Fault protection circuit, vehicle-mounted power amplifier device and vehicle

Abstract

The utility model provides a fault protection circuit, a vehicle-mounted power amplifier device and a vehicle. The fault protection circuit comprises a power supply end which is used for being connected to a power supply to obtain power supply voltage; the load end is used for being connected to a load to provide power supply voltage for the load; the first end of the first switch is connected to a power supply end, the first end of the second switch is connected to a load end, and the second end of the first switch is connected with the second end of the second switch; wherein the first switch is provided with a first body diode, and the second switch is provided with a second body diode; the driving module is connected to the control end of the first switch and the control end of the second switch, and the driving module is configured to output a driving signal. When the first switch and the second switch are controlled to be disconnected due to a fault working condition, due to the existence of two back-to-back body diodes, current cannot circulate between a power supply end and a load end, and forward isolation and reverse isolation under different fault working conditions are further realized.

Description

Technical Field

[0001] The disclosed embodiments of the present application relate to the technical field of vehicle-mounted equipment, and more specifically, to a fault protection circuit, a vehicle-mounted power amplifier device and a vehicle. Background Art

[0002] In vehicle manufacturing, in order to avoid short circuits that may occur at the input and output ends of vehicle components and in the load circuit, it is necessary to add short-circuit protection function at the input of the power interface. Especially in the field of vehicle amplifiers, since it is necessary to provide short-term high current to drive subwoofers and high-power speakers, large-capacity capacitors will be added to the power path.

[0003] During use, fault conditions such as the power supply being connected to the negative pole or the load being short-circuited to the ground may occur, causing the large-capacity capacitor to discharge reversely to the power supply or the power supply to instantly charge the large-capacity capacitor, thereby causing product damage. The current power supply protection circuit can usually only cut off the circuit under one of the fault conditions, that is, it can only achieve forward isolation or reverse isolation, so the protection effect is not good.

[0004] Therefore, how to achieve forward isolation and reverse isolation respectively under different fault conditions has become a problem that needs to be solved urgently. Utility Model Content

[0005] According to the embodiments of the present application, the present application proposes a fault protection circuit, a vehicle-mounted power amplifier device and a vehicle, so as to respectively achieve forward isolation and reverse isolation under different fault conditions.

[0006] According to one aspect of the present application, an exemplary fault protection circuit is disclosed, including a power supply end, a load end, a first switch, a second switch and a driving module; the power supply end is used to be connected to a power supply to obtain a power supply voltage; the load end is used to be connected to a load to provide the power supply voltage to the load; the first end of the first switch is connected to the power supply end, the first end of the second switch is connected to the load end, and the second end of the first switch is connected to the second end of the second switch; wherein the first switch has a first body diode, the cathode of the first body diode is connected to the first end of the first switch, the anode of the first body diode is connected to the second end of the first switch, and the second switch has a second body diode, the cathode of the second body diode is connected to the first end of the second switch, and the anode of the second body diode is connected to the second end of the second switch; the driving module is connected to the control end of the first switch and the control end of the second switch, and the driving module is configured to output a driving signal.

[0007] According to a second aspect of the present application, a vehicle-mounted power amplifier device is provided, comprising a power supply, a power amplifier, and the fault protection circuit of the first aspect described above.

[0008] According to a third aspect of the present application, a vehicle is provided, comprising the vehicle-mounted power amplifier device according to the second aspect.

