Low-voltage motor driving circuit

Abstract

The utility model provides a low-voltage motor drive circuit. The low-voltage motor drive circuit comprises a first clamping module, a second clamping module, a boost module, an LDO module, a drive module, an electric control switch group and a signal generation module. The input end of the boosting module and the input end of the second clamping module are grounded through the first clamping module and are jointly connected to a power supply voltage VM, and the feedback end of the second clamping module is connected with the output end of the boosting module; the output end of the boosting module is connected with the input end of the LDO module and the first input end of the driving module, and the output end of the LDO module is connected with the second input end of the driving module; the output end of the signal generation module is connected with the driving control end of the driving module, and the output end of the driving module is connected with the input end of the electric control switch group. According to the utility model, the problems of how to stably drive the motor in a low-voltage scene and how to ensure the safety and stability of the circuit in a high-voltage scene in the prior art are solved.

Description

Technical Field

[0001] The utility model relates to the technical field of motor control, in particular to a low-voltage motor drive circuit. Background Art

[0002] As electronic devices continue to develop towards miniaturization and low power consumption, the demand for motor drive solutions under low power supply voltage is becoming increasingly urgent. However, most of the mainstream motor drive technologies on the market are designed for power supply voltages above 3V, which means that in scenarios with power supply voltages below this range, especially below 1.8V, traditional drive technologies may not be able to provide reliable drive effects.

[0003] To address this challenge, existing solutions usually address it by boosting the low power supply voltage. Although this method can enable the motor to operate at a low voltage, it may cause new safety hazards such as overload or thermal runaway of circuit components when the power supply voltage is high. In view of the above problems, it is necessary to propose a motor drive circuit solution that can adapt to a wide range of power supplies, especially low voltage power supplies. Utility Model Content

[0004] In view of the deficiencies in the prior art, the utility model provides a low-voltage motor drive circuit, which solves the problem in the prior art of how to achieve wide-range power supply, especially the problem of safely driving the motor under low voltage power supply.

[0005] The embodiment of the utility model provides a low-voltage motor drive circuit, comprising: a first clamping module, a second clamping module, a boost module, an LDO module, a drive module, an electric control switch group and a signal generation module;

[0006] The input end of the boost module and the input end of the second clamp module are grounded through the first clamp module and are connected to the power supply voltage VM, and the feedback end of the second clamp module is connected to the output end of the boost module;

[0007] The output end of the boost module is connected to the input end of the LDO module and the first input end of the driving module, and the output end of the LDO module is connected to the second input end of the driving module;

[0008] The output end of the signal generating module is connected to the driving control end of the driving module, and the output end of the driving module is connected to the input end of the electric control switch group.

[0009] As a further solution, the boost module includes an RC oscillator circuit, a frequency division unit and a charge pump boost unit;

[0010] The output end of the RC oscillator circuit is connected to the input end of the frequency division unit;

[0011] The output end of the frequency dividing unit is connected to the second input end of the charge pump boost unit;

[0012] The first input terminal of the charge pump boost unit is connected to the power supply voltage VM.

[0013] As a further solution, the first clamping module includes a first voltage regulator tube and a first resistor, the cathode of the first voltage regulator tube is connected to the input power supply voltage VM, and the anode of the first voltage regulator tube is grounded through the first resistor.

[0014] As a further solution, the second clamping module includes a second voltage regulator tube, the positive electrode of the second voltage regulator tube is connected to the input end of the boost module, and the negative electrode of the second voltage regulator tube is connected to the output end of the boost module.

