High-side switch circuit with ground-loss protection function

Abstract

A high-side switch circuit with a ground-loss protection function includes a ground-loss protection circuit, a reset circuit, a high-side switch drive circuit, and a high-side switch. The output terminal of the high-side switch drive circuit is connected to the control terminal of the high-side switch; the high-side switch is a semiconductor switching device. The ground-loss protection circuit has a power supply terminal, a reference terminal, an output terminal, and a reset terminal. The power supply terminal and the reference terminal of the ground-loss protection circuit are respectively connected to the power supply terminal and the reference terminal of the high-side switch drive circuit. The output terminal of the ground-loss protection circuit is connected to the control terminal of the high-side switch drive circuit, and the reset terminal of the ground-loss protection circuit is connected to the output terminal of the reset circuit. When a ground loss occurs in the high-side switch circuit, the ground-loss protection circuit outputs a turn-off control signal to the high-side switch drive circuit to turn off the high-side switch. The present invention can prevent the high-side switch from operating in the linear region when a ground loss occurs in the high-side switch circuit.

Description

Technical Field

[0001] The present invention relates to a high-side switch circuit. Background Art

[0002] Due to its advantages in reducing the harm of short circuits, reducing system costs, preventing galvanic corrosion, etc., high-side switch circuits have been widely used in the automotive field.

[0003] Figure 1 The principle block diagram of a battery charging system using a high-side switch circuit is shown. As Figure 1 shown, the input end of the high-side switch circuit 92 is connected to the output end of the DC / DC converter 91, and the output end of the high-side switch circuit 92 is connected to the positive electrode of the battery 93. The high-side switch circuit 92 can use semiconductor switches, electromagnetic relays, etc. as the high-side switch. In a specific application, the DC / DC converter 91 is a vehicle-mounted DC converter, and its output is defined as KL30, and the positive electrode of the battery 92 is defined as KL30Z. The DC / DC converter 91, the high-side switch circuit 92, the negative electrode of the battery 93, the first load 94, and the second load 95 are all connected to the body ground connection point (i.e., grounded).

[0004] Figure 1 The internal principle of the high-side switch circuit shown is as Figure 2 shown. The high-side switch circuit 92 includes a charge pump or a boost circuit 921, a high-side switch 922, a high-side switch drive circuit 923, and a controller 924. Among them, the high-side switch 922 uses an NMOS transistor. The high-side switch circuit is powered by KL30 or KL30Z. The charge pump or boost circuit 921 is used to provide a voltage that can drive the high-side switch 922. The controller 924 sends a control signal VC to the high-side switch drive circuit 923 through the sampled monitoring signal, and controls the high-side switch 922 through the high-side switch drive circuit 923.

[0005] For a high-side switch circuit using a semiconductor switch device as the high-side switch, since the reference ground of the high-side switch circuit is usually connected to the body reference ground through a connector, there is a risk of easy detachment and loss or a problem of connection failure with the body reference ground due to human operation errors in the automotive operating environment. Once the grounding is lost, the high-side switch circuit 92 is in a floating ground state. The high-side switch circuit 92 is equivalent to a variable resistor. At this time, the equivalent circuit of the battery charging system is as Figure 3 shown. KL30 is connected in series to KL30Z through the first path impedance Z1 and the second path impedance Z2 inside the product. The first path impedance Z1 and the second path impedance Z2 are connected in series and are in parallel with the high-side switch 922, which easily causes the drive of the high-side switch 922 to be uncontrollable and easily leads to the semiconductor switch device used as the high-side switch to operate in the linear region, and the prior art has not yet had a good solution to this situation. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a high-side switch circuit with a ground-loss protection function, which can prevent the high-side switch composed of semiconductor switching devices from operating in the linear region when a ground loss occurs in the high-side switch circuit.

[0007] An embodiment of the present invention provides a high-side switch circuit with a ground-loss protection function, including a high-side switch driving circuit and a high-side switch. The output end of the high-side switch driving circuit is connected to the control end of the high-side switch. The high-side switch is a semiconductor switching device. Among them, the high-side switch circuit further includes a ground-loss protection circuit and a reset circuit. The ground-loss protection circuit has a power supply end, a reference end, an output end, and a reset end. The power supply end and the reference end of the ground-loss protection circuit are respectively connected to the power supply end and the reference end of the high-side switch driving circuit. The output end of the ground-loss protection circuit is connected to the control end of the high-side switch driving circuit. The reset end of the ground-loss protection circuit is connected to the output end of the reset circuit. The ground-loss protection circuit is used to output a turn-off control signal to the high-side switch driving circuit when a ground loss occurs in the high-side switch circuit, so that the high-side switch driving circuit turns off the high-side switch and is disabled when reset by the reset circuit.

