first power transistor M". power1 →Common Node→Second Power Transistor M power2 →The complete signal path of the second port B” enhances the isolation effect through dual high-impedance states when it is off, and forms a low-impedance path by virtue of the depletion-mode device characteristics when it is on, ensuring low-distortion transmission of audio signals. This satisfies the high isolation requirement and ensures the reliable implementation of the emergency bypass function when power is off.

[0075] For example, designers can modify the first power transistor M according to the actual situation. power1 Second power transistor M power2 The type can be selected, for example, the first power transistor M can be selected. power1 Second power transistor M power2 All are depletion-type NMOS transistors.

[0076] In one embodiment of this application, such as Figure 6 and Figure 7 As shown, the switch control module 109 includes a ninth switch M9 and a tenth switch M10. The gate of the ninth switch M9 is used to receive the first negative voltage V. cp The source of the ninth switch M9 is electrically connected to the first switch module 107 and the second switch module 108, respectively. The drain of the ninth switch M9 is electrically connected to the drain of the tenth switch M10. The substrate of the ninth switch M9 is electrically connected to the third level selection unit 1023. The gate of the tenth switch M10 is used to receive the power supply voltage VDD, and the source of the tenth switch M10 is used to receive the reference voltage VSS.

[0077] Specifically, when the power supply is normal, the gate of the ninth switch M9 receives the first negative voltage V output by the negative voltage generation module 101. cpThe device is reliably turned on by negative voltage drive. Its source is simultaneously connected to the common terminal of the first switch module 107 and the second switch module 108. When turned on, the potential of this common terminal can be quickly adjusted to block the parasitic capacitance coupling between the source / drain and the substrate, thereby enhancing the turn-off isolation effect. In addition, the substrate terminal of the ninth switch M9 receives the third comparison voltage V. body This ensures that when the switching module is turned on, the body diode of the ninth switch M9 is not conducting, avoiding additional leakage current. The gate of the tenth switch M10 receives the power supply voltage VDD and conducts reliably when the power supply is normal. Its source is connected to the reference voltage VSS, which stabilizes the drain potential of the ninth switch M9 in the conducting state, preventing fluctuations in the common terminal potential from affecting the turn-off reliability of the switching module. Therefore, when the power supply is normal, both the ninth switch M9 and the tenth switch M10 are in the conducting state, ensuring that VDD is not conducting. mid Connect to VSS via a low-resistance path.

[0078] It should be noted that when there is no power supply and normal power is supplied, under the action of the first resistor R1 and the second resistor R2, V cp1a With V cp2a Equipotential, V cp1b With V cp2b Equipotential. M2 and M6 conduct due to their inherent characteristics, making V... cp2a Equal to the first port voltage VA, V cp2b This equals the voltage VB at the second port, thus driving M. power1 and M power2 Conduction. Simultaneously, M1 and M5 are conducted, respectively turning on M... power1 and M power2 The body potential is connected to the first port A and the second port B to ensure correct body bias of the power transistor. At this time, VDD=0, and the tenth switch M10 is also turned off, effectively isolating VDD. mid Possible positive or negative pressure: The charge pump may not work. (V) cp =0, the ninth switch M9 effectively isolates V. mid Possible negative voltage. In summary, when the system is powered off, the circuit automatically forms a low-impedance signal path from the first port A to the second port B, ensuring the continuity of the basic audio signal.

[0079] For example, designers can select the types of the ninth switch M9 and the tenth switch M10 according to the actual situation. For instance, the ninth switch M9 can be selected as a PMOS transistor, and the tenth switch M10 can be selected as an NMOS transistor.

[0080] In one embodiment of this application, such as Figure 8 and Figure 9As shown, the first control module 105 also includes a third switch M3 and a fourth switch M4. The gates of both the third switch M3 and the fourth switch M4 are used to receive the second clamping voltage V. cp2a The third switch M3 is connected in series with the first switch M1, and the fourth switch M4 is connected in series with the second switch M2.

[0081] The second control module 106 also includes a seventh switch M7 and an eighth switch M8. The gates of both the seventh switch M7 and the eighth switch M8 are used to receive the fourth clamping voltage V. cp2b The seventh switch M7 is connected in series with the fifth switch M5, and the eighth switch M8 is connected in series with the sixth switch M6.