[0015] As a further solution, the charge pump boost unit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a first inverter, a second inverter, a third inverter, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a third voltage regulator and a fourth voltage regulator; wherein the first inverter, the second inverter and the third inverter each include an input terminal, an output terminal, a power supply terminal and a reference ground terminal, the power supply terminals of the first inverter, the second inverter and the third inverter are all connected to the power supply voltage VM, and the reference ground terminals are all floating;

[0016] The anode of the first diode is connected to the anode of the second diode, and they are connected to the power supply voltage VM as the first input terminal of the charge pump boost unit, and the cathode of the first diode is connected to the anode of the third diode and one end of the first capacitor;

[0017] The cathode of the second diode is connected to the anode of the fourth diode and one end of the second capacitor;

[0018] After the cathode of the third diode is connected to the cathode of the fourth diode, it is also connected to the anode of the fifth diode and the anode of the sixth diode;

[0019] The cathode of the fifth diode is connected to the anode of the seventh diode and one end of the third capacitor;

[0020] The cathode of the sixth diode is connected to the anode of the eighth diode and one end of the fourth capacitor;

[0021] After the cathode of the seventh diode is connected to the cathode of the eighth diode, they serve together as the output end of the charge pump boost unit to output the boosted voltage;

[0022] The input end of the first inverter is connected to the input end of the second inverter, and together they serve as the second input end of the charge pump boost unit and are connected to the output end of the frequency division unit;

[0023] The output end of the first inverter is connected to the other end of the first capacitor and the other end of the third capacitor, the negative electrode of the third voltage regulator is connected to one end of the third capacitor, and the positive electrode of the third voltage regulator is connected to the other end of the third capacitor;

[0024] The output end of the second inverter is connected to the input end of the third inverter, the output end of the third inverter is connected to the other end of the second capacitor and the other end of the fourth capacitor, the negative electrode of the fourth voltage regulator is connected to one end of the fourth capacitor, and the positive electrode of the fourth voltage regulator is connected to the other end of the fourth capacitor.

[0025] As a further solution, the RC oscillator circuit includes a second resistor, a third resistor, a fourth inverter and a fifth capacitor; wherein the fourth inverter includes an input terminal, an output terminal, a power supply terminal and a reference ground terminal;

[0026] One end of the second resistor and the input end of the fourth inverter are connected to one end of the fifth capacitor, and the other end of the fifth capacitor is grounded through the third resistor; the power supply end of the fourth inverter is connected to the power supply voltage VM, the reference ground end of the fourth inverter is floating, and the output end of the fourth inverter is connected to the other end of the second resistor.

[0027] As a further solution, the frequency dividing unit is set by a frequency divider, and the frequency divider includes a signal receiving end, a trigger end, an output end, a power supply end and a reference ground end; the signal receiving end of the frequency divider is connected to the output end of the RC oscillation circuit, the power supply end of the frequency divider is connected to the power supply voltage VM, the reference ground end of the frequency divider is floating, and the output end of the frequency divider is connected to the trigger end.

[0028] As a further solution, the signal generating module includes an oscillator and a signal processing module, the first input end of the signal processing module is connected to the oscillator, the second input end of the signal processing module is used to receive an external level signal, and the output end of the signal processing module is connected to the driving control end of the driving module.

[0029] As a further solution, the electronically controlled switch group includes a first MOS tube and a second MOS tube;

[0030] The drain of the first MOS transistor is connected to the power supply voltage VM, the gate of the first MOS transistor is connected to the first output terminal of the driving module, and the gate of the second MOS transistor is connected to the second output terminal of the driving module;

[0031] The source of the first MOS tube is connected to the drain of the second MOS tube and serves together as an output end of the electric control switch group, and the source of the second MOS tube is grounded.

[0032] Compared with the prior art, the utility model has the following beneficial effects:

[0033] When the pulse signal generated by the oscillation circuit is divided, a square wave signal of a specific frequency will be generated, which is output to the next inverter. The cascaded two-stage inverter alternately generates high and low level outputs according to the square wave signal to drive the capacitor to charge and discharge, thereby achieving a three-fold boost of the input power supply. At the same time, this solution can achieve a three-fold boost and output when the input power supply voltage is low, and when the power supply voltage rises to a certain level, the clamping module will be triggered to clamp the voltage to prevent the boosted voltage from being too high. It can not only stably drive the motor in a low-voltage scenario, but also stabilize the voltage in a high-voltage scenario, ensuring the safety and stability of the circuit. Compared with the existing technology, this solution can adapt to a wide range of power supply, especially motor drive under low-voltage power supply, and is suitable for a wider range of motor drive applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 A schematic diagram of the structure of a low-voltage motor drive circuit provided by an embodiment of the utility model;