[0008] The present invention has at least the following technical effects:

[0009] The high-side switch circuit of the embodiment of the present invention is provided with a ground-loss protection circuit. When a ground loss occurs in the high-side switch circuit, the ground-loss protection circuit outputs a turn-off control signal to the high-side switch driving circuit, so that the high-side switch driving circuit turns off the high-side switch, thereby avoiding the situation that the high-side switch composed of semiconductor switching devices enters the linear working region. Brief Description of the Drawings

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0011] Figure 1 Shows a schematic block diagram of a battery charging system using a high-side switch circuit.

[0012] Figure 2 Shows a circuit schematic diagram of the high-side switch circuit.

[0013] Figure 3 Shows an equivalent circuit schematic diagram of the battery charging system when a ground loss occurs in the high-side switch circuit.

[0014] Figure 4 The circuit schematic diagram of a high-side switch circuit according to an embodiment of the present invention is shown. Detailed implementation manners

[0015] The present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0016] Please refer to Figure 4 A high-side switch circuit with a ground-loss protection function according to an embodiment of the present invention includes a ground-loss protection circuit 1, a reset circuit 2, a high-side switch driving circuit 3, and a high-side switch 4.

[0017] The output end of the high-side switch driving circuit 3 is connected to the control end of the high-side switch 4, and the high-side switch 4 is a semiconductor switching device. In this embodiment, the high-side switch is an NMOS transistor, and the gate of the NMOS transistor constitutes the control end of the high-side switch 4.

[0018] The ground-loss protection circuit 1 has a power supply terminal P1, a reference terminal N1, an output terminal, and a reset terminal. The power supply terminal P1 and the reference terminal N1 of the ground-loss protection circuit 1 are respectively connected to the power supply terminal P0 and the reference terminal N0 of the high-side switch driving circuit 3. The output terminal of the ground-loss protection circuit 1 is connected to the control end of the high-side switch driving circuit 3, and the reset terminal of the ground-loss protection circuit 1 is connected to the output terminal of the reset circuit 2. The ground-loss protection circuit 1 is used to output a turn-off control signal to the high-side switch driving circuit when a ground loss occurs in the high-side switch circuit, so that the high-side switch driving circuit turns off the high-side switch, and is disabled when reset by the reset circuit 2. When disabled, the ground-loss protection circuit 1 stops outputting the foregoing turn-off control signal, thereby releasing the protection function of the ground-loss protection circuit 1.

[0019] The ground-loss protection circuit includes a voltage stabilizing diode ZD1, a capacitor C1, a diode D2, a switching transistor Q1, a switching transistor Q2, and a switching transistor Q3.

[0020] The negative electrode of the voltage stabilizing diode ZD1 and the first end of the switching transistor Q2 are respectively connected to the power supply terminal P1 of the ground-loss protection circuit. The positive electrode of the voltage stabilizing diode ZD1 is connected to the control end of the switching transistor Q1. The first end of the switching transistor Q1 is respectively connected to the power supply terminal P1 of the ground-loss protection circuit, the first end of the capacitor C1, the second end of the switching transistor Q2, and the control end of the switching transistor Q3. The first end of the switching transistor Q3 is respectively connected to the power supply terminal P1 of the ground-loss protection circuit, the control end of the switching transistor Q2, and the negative electrode of the diode D2. The second end of the switching transistor Q1, the second end of the capacitor C1, and the second end of the switching transistor Q3 are respectively connected to the reference terminal of the ground-loss protection circuit. The positive electrode of the diode D2 is connected to the control end of the high-side switch driving circuit 3, and the positive electrode of the diode D2 constitutes the output terminal of the ground-loss protection circuit 1.

[0021] The output terminal of the reset circuit 2 is connected to the common connection point of the first end of the capacitor C1, the second end of the switching transistor Q2, and the control terminal of the switching transistor Q3. The common connection point of the first end of the capacitor C1, the second end of the switching transistor Q2, and the control terminal of the switching transistor Q3 constitutes the reset terminal of the ground-loss protection circuit 1.