[0009] In the above scheme, a first switch and a second switch are arranged between the power supply end and the load end, and a first body diode is connected in parallel at both ends of the first switch, and a second body diode is connected in parallel at both ends of the second switch, and the first body diode and the second body diode are connected back to back. The driving module is used to output a driving signal to drive the first switch and the second switch to be disconnected or turned on; therefore, when the first switch and the second switch are controlled to be disconnected due to a fault condition, due to the existence of two back-to-back body diodes, the current cannot flow between the power supply end and the load end, thereby achieving forward isolation and reverse isolation under different fault conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The present application will be further described below in conjunction with the accompanying drawings and implementation methods, in which:

[0011] Figure 1 It is a schematic diagram of a framework of an embodiment of a fault protection circuit of the present application;

[0012] Figure 2 is a schematic diagram of a framework of another embodiment of the fault protection circuit of the present application;

[0013] Figure 3 It is a schematic diagram of the framework of an embodiment of a boost unit of the present application;

[0014] Figure 4 It is a schematic diagram of the circuit structure of the bootstrap module of this application;

[0015] Figure 5 It is a schematic diagram of a framework of another embodiment of the fault protection circuit of the present application;

[0016] Figure 6 is a circuit structure diagram of an embodiment of a fault protection circuit of the present application;

[0017] Figure 7 It is a schematic diagram of the framework of an embodiment of the vehicle-mounted power amplifier device of the present application;

[0018] Figure 8 It is a schematic diagram of the framework of a vehicle embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the technical solution of the present application, the technical solution of the present application is further described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0020] The first aspect of the present application provides a fault protection circuit. Figure 1 , Figure 1It is a schematic diagram of a framework of an embodiment of a fault protection circuit of the present application; specifically, the fault protection circuit includes a power supply terminal BATT, a load terminal BATT_FILT, a first switch, a second switch and a driving module 100; the power supply terminal BATT is used to connect to a power supply to obtain a power supply voltage; the load terminal BATT_FILT is used to connect to a load to provide a power supply voltage to the load; the first end of the first switch is connected to the power supply terminal BATT, the first end of the second switch is connected to the load terminal BATT_FILT, and the second end of the first switch is connected to the second end of the second switch; wherein the first switch has a first body diode D1, the cathode of the first body diode D1 is connected to the first end of the first switch, the anode of the first body diode D1 is connected to the second end of the first switch, the second switch has a second body diode D2, the cathode of the second body diode D2 is connected to the first end of the second switch, and the anode of the second body diode D2 is connected to the second end of the second switch; the driving module 100 is connected to the control end of the first switch and the control end of the second switch, and the driving module 100 is configured to output a driving signal.

[0021] The first switch and the second switch may be metal oxide semiconductor field effect transistors (MOSFETs), the first switch and the second switch are connected back to back, that is, the source of the first switch and the source of the second switch are connected, the drain of the first switch is connected to the power supply terminal BATT, the drain of the second switch is connected to the load terminal BATT_FILT, and the two body diodes of the first switch and the second switch are also connected back to back to each other. In other embodiments, the first switch and the second switch may also be controllable semiconductor transistors such as triodes.

[0022] The gates of the first switch and the second switch are connected to the driving module 100. When the driving module 100 outputs a first driving signal, the first switch and the second switch are disconnected. When the driving module 100 outputs a second driving signal, the first switch and the second switch are turned on. The first driving signal may be a low level signal, and the second driving signal may be a high level signal.

[0023] In this embodiment, a first switch and a second switch are provided between the power supply terminal BATT and the load terminal BATT_FILT, and a first body diode D1 is connected in parallel at both ends of the first switch, and a second body diode D2 is connected in parallel at both ends of the second switch, and the first body diode D1 and the second body diode D2 are connected back to back. The driving module 100 is used to output a driving signal to drive the first switch and the second switch to be disconnected or turned on; therefore, when the first switch and the second switch are controlled to be disconnected due to a fault condition, due to the existence of two back-to-back body diodes, the current cannot flow between the power supply terminal BATT and the load terminal BATT_FILT, thereby achieving forward isolation and reverse isolation under different fault conditions.

[0024] In some embodiments, please refer to Figure 2 , Figure 2 It is a framework diagram of another embodiment of the fault protection circuit of the present application; the driving module 100 may include a boost unit 110 and a control unit 120; the input end of the boost unit 110 is connected to the power supply end BATT, and the output end is connected to the control end of the first switch and the control end of the second switch; the control unit 120 is connected to the power supply and is configured to control the power supply to be powered off when a load fault occurs.