[0035] Figure 2 A circuit schematic diagram of a boost module provided in an embodiment of the utility model;

[0036] Figure 3 A circuit structure diagram of a first clamping module provided in an embodiment of the utility model;

[0037] Figure 4 A circuit structure diagram of a boost module and a clamp module in a low-voltage motor drive circuit is provided for an embodiment of the utility model;

[0038] Figure 5 A schematic diagram of the structure of a signal generating module provided in an embodiment of the utility model. DETAILED DESCRIPTION

[0039] The technical solution of the present utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0040] like Figure 1 As shown, the embodiment of the utility model provides a low-voltage motor drive circuit, including: a first clamping module 100, a second clamping module 200, a boost module 300, an LDO module 400, a drive module 500, an electric control switch group 600 and a signal generation module 700;

[0041] The input end of the boost module 300 and the input end of the second clamp module 200 are grounded through the first clamp module 100 and are connected to the power supply voltage VM. The feedback end of the second clamp module 200 is connected to the output end of the boost module 300. The output end of the boost module 300 is connected to the input end of the LDO module 400 and the first input end of the driving module 500. The output end of the LDO module 400 is connected to the second input end of the driving module 500.

[0042] The output end of the signal generating module 700 is connected to the driving control end of the driving module 500 , and the output end of the driving module 500 is connected to the input end of the electric control switch group 600 .

[0043] The working principle of this embodiment is:

[0044] If the power supply voltage VM received by the boost module 300 is a high voltage power supply that is higher than the voltage regulation working voltage of the first clamp module 100, the first clamp module 100 clamps the power supply voltage VM to the first clamp voltage, the boost module 300 boosts the power supply voltage VM, and the output boost voltage is clamped to the second clamp voltage by the second clamp module 200. For the ground terminal, the boost voltage output by the boost module 300 is the sum of the power supply voltage VM and the second clamp voltage.

[0045] If the power supply voltage VM received by the boost module 300 is a low-voltage power supply that is lower than the regulated operating voltage of the first clamp module 100, the first clamp module 100 is deemed to be an open circuit. At this time, the boost module 300 triples the power supply voltage VM. For the ground terminal, the boost voltage output by the boost module 300 is three times the power supply voltage VM.

[0046] like Figure 2 As shown, Figure 2 The circuit schematic diagram of the boost module provided by the embodiment of the utility model; the boost module 300 includes an RC oscillator circuit 301, a frequency division unit 302 and a charge pump boost unit 303; the first input end of the charge pump boost unit 303 is connected to the power supply voltage VM; the output end of the RC oscillator circuit 301 is connected to the input end of the frequency division unit 302; the second input end of the charge pump boost unit 303 is connected to the output end of the frequency division unit 302;

[0047] It should be noted that the RC oscillator circuit 301 is used to generate a pulse signal and send it to the frequency division unit 302. The frequency division unit 302 divides the received pulse signal and generates a square wave signal of a specific frequency. The charge pump boost unit 303 uses the square wave signal output by the frequency division unit 302 to alternately boost the power supply voltage VM and outputs the boosted voltage.

[0048] like Figure 5 As shown, Figure 5A structural schematic diagram of a signal generating module provided for an embodiment of the utility model; the signal generating module 700 includes an oscillator 701 and a signal processing module 702, wherein a first input terminal of the signal processing module 702 is connected to the oscillator 701, a second input terminal of the signal processing module 702 is used to receive an external level signal, and an output terminal of the signal processing module 702 is connected to a third input terminal of the driving module 500, for performing logic operation processing on the external level signal, generating a corresponding logic output signal and transmitting it to the driving module 500.

[0049] See also Figure 1 The electronically controlled switch group includes a first MOS tube M1 and a second MOS tube M2; the drain of the first MOS tube M1 is connected to the power supply voltage VM, the gate of the first MOS tube M1 is connected to the first output end of the driving module, and the gate of the second MOS tube M2 is connected to the second output end of the driving module; the source of the first MOS tube M1 is connected to the drain of the second MOS tube M2, and they serve as the output end of the electronically controlled switch group together, and the source of the second MOS tube M2 is grounded.