[0082] Specifically, regarding the improved protection against high positive voltage, when a high positive voltage may occur at the first port A or the second port B, the four control transistors—the first switch M1, the second switch M2, the fifth switch M5, and the sixth switch M6—may face voltage withstand challenges. This embodiment adds four protection transistors (the third switch M3, the fourth switch M4, the seventh switch M7, and the eighth switch M8) to share the voltage stress with the aforementioned control transistors, improving the reliability and lifespan of the circuit under extreme signal conditions without compromising the high isolation characteristics described in the previous embodiment.

[0083] For improved protection against high negative voltage, when a deep negative voltage may occur at the first port A or the second port B, the four control transistors—first switch M1, second switch M2, fifth switch M5, and sixth switch M6—may face withstand voltage problems caused by the negative voltage. This embodiment adds four protection transistors (third switch M3, fourth switch M4, seventh switch M7, and eighth switch M8) to protect the aforementioned control transistors, ensuring circuit reliability under conditions where the signal contains a large negative level. This allows the high isolation performance of this application to be stably maintained under various harsh audio signal environments.

[0084] For example, designers can select the types of the third switch M3, the fourth switch M4, the seventh switch M7, and the eighth switch M8 according to the actual situation. For instance, the third switch M3, the fourth switch M4, the seventh switch M7, and the eighth switch M8 can all be depletion-type NMOS transistors.

[0085] In summary, the beneficial effects of this application are mainly reflected in the following aspects:

[0086] (1) The isolation level of shutdown was significantly improved.

[0087] This application addresses the problem of drastic drop in turn-off isolation of traditional depletion-type MOS analog switches under high-frequency signals through innovative circuit design. Specifically, it employs two independent clamping modules to precisely control the gate voltages of the two main power transistors, physically cutting off signal transmission through the gate-drain parasitic capacitance (C) of the power transistors. gd The main leakage path is directly coupled from the first port A to the second port B. Simultaneously, by turning off specific auxiliary transistors (M9 and M10) and combining this with an internal node potential control mechanism, another critical signal leakage path through the power transistor's source / drain to the substrate's parasitic capacitance is actively cut off. This multi-parasitic path cutoff mechanism ensures that this application maintains extremely high turn-off isolation over a wide frequency range, especially at high frequencies, with performance far exceeding that of traditional single-control-path depletion-type switches.

[0088] (2) The automatic bypass function is reliable and the switching is rapid.

[0089] This invention improves turn-off isolation while perfectly preserving and enhancing the inherent automatic bypass characteristics of depletion-type MOS switches. When the system is powered off, the discharge module 110 in the control circuit can quickly release the residual negative voltage, ensuring that the main power transistors and control transistors (M1, M2, M5, and M6) automatically enter the conduction state due to their inherent characteristics, forming a low-impedance signal path. This mechanism ensures that even when the device battery is depleted or the system is powered off, the audio signal can automatically and reliably bypass the digital processing unit and be directly transmitted to the speaker, maintaining the most basic audio playback function without interruption, greatly improving the user experience. The entire switching process is fast and the state is deterministic, avoiding the risk of signal path uncertainty.

[0090] (3) The overall performance and reliability of the system have been optimized.

[0091] The beneficial effects of this application are also reflected in the improvement of the overall system performance and robustness. First, the mechanism of dynamic level tracking and on-demand generation of turn-off voltage helps reduce the power consumption of the control circuit itself compared to the traditional scheme that always outputs a maximum fixed negative voltage. Second, since dynamic negative voltage control alleviates the requirement for the absolute withstand voltage of the power transistor, it makes it possible to use standard process devices, reduce chip area and manufacturing costs. In addition, through optional protection circuit design (such as adding protection transistors on both sides of the control transistor), the withstand voltage capability of the circuit under abnormal conditions such as high positive voltage or high negative voltage at the port is effectively improved, enhancing its reliability in complex application environments.

[0092] (4) It alleviated the performance contradiction at its root.