[0022] When there is no ground loss in the high-side switching circuit, the zener diode ZD1 and the switching transistor Q1 are turned on, and the reset circuit establishes a discharge path for the capacitor C1 to discharge the capacitor C1, and the switching transistors Q3, Q2, and the diode D2 are turned off; when there is a ground loss in the high-side switching circuit, the zener diode ZD1 and the switching transistor Q1 are turned off, and the switching transistors Q3, Q2, and the diode D2 are turned on.

[0023] Further, the ground-loss protection circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4, and a resistor R10. The first ends of the resistors R1, R2, R4, and R10 are all connected to the power supply terminal P1 of the ground-loss protection circuit. The second end of the resistor R1 is connected to the negative electrode of the zener diode ZD1. The second end of the resistor R2 is connected to the first end of the switching transistor Q1 and the first end of the capacitor C1 respectively. The second end of the resistor R4 is connected to the first end of the switching transistor Q2. The second end of the resistor R10 is connected to the common connection point of the control terminal of the switching transistor Q2, the negative electrode of the diode D2, and the first end of the switching transistor Q3. The first end of the resistor R3 is connected to the positive electrode of the zener diode ZD1 and the control terminal of the switching transistor Q1 respectively, and the second end of the resistor R3 is connected to the reference terminal of the ground-loss protection circuit.

[0024] Optionally, the ground-loss protection circuit includes a diode D1. The positive electrode of the diode D1 is connected to the second end of the resistor R2 and the first end of the switching transistor Q1 respectively, and the negative electrode of the diode D1 is connected to the first end of the capacitor C1. The diode D1 is provided to stabilize the voltage of the capacitor C1.

[0025] In this embodiment, the switching transistors Q1 and Q3 are both NPN triodes, and the control terminal, the first end, and the second end of the switching transistors Q1 and Q3 are the base, the collector, and the emitter of the NPN triode respectively; the switching transistor Q2 is a PNP triode, and the control terminal, the first end, and the second end of the switching transistor Q2 are the base, the emitter, and the collector of the PNP triode respectively. In other embodiments, the switching transistors Q1 and Q3 are NMOS transistors, and the switching transistor Q2 is a PMOS transistor.

[0026] The reset circuit includes a switching transistor Q7 and a switching transistor Q6; the control terminal of the switching transistor Q7 is used to receive an externally input switching control signal Vrst, the first terminal of the switching transistor Q7 is connected to the control terminal of the switching transistor Q6, and the second terminal of the switching transistor Q7 is grounded; the first terminal of the switching transistor Q6 is connected to the reset terminal of the ground loss protection circuit 1, and the second terminal of the switching transistor Q6 is connected to the reference terminal of the high-side switch drive circuit. When there is no ground loss in the high-side switch circuit, the switching transistor Q7 and the switching transistor Q6 are turned on. When there is a ground loss in the high-side switch circuit, the ground of the reset circuit is also lost, and the switching transistor Q7 and the switching transistor Q6 are turned off.

[0027] Further, the reset circuit includes a resistor R7, a resistor R8, and a resistor R9; both ends of the resistor R7 are respectively connected to the first terminal and the control terminal of the switching transistor Q6, both ends of the resistor R8 are respectively connected to the control terminal of the switching transistor Q6 and the first terminal of the switching transistor Q7, one end of the resistor R9 is connected to the control terminal of the switching transistor Q7, and the other end is used to receive an externally input switching control signal Vrst.

[0028] In this embodiment, the switching transistor Q7 is an NPN triode, and the control terminal, the first terminal, and the second terminal of the switching transistor Q7 are respectively the base, the collector, and the emitter of the NPN triode; the switching transistor Q6 is a PNP triode, and the control terminal, the first terminal, and the second terminal of the switching transistor Q6 are respectively the base, the emitter, and the collector of the PNP triode. In other embodiments, the switching transistor Q7 is an NMOS transistor, and the switching transistor Q6 is a PMOS transistor.

[0029] The high-side switch drive circuit 3 includes a push-pull circuit, the input terminal of the push-pull circuit is connected to the output terminal of the ground loss protection circuit 1, and the output terminal of the push-pull circuit is connected to the control terminal of the high-side switch.