[0050] It should be further explained that the output end of the boost module 300 is connected to the input end of the LDO module 400, and the output end of the LDO module 400 is connected to the first input end of the driving module 500. The boost module 300 outputs the boosted voltage to the LDO module 400, and the LDO module 400 provides a low-voltage power supply and a current bias for the driving module 500; the output end of the boost module 300 is also connected to the second input end of the driving module 500, and provides a high-voltage power supply for the driving module 500; wherein the first MOS tube M1 is a high-side MOS tube, and the boost module 300 provides a high-voltage power supply to the driving module 500 to control the opening and closing of the first MOS tube M1; the second MOS tube M2 is a low-side MOS tube, and the boosted voltage output by the boost module 300 is stepped down by the LDO module 400, and the LDO module 400 provides a low-voltage power supply to the driving module, so that the driving module can control the working state of the low-side second MOS tube M2.

[0051] See also Figure 2 , the charge pump boost unit 303 includes a first diode D1, a second diode D2, a third diode D3, a fourth diode D4, a fifth diode D5, a sixth diode D6, a seventh diode D7, an eighth diode D8, a first inverter U1, a second inverter U2, a third inverter U3, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a third voltage regulator Q3 and a fourth voltage regulator Q4; wherein the first inverter U1, the second inverter U2 and the third inverter U3 all include an input terminal, an output terminal, a power supply terminal and a reference ground terminal, the power supply terminals of the first inverter U1, the second inverter U2 and the third inverter U3 are all connected to the power supply voltage VM, and the reference ground terminals are all floating (Floating GND);

[0052] The anode of the first diode D1 is connected to the anode of the second diode D2, and they are connected to the power supply voltage VM as the first input terminal of the charge pump boost unit 303. The cathode of the first diode D1 is connected to the anode of the third diode D3 and one end of the first capacitor C1; the cathode of the second diode D2 is connected to the anode of the fourth diode D4 and one end of the second capacitor C2; the cathode of the third diode D3 is connected to the cathode of the fourth diode D4, and is also connected to the anode of the fifth diode D5 and the anode of the sixth diode D6; the cathode of the fifth diode D5 is connected to the anode of the seventh diode D7 and one end of the third capacitor C3; the cathode of the sixth diode D6 is connected to the anode of the eighth diode D8 and one end of the fourth capacitor C4; the cathode of the seventh diode D7 is connected to the cathode of the eighth diode D8, and they are connected to the charge pump boost unit 303. The output end of the charge pump boost unit 303 outputs the boosted voltage after the boost; the input end of the first inverter U1 is connected to the input end of the second inverter U2, and together they serve as the second input end of the charge pump boost unit 303 connected to the output end of the frequency division unit 302; the output end of the first inverter U1 is connected to the other end of the first capacitor C1 and the other end of the third capacitor C3, the negative electrode of the third voltage regulator Q3 is connected to one end of the third capacitor C3, and the positive electrode of the third voltage regulator Q3 is connected to the other end of the third capacitor C3; the output end of the second inverter U2 is connected to the input end of the third inverter U3, the output end of the third inverter U3 is connected to the other end of the second capacitor C2 and the other end of the fourth capacitor C4, the negative electrode of the fourth voltage regulator Q4 is connected to one end of the fourth capacitor C4, and the positive electrode of the fourth voltage regulator Q4 is connected to the other end of the fourth capacitor C4.

[0053] As a further solution, the RC oscillator circuit 301 includes a second resistor R2, a third resistor R3, a fourth inverter U4 and a fifth capacitor C5; wherein the fourth inverter U4 includes an input end, an output end, a power supply end and a reference ground end; one end of the second resistor R2 and the input end of the fourth inverter U4 are connected to one end of the fifth capacitor C5, and the other end of the fifth capacitor C5 is grounded through the third resistor R3; the power supply end of the fourth inverter U4 is connected to the power supply voltage VM, the reference ground end of the fourth inverter U4 is floating, and the output end of the fourth inverter U4 is connected to the other end of the second resistor R2.