[0093] This application cleverly alleviates the contradiction between voltage withstand requirements and turn-off isolation commonly found in traditional designs. By dynamically tracking the lowest level of the input signal to generate an appropriate gate negative voltage, reliable turn-off is ensured across the entire signal amplitude range, avoiding the need to continuously apply excessively high negative voltages to turn off negative level signals. This not only reduces the voltage withstand requirements of the power transistor but also avoids the vicious cycle of introducing larger parasitic capacitances due to the use of high-voltage devices, which in turn degrades isolation, achieving synergistic optimization of voltage withstand design and isolation performance.

[0094] In summary, the high-isolation depletion-type audio analog switch circuit provided in this application, through its innovative overall architecture and meticulous circuit design, successfully and significantly improves the key performance indicator of shutdown isolation without sacrificing the core user experience of automatic bypass. At the same time, it also brings significant additional benefits in terms of system reliability, power consumption, and cost, providing a high-performance and highly reliable audio signal path switching solution for high-end portable audio devices.

[0095] This application also discloses an audio device (such as noise-canceling headphones or Bluetooth speakers) including the aforementioned audio analog switching circuit. By integrating this audio analog switching circuit, the audio device can achieve high-isolation switching of the audio signal path under normal power supply conditions, effectively suppressing crosstalk between channels and ensuring high-fidelity audio transmission. Simultaneously, in the event of a power outage or battery depletion, the inherent characteristics of the depletion-type MOSFET automatically turn on the switching module, quickly establishing a low-impedance emergency signal bypass to ensure the continuity of basic audio functions (such as calls and music playback), handling sudden power outage scenarios without additional control. This design significantly improves the stability and reliability of the audio device in complex usage environments, and is particularly suitable for portable devices with stringent requirements for audio quality and battery life. It meets the signal purity requirements of high-end audio devices while enhancing the user experience through the emergency bypass design, improving the functional integrity and scenario adaptability of the audio device.

[0096] Since the processing and functions implemented by the audio device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned audio analog switch circuit, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0097] The above-described embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. An audio analog switching circuit, characterized in that, It includes a negative pressure generating module, a level selection module, a first clamping module, a second clamping module, a first control module, a second control module, a first switch module, and a second switch module. The negative pressure generating module is electrically connected to the first clamping module and the second clamping module, the level selection module is electrically connected to the first clamping module and the second clamping module, the first control module is electrically connected to the first clamping module and the first switch module, and the second control module is electrically connected to the second clamping module and the second switch module. When powered, the negative voltage generating module is used to output a first negative voltage; the level selection module is used to output a first comparison voltage to the first clamping module and a second comparison voltage to the second clamping module according to the first port voltage, the second port voltage and the reference voltage; the first clamping module is used to output a first clamping voltage to the first control module according to the first comparison voltage and the first negative voltage, and the first control module is used to control the first switching module to turn off according to the first clamping voltage; The second clamping module is used to output a second clamping voltage to the second control module according to the second comparison voltage and the first negative voltage, and the second control module is used to control the second switching module to turn off according to the second clamping voltage; The level selection module includes a first level selection unit and a second level selection unit. The first level selection unit is electrically connected to the first clamping module, and the second level selection unit is electrically connected to the second clamping module. The first level selection unit is used to compare the first port voltage and the reference voltage, and output the first comparison voltage to the first clamping module. The first comparison voltage is the minimum voltage between the first port voltage and the reference voltage. The second level selection unit is used to compare the second port voltage and the reference voltage, and output the second comparison voltage to the second clamping module. The second comparison voltage is the minimum voltage between the second port voltage and the reference voltage.

2. The audio analog switch circuit according to claim 1, characterized in that, The first clamping voltage includes a first clamping sub-voltage and a second clamping sub-voltage. The first clamping sub-voltage is less than the difference between the second clamping sub-voltage and a first preset voltage, and the second clamping voltage is less than the difference between the first comparison voltage and the second preset voltage. The first control module includes a first switching transistor, a second switching transistor, and a first resistor; The gate of the first switch is used to receive the first clamping sub-voltage. The source of the first switch is electrically connected to the first switch module. The drain of the first switch and the drain of the second switch are both used to receive the first port voltage. The first end of the first resistor is electrically connected to the gate of the second switch and is used to receive the first clamping sub-voltage. The second end of the first resistor is electrically connected to the source of the second switch and the first switch module respectively and is used to receive the second clamping sub-voltage. Alternatively, the gate of the first switch is used to receive the first clamping sub-voltage, the source of the first switch is electrically connected to the first switch module, the drain of the first switch and the drain of the second switch are both electrically connected to the first switch module, the second switch module and the second control module, the first end of the first resistor is electrically connected to the source of the second switch and the first switch module respectively, and is used to receive the second clamping sub-voltage, and the second end of the first resistor is electrically connected to the gate of the second switch and is used to receive the first clamping sub-voltage.