[0030] The push-pull circuit includes a switching transistor Q4, a switching transistor Q5, a resistor R5, a resistor R6, and a zener diode ZD2; the first terminal of the switching transistor Q4 and one end of the resistor R5 are both connected to the power supply terminal P0 of the high-side switch drive circuit, the control terminal of the switching transistor Q4 is respectively connected to the output terminal of the ground loss protection circuit, the second terminal of the resistor R5, the cathode of the zener diode ZD2, and the control terminal of the switching transistor O5, the second terminal of the switching transistor Q4 is connected to the first terminal of the switching transistor Q5, the first terminal of the resistor R6 is connected to the common connection point of the second terminal of the switching transistor Q4 and the first terminal of the switching transistor Q5, the second terminal of the resistor R6 is connected to the control terminal of the high-side switch, and the anode of the zener diode ZD2 and the second terminal of the switching transistor Q5 are both connected to the reference terminal N0 of the high-side switch drive circuit.

[0031] The high-side switch driving circuit further includes a resistor R19 and a switching transistor Q8. The first end of the resistor R19 is connected to the common connection point of the control end of the switching transistor Q4 and the control end of the switching transistor O5. The second end of the resistor R19 is connected to the first end of the switching transistor Q8. The second end of the switching transistor Q8 is grounded. The control end of the switching transistor Q8 is used to receive an externally input control signal Vc.

[0032] In this embodiment, the switching transistor Q4 is an NPN triode. The control end, the first end, and the second end of the switching transistor Q4 are respectively the base, the collector, and the emitter of the NPN triode. The switching transistor Q5 is a PNP triode. The control end, the first end, and the second end of the switching transistor Q5 are respectively the base, the emitter, and the collector of the PNP triode. The switching transistor Q8 is an NMOS transistor. The control end, the first end, and the second end of the switching transistor Q8 are respectively the gate, the drain, and the source of the NMOS transistor. In other embodiments, the switching transistor Q4 is an NMOS transistor, the switching transistor Q5 is a PMOS transistor, and the switching transistor Q8 is an NPN triode.

[0033] In a specific application, the high-side switch circuit is applied to the battery charging system of an automobile. The input end of the high-side switch circuit is connected to the output end (KL30) of the in-vehicle DC converter. The output end of the high-side switch circuit is connected to the positive electrode (KL30Z) of the battery. The voltage at the first end of the high-side switch 4 is KL30, the voltage at the second end of the high-side switch 4 is KL30Z, the voltage at the power supply end P0 of the high-side switch driving circuit 3 is Vsup, the voltage Vsup is the output voltage of a charge pump or a boost circuit, and the voltage at the reference end N0 of the high-side switch driving circuit 3 is KL30Z.

[0034] Under normal operating conditions, the grounding of the high-side switch circuit is not lost. The voltage Vsup and KL30Z are applied to the series branch of the resistor R1, the voltage-regulating diode ZD1, and the resistor R3. The voltage-regulating diode ZD1 operates in a voltage-regulating mode. The switching transistor Q1 is turned on. The current flows through the voltage-regulating diode ZD1 and through the base and emitter of the switching transistor Q1. At the same time, when the grounding is not lost, the single-chip microcomputer or FPGA sends a switching control signal Vrst signal to the switching transistor Q7, so that the switching transistor Q6 is turned on to discharge the capacitor C1 to achieve a reset effect. The terminal voltage of the capacitor C1 is 0 after discharging through the reset circuit 2. The base-emitter junction voltage of the switching transistor Q3 is 0, and the switching transistor Q3 is turned off and cut off. The cathode of the diode D2 is pulled up to Vsup, and the diode D2 is in an off and cut-off state. If the control signal Vc is at a low level, the output of the high-side switch driving circuit 3 is at a high level, and the high-side switch 4 is turned on. If the control signal Vc is at a high level, the output of the high-side switch driving circuit 3 is at a low level, and the high-side switch 4 is turned off.