[0025] The input end of the boost unit 110 is connected to the power supply voltage to increase the power supply voltage to stably drive the first switch and the second switch to be turned on or off. The control unit 120 can be implemented by a single-chip microcomputer, and the control unit 120 can be connected to the load end BATT_FILT to detect the load end BATT_FILT voltage; for example, when the load end BATT_FILT is short-circuited and directly grounded, the control unit 120 detects that the load end BATT_FILT voltage is abnormal, and outputs a control signal to the power supply to power off the power supply, thereby causing the driving module 100 to lose the voltage source, and the driving module 100 outputs a first drive signal to control the first switch and the second switch to be turned off to prevent the power supply voltage from instantaneously charging the large-capacity capacitor.

[0026] In this embodiment, the power supply voltage is increased by the boost unit 110 to generate a drive signal, so that the first switch and the second switch can be stably turned on or off; at the same time, since the drive module 100 is connected to the power supply terminal BATT to obtain the power supply voltage, when the power supply terminal BATT is not connected to the power supply, for example, when the power supply terminal BATT is short-circuited to the ground, the drive module 100 can automatically output the first drive signal to control the first switch and the second switch to be disconnected, thereby achieving short-circuit protection while reducing the circuit control logic and cost; the control unit 120 detects the load terminal BATT_FILT voltage and outputs a control signal to the power supply, and controls the power supply to be powered off when the load terminal BATT_FILT is short-circuited to the ground, and the control unit 120 can be implemented by a single-chip microcomputer, thereby reducing the circuit implementation cost.

[0027] In some embodiments, please refer to Figure 3 , Figure 3 It is a framework diagram of an embodiment of a boost unit 110 of the present application; the boost unit 110 may include a pulse output device 112 and a bootstrap module 111; the pulse output device 112 is used to output a pulse voltage; the bootstrap module 111 includes a power supply voltage input terminal IP, a pulse voltage input terminal IW and a drive signal output terminal, the power supply voltage input terminal IP is used to connect to the power supply terminal BATT, the pulse voltage input terminal IW is connected to the pulse output device 112, and the drive signal output terminal is connected to the control terminals of the first switch and the second switch; the bootstrap module 111 generates a drive signal based on the power supply voltage and the pulse voltage.

[0028] It should be noted that the pulse voltage may be a pulse width modulation signal (PWM).

[0029] In some embodiments, please refer to Figure 4 , Figure 4 It is a circuit structure diagram of the bootstrap module 111 of the present application; the bootstrap module 111 may include at least one bootstrap submodule 111a, including a bootstrap capacitor, a first diode, and a second diode; the cathode of the first diode is connected to the anode of the second diode, the anode of the first diode is used to access the upper voltage, and the cathode of the second diode is used to output the voltage, wherein, when the bootstrap submodule 111a is the first bootstrap submodule 111a, the upper voltage is the power supply voltage; when the bootstrap submodule 111a is not the first bootstrap submodule 111a, the upper voltage is the voltage output by the previous bootstrap submodule 111a; one end of the bootstrap capacitor is connected to the pulse voltage input terminal IW, and the other end is connected to the cathode of the first diode.

[0030] like Figure 4 As shown, the bootstrap module 111 may include two bootstrap submodules 111a; in other embodiments, the bootstrap module 111 may include any other number of bootstrap submodules 111a. In practical applications, the number of bootstrap submodules 111a can be designed as needed, and this application does not limit it. The bootstrap module 111 uses a number of bootstrap capacitors and diodes to pass through Figure 4 The connection method shown is connected to each other, and a pulse voltage is connected to the pulse voltage input terminal IW. When the pulse voltage is in a high level state, the voltage across the capacitor cannot change suddenly, so the voltage at the other end of the bootstrap capacitor connected to the pulse voltage input terminal IW is increased; when the pulse voltage is in a low level state, the diode cannot conduct in the reverse direction, so the bootstrap capacitor cannot discharge to the pulse voltage input terminal IW.