[0054] As a further solution, the frequency divider unit 302 is set by a frequency divider DFF, which includes a signal receiving end, a trigger end, an output end, a power supply end and a reference ground end; the signal receiving end of the frequency divider DFF is connected to the output end of the RC oscillation circuit 301, the power supply end of the frequency divider DFF is connected to the power supply voltage VM, the reference ground end of the frequency divider DFF is floating, and the output end of the frequency divider DFF is connected to the trigger end.

[0055] like Figure 4 As shown, Figure 4 A circuit structure diagram of a boost module and a clamp module in a low-voltage motor drive circuit is provided for an embodiment of the utility model.

[0056] In a specific embodiment, the input power supply voltage VM is a high voltage power supply higher than the voltage regulation working voltage of the first clamping module 100. The first clamping module 100 clamps the power supply voltage VM to the first clamping voltage. At this time, since the positive electrode of the first voltage regulator Q1 is floating, the potential difference between the clamped power supply voltage VM and the floating ground is 3V to 4V. The voltage difference between the power supply voltage VM and the floating ground will cause the RC oscillator circuit 301 and the cascade inverter to start working.

[0057] Among them, the RC oscillator circuit 301 generates a pulse signal to the D flip-flop of the frequency divider DFF, the D flip-flop has a frequency division function, and generates a square wave signal of a specific frequency to provide input for the subsequent inverter; the first inverter U1, the second inverter U2 and the third inverter U3 are cascaded in two stages, and the output voltage of the cascaded inverter changes periodically according to the square wave signal to produce alternating high and low levels. The diode and the capacitor form a boost circuit, and the cascaded inverter charges and discharges the capacitor through alternating half-cycle boosting in the upper and lower paths, forming a triple boost function to achieve a doubling effect on the power supply voltage.

[0058] like Figure 3 As shown, Figure 3 A circuit structure diagram of a first clamping module provided in an embodiment of the utility model; the first clamping module 100 includes a first voltage regulator Q1 and a first resistor R1, the cathode of the first voltage regulator Q1 is connected to the power supply voltage VM, and the anode of the first voltage regulator Q1 is grounded through the first resistor R1; wherein the end of the first resistor R1 away from the ground is a floating end.

[0059] In a specific embodiment, assuming that the voltage regulator working voltage of the first voltage regulator Q1 is 5V, when the power supply voltage VM is lower than the voltage regulator working voltage, the voltage regulator Q1 does not work, and the boost module 300 triples the power supply voltage VM. At this time, for the ground terminal: OUTPUT = 3*VM;

[0060] When the power supply voltage VM is higher than the regulated working voltage of the first voltage regulator Q1, the first voltage regulator Q1 clamps the power supply voltage VM, and the boost module 300 boosts the power supply voltage VM. The boosted voltage is clamped to the regulated working voltage 5V by the second voltage regulator Q2. At this time, for the ground terminal: OUTPUT = VM + 5V;

[0061] In summary, the present application can perform triple boost at a low power supply voltage. When the input power supply voltage VM is a high voltage, the clamping module is triggered to clamp the power supply voltage to stabilize the output voltage to prevent the output voltage from being too high and damaging the circuit.

[0062] In the specific implementation process, selective setting of different power supply ranges is achieved by selecting different voltage regulator tubes. Therefore, the technical solution of the present application can adapt to a wide range of power supply, which can not only ensure that the voltage can be effectively boosted and stabilized under different input voltages, but also ensure the required functions under the premise of stable circuit operation.

[0063] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model rather than to limit it. Although the utility model has been described in detail with reference to the preferred embodiments, ordinary technicians in the field should understand that the technical solution of the utility model can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the utility model, which should be included in the scope of the claims of the utility model.