[0035] Under abnormal working conditions, when the ground of the high-side switch circuit is lost, the voltage Vsup will decrease, the voltage difference between Vsup and KL30Z will decrease, the voltage applied to the voltage regulator diode ZD1 is not sufficient to generate enough current, the voltage regulator diode ZD1 is turned off, no current flows through the base of the switching transistor Q1, the switching transistor Q1 is turned off, the reset circuit 2 does not work, the voltage Vsup charges the capacitor C1 through the resistor R2 and the diode D1, establishing a voltage such that there is a certain voltage drop between the base and the emitter of the switching transistor Q3, the switching transistor Q3 is turned on, the base voltage of the switching transistor Q2 is pulled to KL30Z, a voltage drop is generated between the emitter and the base of the switching transistor Q2, the switching transistor Q2 is turned on, Vsup continues to charge the capacitor C1 through the resistor R4 and the switching transistor Q2, the diode D2 is turned on, the output voltage Vp of the ground-loss protection circuit 1 is pulled down to KL30Z through the diode D2, making the output of the high-side switch drive circuit 3 low level, and the high-side switch 4 is turned off.

[0036] In the case where the high-side switch circuit of this embodiment is used for the on-vehicle DC converter to charge the battery through the high-side switch circuit, by short-circuiting Z2 or reducing the impedance of Z2, the high-side switch is turned off to avoid the situation that the high-side switch enters the linear working area.

[0037] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A high-side switch circuit with a ground loss protection function, comprising a high-side switch drive circuit and a high-side switch, wherein the output terminal of the high-side switch drive circuit is connected to the control terminal of the high-side switch; the high-side switch is a semiconductor switch device; characterized in that: The high-side switch circuit further includes a ground loss protection circuit and a reset circuit; The ground loss protection circuit comprises a power supply terminal, a reference terminal, an output terminal and a reset terminal, wherein the power supply terminal and the reference terminal of the ground loss protection circuit are respectively connected to the power supply terminal and the reference terminal of the high-side switch driving circuit, the output terminal of the ground loss protection circuit is connected to the control terminal of the high-side switch driving circuit, and the reset terminal of the ground loss protection circuit is connected to the output terminal of the reset circuit; The ground loss protection circuit is configured to output a shutdown control signal to the high-side switch driving circuit when ground loss occurs in the high-side switch circuit, so that the high-side switch driving circuit turns off the high-side switch, and is disabled when reset by the reset circuit; The ground loss protection circuit includes a voltage regulator ZD1, a capacitor C1, a diode D2, a switch tube Q1, a switch tube Q2 and a switch tube Q3; The cathode of the voltage regulator tube ZD1 and the first end of the switch tube Q2 are respectively connected to the power supply terminal of the ground loss protection circuit, and the anode of the voltage regulator tube ZD1 is connected to the control terminal of the switch tube Q1; the first end of the switch tube Q1 is respectively connected to the power supply terminal of the ground loss protection circuit, the first end of the capacitor C1, the second end of the switch tube Q2, and the control terminal of the switch tube Q3; the first end of the switch tube Q3 is respectively connected to the power supply terminal of the ground loss protection circuit, the control terminal of the switch tube Q2, and the cathode of the diode D2; the second end of the switch tube Q1, the second end of the capacitor C1, and the second end of the switch tube Q3 are respectively connected to the reference terminal of the ground loss protection circuit; and the anode of the diode D2 is connected to the control terminal of the high-side switch drive circuit. The output end of the reset circuit is connected to a common point of the first end of the capacitor C1, the second end of the switch tube Q2 and the control end of the switch tube Q3; When the high-side switch circuit does not lose ground, the voltage regulator ZD1 and the switch Q1 are turned on, and the reset circuit establishes a discharge path for the capacitor C1, so that the capacitor C1 is discharged, and the switch Q3, the switch Q2 and the diode D2 are turned off; When the high-side switch circuit loses ground, the voltage regulator tube ZD1 and the switch tube Q1 are turned off, and the switch tube Q3, the switch tube Q2 and the diode D2 are turned on.

2. The high side switch circuit according to claim 1, wherein: The ground loss protection circuit includes a resistor R1, a resistor R2, a resistor R3, a resistor R4 and a resistor R10; The first ends of resistors R1, R2, R4, and R10 are all connected to the power supply terminal of the ground loss protection circuit. The second end of resistor R1 is connected to the cathode of voltage regulator diode ZD1. The second end of resistor R2 is connected to the first end of switch diode Q1 and the first end of capacitor C1, respectively. The second end of resistor R4 is connected to the first end of switch diode Q2. The second end of resistor R10 is connected to a common point of the control terminal of switch diode Q2, the cathode of diode D2, and the first end of switch diode Q3. The first end of resistor R3 is connected to the anode of voltage regulator diode ZD1 and the control terminal of switch diode Q1, respectively. The second end of resistor R3 is connected to the reference terminal of the ground loss protection circuit.