[0031] In this embodiment, the bootstrap module 111 can achieve voltage boosting through a number of diodes and capacitors without the need for a voltage boosting chip for control, thereby further reducing circuit cost; at the same time, using simple components instead of a voltage boosting chip for control can also improve the reliability of the circuit voltage boosting effect.

[0032] In some embodiments, the pulse output device 112 may be a Schmitt trigger, which further reduces circuit cost.

[0033] In some embodiments, the fault protection circuit may further include an isolation module. The first end of the isolation module is connected to the input end of the boost unit, and the second end is connected to the power supply end BATT; the control end of the isolation module is connected to the isolation control power supply; wherein the isolation control power supply is configured to output a first isolation control signal after the power supply is powered on to control the conduction between the first end and the second end; and output a second isolation control signal after the power supply is powered off to control the disconnection between the first end and the second end.

[0034] The isolation control power supply can be connected to the power terminal BATT to generate a 5V voltage as a first isolation control signal after the power supply is powered on, so as to control the conduction between the first terminal and the second terminal of the isolation module.

[0035] In this embodiment, the power supply is isolated from the boost unit by the isolation module, which can reduce the impact of the power supply failure on the boost unit and the first switch and the second switch, thereby improving the stability of the fault protection circuit.

[0036] In some embodiments, the fault protection circuit may further include a voltage limiting unit 200, see Figure 5 , Figure 5 It is a framework diagram of another embodiment of the fault protection circuit of the present application; the first end of the voltage limiting unit 200 is connected to the second end of the second switch, and the second end is connected to the control end of the second switch; the voltage limiting unit 200 is configured to be electrically conductive under power supply, and the absolute value of the voltage across the voltage limiting unit 200 is less than the absolute value of the conduction voltage threshold of the first switch and the second switch, so as to control the first switch and the second switch to be disconnected.

[0037] When the power supply is turned off, the driving module 100 may not be able to be powered off in time, resulting in the first switch and the second switch being unable to be disconnected immediately. At this time, the voltage limiting unit 200 is turned on, so that the voltage between the second end and the control end of the first switch and the second switch is limited to the voltage across the voltage limiting unit 200, thereby enabling the first switch and the second switch to be disconnected immediately.

[0038] In this embodiment, the voltage limiting unit 200 enables the first switch and the second switch to be disconnected immediately after the power supply is turned off, thereby improving the fault protection effect and the reliability of the fault protection circuit.

[0039] In some embodiments, the fault protection circuit may further include a slow start module connected to the output end of the boost unit 110 , and the slow start module is used to reduce the impact current generated after the power supply is powered on.

[0040] Please refer to Figure 6 , Figure 6 is a circuit structure diagram of an embodiment of a fault protection circuit of the present application; Figure 6As shown, the power supply terminal BATT is grounded through the capacitor C1 and the capacitor C8; the power supply terminal BATT is connected to the drain of the first switch Q1, the source of the first switch Q1 is connected to the source of the second switch, the drain of the second switch is connected to the load terminal BATT_FILT after filtering through the capacitors C2, C3, C7, C6 and the inductor L1, and the load terminal BATT_FILT is also grounded through the large-capacity capacitor CP1; the driving module 100 is connected to the power supply terminal BATT through the isolation module, the pulse output device 112 is connected to the capacitor C9 and one end of the capacitor C11 through the resistor R9 to provide a pulse voltage thereto, after the driving module 100 is connected to the power supply voltage, it is grounded through the capacitor C14, and is connected to the driving signal output terminal V_CHRG through the diode D4, the diode D5, the diode D7, and the diode D6 in sequence; one end of the capacitor C9 and the capacitor C11 are respectively connected to the cathode of the diode D4 and the cathode of the diode D7, and then under the action of the power supply voltage and the pulse voltage, a second driving signal higher than the power supply voltage is output to control the first switch and the second switch to be stably turned on.