3. The audio analog switch circuit according to claim 2, characterized in that, The first control module further includes a third switch and a fourth switch. The gates of the third switch and the fourth switch are both used to receive the second clamping voltage. The third switch is connected in series with the first switch, and the fourth switch is connected in series with the second switch.

4. The audio analog switch circuit according to claim 1, characterized in that, The second clamping voltage includes a third clamping sub-voltage and a fourth clamping sub-voltage. The third clamping sub-voltage is less than the difference between the fourth clamping sub-voltage and a third preset voltage. The fourth clamping voltage is less than the difference between the second comparison voltage and a fourth preset voltage. The second control module includes a fifth switch, a sixth switch, and a second resistor; The gate of the fifth switch is used to receive the third clamping sub-voltage. The source of the fifth switch is electrically connected to the second switch module. The drain of the fifth switch and the drain of the sixth switch are both used to receive the second port voltage. The first end of the second resistor is electrically connected to the source of the sixth switch and the second switch module respectively, and is used to receive the fourth clamping sub-voltage. The second end of the second resistor is electrically connected to the gate of the sixth switch and is used to receive the third clamping sub-voltage. Alternatively, the gate of the fifth switch is used to receive the third clamping sub-voltage, the source of the fifth switch is electrically connected to the second switch module, the drain of the fifth switch and the drain of the sixth switch are both electrically connected to the first switch module, the second switch module and the first control module, the first end of the second resistor is electrically connected to the gate of the sixth switch to receive the third clamping sub-voltage, and the second end of the second resistor is electrically connected to the source of the sixth switch and the second switch module to receive the fourth clamping sub-voltage.

5. The audio analog switch circuit according to claim 4, characterized in that, The second control module further includes a seventh switch and an eighth switch. The gates of the seventh switch and the eighth switch are both used to receive the fourth clamping voltage. The seventh switch is connected in series with the fifth switch, and the eighth switch is connected in series with the sixth switch.

6. The audio analog switch circuit according to claim 1, characterized in that, The first switching module includes a first power transistor, the gate and substrate of which are electrically connected to the first control module. The drain of the first power transistor is used to receive the first port voltage, and the source of the first power transistor is electrically connected to the second switching module. The second switching module includes a second power transistor, the gate and substrate of which are electrically connected to the second control module. The drain of the second power transistor is used to receive the second port voltage, and the source of the second power transistor is electrically connected to the first switching module.

7. The audio analog switch circuit according to claim 1, characterized in that, The level selection module further includes a third level selection unit, and the audio analog switch circuit further includes a switch control module and a discharge module. The third level selection unit is electrically connected to the first switch module, the second switch module, and the switch control module, respectively. The discharge module and the switch control module are both electrically connected to the negative voltage generating module. The third level selection unit is used to compare the node voltage and the reference voltage, and output a third comparison voltage to the switch control module. The third comparison voltage is the maximum voltage between the node voltage and the reference voltage. The node voltage is the voltage at the common terminal of the first switch module and the second switch module. The switch control module is used to turn on the switch according to the power supply voltage, the third comparison voltage, and the first negative voltage. The discharge module is used to discharge the first negative voltage when the power supply is not in operation.

8. The audio analog switch circuit according to claim 7, characterized in that, The switch control module includes a ninth switch and a tenth switch. The gate of the ninth switch is used to receive the first negative voltage. The source of the ninth switch is electrically connected to the first switch module and the second switch module, respectively. The drain of the ninth switch is electrically connected to the drain of the tenth switch. The substrate of the ninth switch is electrically connected to the third level selection unit. The gate of the tenth switch is used to receive the power supply voltage, and the source of the tenth switch is used to receive the reference voltage.

9. An audio device, characterized in that, Includes the audio analog switch circuit as described in any one of claims 1-8.

Images