3. The high-side switch circuit according to claim 2, characterized in that, The ground loss protection circuit includes a diode D1 , wherein the anode of the diode D1 is connected to the second end of the resistor R2 and the first end of the switch Q1 , and the cathode of the diode D1 is connected to the first end of the capacitor C1 .

4. The high-side switch circuit according to claim 1, characterized in that, The switch tube Q1 and the switch tube Q3 are both NPN triodes, and the control end, the first end, and the second end of the switch tube Q1 and the switch tube Q3 are respectively the base, the collector, and the emitter of the NPN triode; The switch tube Q2 is a PNP triode, and the control end, the first end, and the second end of the switch tube Q2 are respectively the base, the emitter, and the collector of the PNP triode.

5. The high-side switch circuit according to any one of claims 1 to 4, characterized in that, The reset circuit includes a switch tube Q7 and a switch tube Q6; the control end of the switch tube Q7 is used to receive an external switch control signal, the first end of the switch tube Q7 is connected to the control end of the switch tube Q6, and the second end of the switch tube Q7 is grounded; the first end of the switch tube Q6 is connected to the reset end of the ground loss protection circuit, and the second end of the switch tube Q6 is connected to the reference end of the high-side switch drive circuit; When the high-side switch circuit does not lose ground, the switch tube Q7 and the switch tube Q6 are turned on. When the high-side switch circuit loses ground, the switch tube Q7 and the switch tube Q6 are turned off.

6. The high side switch circuit according to claim 5, characterized in that: The reset circuit includes a resistor R7, a resistor R8, and a resistor R9; two ends of the resistor R7 are respectively connected to the first end of the switch tube Q6 and the control end of the switch tube Q6, two ends of the resistor R8 are respectively connected to the control end of the switch tube Q6 and the first end of the switch tube Q7, one end of the resistor R9 is connected to the control end of the switch tube Q7, and the other end is used to receive an external input switch control signal; The switch tube Q7 is an NPN transistor, and the control end, the first end, and the second end of the switch tube Q7 are the base, the collector, and the emitter of the NPN transistor respectively; The switch tube Q6 is a PNP triode, and the control end, the first end, and the second end of the switch tube Q6 are respectively the base, the emitter, and the collector of the PNP triode.

7. The high side switch circuit according to claim 1, wherein: The high-side switch driving circuit includes a push-pull circuit, an input end of the push-pull circuit is connected to an output end of the ground loss protection circuit, and an output end of the push-pull circuit is connected to a control end of the high-side switch.

8. The high side switch circuit according to claim 7, wherein: The push-pull circuit includes a switch tube Q4, a switch tube Q5, a resistor R5, a resistor R6 and a voltage regulator tube ZD2; a first end of the switch tube Q4 and one end of the resistor R5 are both connected to the power supply end of the high-side switch drive circuit, a control end of the switch tube Q4 is respectively connected to the output end of the ground loss protection circuit, the second end of the resistor R5, the cathode of the voltage regulator tube ZD2 and the control end of the switch tube O5, a second end of the switch tube Q4 is connected to the first end of the switch tube Q5, a first end of the resistor R6 is connected to a common point between the second end of the switch tube Q4 and the first end of the switch tube Q5, and a second end of the resistor R6 is connected to the control end of the high-side switch; an anode of the voltage regulator tube ZD2 and a second end of the switch tube Q5 are both connected to the reference end of the high-side switch drive circuit; The high-side switch driving circuit further includes a resistor R19 and a switching transistor Q8. The first end of the resistor R19 is connected to the common connection point of the control end of the switching transistor Q4 and the control end of the switching transistor O5. The second end of the resistor R19 is connected to the first end of the switching transistor Q8. The second end of the switching transistor Q8 is grounded. The control end of the switching transistor Q8 is used to receive an externally input control signal.

9. The high side switch circuit according to claim 1, wherein: The high-side switch is an NMOS transistor, and the gate of the NMOS transistor constitutes the control end of the high-side switch.

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