[0041] When a fault such as the power supply end BATT short-circuited to ground or the load end BATT_FILT short-circuited to ground occurs, the driving module 100 outputs a first driving signal, and the absolute value of the first driving signal is less than the absolute value of the conduction threshold voltage of the first switch and the second switch, thereby turning off the first switch and the second switch. Due to the body diodes of the first switch and the second switch, the current cannot form a path in the direction from the load end BATT_FILT to the power supply end BATT or from the power supply end BATT to the load end BATT_FILT, thereby achieving reverse isolation and forward isolation effects.

[0042] The gate and source of the first switch Q1 are connected via a diode D3, a capacitor C5, and a resistor R2, respectively. The gate and source of the second switch Q2 are connected via a diode D2, a capacitor C4, and a resistor R1, respectively, to achieve isolation and filtering effects between the gate and the source.

[0043] The voltage limiting unit 200 includes a transistor T1 and a diode D1. The voltage limiting unit 200 is connected between the gate-source of the first switch Q1 and the second switch Q2. When the power supply is powered off, the drive signal output terminal V_CHRG cannot be powered off immediately due to the capacitor in the driving module 100. At this time, the transistor T1 is turned on, and the gate-source voltage drop of the first switch Q1 and the second switch Q2 is limited to the voltage across the voltage limiting unit 200. The voltage across the voltage limiting unit 200 is extremely small, so that the first switch Q1 and the second switch Q2 are immediately turned off.

[0044] The resistor R3 and the resistor R4 are respectively connected between the driving signal output terminal V_CHRG and the gate of the second switch Q2 and the gate of the first switch Q1 to limit the gate voltage.

[0045] The slow start module may include transistors Q3 and Q4, the emitters of transistors Q3 and Q4 are connected to the drive signal output terminal V_CHRG, the collector of transistor Q3 is connected to the base of Q4 and grounded through resistor R6, and Q4 is grounded through capacitor C13 and diode D8. Through the slow start module, after the power supply is powered on, the impact current can be reduced and the power supply of the fault protection circuit can be delayed to prevent the circuit from being damaged due to the sudden power-on of the power supply, thereby improving the circuit reliability.

[0046] The second aspect of the present application provides a vehicle-mounted power amplifier device, please refer to Figure 7 , Figure 7 It is a schematic diagram of the framework of an embodiment of the vehicle-mounted power amplifier device of the present application. Specifically, the vehicle-mounted power amplifier device 700 includes a power supply 710, a power amplifier 730, and the fault protection circuit 720 of the first aspect mentioned above.

[0047] In the above scheme, a first switch and a second switch are arranged between the power supply end and the load end, and a first body diode is connected in parallel at both ends of the first switch, and a second body diode is connected in parallel at both ends of the second switch, and the first body diode and the second body diode are connected back to back. The driving module is used to output a driving signal to drive the first switch and the second switch to be disconnected or turned on; therefore, when the first switch and the second switch are controlled to be disconnected due to a fault condition, due to the existence of two back-to-back body diodes, the current cannot flow between the power supply end and the load end, thereby achieving forward isolation and reverse isolation under different fault conditions.

[0048] According to a third aspect of the present application, a vehicle 800 is provided, see Figure 8 , Figure 8 It is a schematic framework diagram of a vehicle embodiment of the present application, wherein the vehicle 800 includes the vehicle-mounted power amplifier device 700 of the second aspect described above.

[0049] In the above scheme, a first switch and a second switch are arranged between the power supply end and the load end, and a first body diode is connected in parallel at both ends of the first switch, and a second body diode is connected in parallel at both ends of the second switch, and the first body diode and the second body diode are connected back to back. The driving module is used to output a driving signal to drive the first switch and the second switch to be disconnected or turned on; therefore, when the first switch and the second switch are controlled to be disconnected due to a fault condition, due to the existence of two back-to-back body diodes, the current cannot flow between the power supply end and the load end, thereby achieving forward isolation and reverse isolation under different fault conditions.

[0050] It is easy for a person skilled in the art to know that many modifications and changes can be made to the device and method while maintaining the teaching content of the present application. Therefore, the above disclosure should be considered as limited only by the scope of the appended claims.

Claims

1. A fault protection circuit, characterized in that: include: A power terminal, used for connecting to a power source to obtain a power supply voltage; A load terminal, used for connecting to a load to provide the power supply voltage to the load; a first switch and a second switch, wherein a first end of the first switch is connected to the power supply end, a first end of the second switch is connected to the load end, and a second end of the first switch is connected to a second end of the second switch; wherein the first switch has a first body diode, a cathode of the first body diode is connected to the first end of the first switch, an anode of the first body diode is connected to the second end of the first switch, and the second switch has a second body diode, a cathode of the second body diode is connected to the first end of the second switch, and an anode of the second body diode is connected to the second end of the second switch; A driving module is connected to the control end of the first switch and the control end of the second switch, and the driving module is configured to output a driving signal.

2. The circuit according to claim 1, characterized in that The driving module comprises: A boost unit, wherein an input end of the boost unit is connected to the power supply end, and an output end of the boost unit is connected to a control end of the first switch and a control end of the second switch; A control unit is connected to the power supply, and the control unit is configured to control the power supply to be powered off when the load fails.

3. The circuit according to claim 2, characterized in that The boost unit comprises: Pulse output device, outputting pulse voltage; The bootstrap module includes a power supply voltage input terminal, a pulse voltage input terminal and a drive signal output terminal, wherein the power supply voltage input terminal is used to be connected to the power supply terminal, the pulse voltage input terminal is connected to the pulse output device, and the drive signal output terminal is connected to the control terminals of the first switch and the second switch; the bootstrap module generates the drive signal based on the power supply voltage and the pulse voltage.

4. The circuit according to claim 3, characterized in that The bootstrap module comprises: At least one bootstrap submodule comprises a bootstrap capacitor, a first diode and a second diode; the cathode of the first diode is connected to the anode of the second diode, the anode of the first diode is used to access the upper voltage, and the cathode of the second diode is used to output the voltage, wherein when the bootstrap submodule is the first bootstrap submodule, the upper voltage is the power supply voltage; when the bootstrap submodule is not the first bootstrap submodule, the upper voltage is the voltage output by the previous bootstrap submodule; one end of the bootstrap capacitor is connected to the pulse voltage input end, and the other end is connected to the cathode of the first diode.

5. The circuit according to claim 4, characterized in that The pulse output device is a Schmitt trigger.

6. The circuit according to any one of claims 2 to 5, characterized in that: Also includes: An isolation module, a first end of which is connected to the input end of the boost unit, and a second end of which is connected to the power supply end; The control end of the isolation module is connected to an isolation control power supply; Among them, the isolation control power supply is configured to output a first isolation control signal after the power supply is powered on to control conduction between the first end and the second end; and output a second isolation control signal after the power supply is powered off to control disconnection between the first end and the second end.

7. The circuit according to any one of claims 2 to 5, characterized in that: Also includes: A voltage limiting unit, wherein a first end is connected to the second end of the second switch, and a second end is connected to the control end of the second switch; the voltage limiting unit is configured to be turned on after the power supply is powered off, and the absolute value of the voltage across the voltage limiting unit is less than the absolute value of the turn-on voltage threshold of the first switch and the second switch, so as to control the first switch and the second switch to be disconnected.

8. The circuit according to any one of claims 2 to 5, characterized in that: Also includes: A slow start module is connected to the output end of the boost unit, and is used to reduce the impact current generated after the power supply is powered on.

9. A vehicle-mounted power amplifier device, comprising a power supply and a power amplifier, characterized in that: It also includes the fault protection circuit as described in any one of claims 1 to 8.

10. A vehicle, characterized in that: It includes the vehicle-mounted power amplifier device as claimed in claim 9.

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