Claims

1. A low voltage motor drive circuit, characterized in that: include: A first clamping module, a second clamping module, a boost module, an LDO module, a driving module, an electric control switch group and a signal generating module; The input end of the boost module and the input end of the second clamp module are grounded through the first clamp module and are connected to the power supply voltage VM, and the feedback end of the second clamp module is connected to the output end of the boost module; The output end of the boost module is connected to the input end of the LDO module and the first input end of the driving module, and the output end of the LDO module is connected to the second input end of the driving module; The output end of the signal generating module is connected to the driving control end of the driving module, and the output end of the driving module is connected to the input end of the electric control switch group.

2. A low voltage motor drive circuit according to claim 1, characterized in that: The boost module includes an RC oscillator circuit, a frequency division unit and a charge pump boost unit; The output end of the RC oscillator circuit is connected to the input end of the frequency division unit; The output end of the frequency dividing unit is connected to the second input end of the charge pump boost unit; The first input terminal of the charge pump boost unit is connected to the power supply voltage VM.

3. A low voltage motor drive circuit according to claim 1, characterized in that: The first clamping module includes a first voltage regulator tube and a first resistor. The cathode of the first voltage regulator tube is connected to the power supply voltage VM, and the anode of the first voltage regulator tube is grounded through the first resistor.

4. A low voltage motor drive circuit according to claim 1, characterized in that: The second clamping module includes a second voltage regulator tube, the positive electrode of the second voltage regulator tube is connected to the input end of the boost module, and the negative electrode of the second voltage regulator tube is connected to the output end of the boost module.

5. A low voltage motor drive circuit according to claim 2, characterized in that: The charge pump boost unit includes a first diode, a second diode, a third diode, a fourth diode, a fifth diode, a sixth diode, a seventh diode, an eighth diode, a first inverter, a second inverter, a third inverter, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a third voltage regulator and a fourth voltage regulator; wherein the first inverter, the second inverter and the third inverter each include an input terminal, an output terminal, a power supply terminal and a reference ground terminal, the power supply terminals of the first inverter, the second inverter and the third inverter are each connected to a power supply voltage VM, and the reference ground terminals are each floating; The anode of the first diode is connected to the anode of the second diode, and they are connected to the power supply voltage VM as the first input terminal of the charge pump boost unit, and the cathode of the first diode is connected to the anode of the third diode and one end of the first capacitor; The cathode of the second diode is connected to the anode of the fourth diode and one end of the second capacitor; the cathode of the third diode is connected to the cathode of the fourth diode and then to the anode of the fifth diode and the anode of the sixth diode; The cathode of the fifth diode is connected to the anode of the seventh diode and one end of the third capacitor; the cathode of the sixth diode is connected to the anode of the eighth diode and one end of the fourth capacitor; After the cathode of the seventh diode is connected to the cathode of the eighth diode, they serve together as the output end of the charge pump boost unit to output the boosted voltage; The input end of the first inverter is connected to the input end of the second inverter, and together they serve as the second input end of the charge pump boost unit and are connected to the output end of the frequency division unit; The output end of the first inverter is connected to the other end of the first capacitor and the other end of the third capacitor, the negative electrode of the third voltage regulator is connected to one end of the third capacitor, and the positive electrode of the third voltage regulator is connected to the other end of the third capacitor; The output end of the second inverter is connected to the input end of the third inverter, the output end of the third inverter is connected to the other end of the second capacitor and the other end of the fourth capacitor, the negative electrode of the fourth voltage regulator is connected to one end of the fourth capacitor, and the positive electrode of the fourth voltage regulator is connected to the other end of the fourth capacitor.

6. A low voltage motor drive circuit according to claim 2, characterized in that: The RC oscillator circuit includes a second resistor, a third resistor, a fourth inverter and a fifth capacitor; wherein the fourth inverter includes an input terminal, an output terminal, a power supply terminal and a reference ground terminal; One end of the second resistor and the input end of the fourth inverter are connected to one end of the fifth capacitor, and the other end of the fifth capacitor is grounded through the third resistor; the power supply end of the fourth inverter is connected to the power supply voltage VM, the reference ground end of the fourth inverter is floating, and the output end of the fourth inverter is connected to the other end of the second resistor.

7. A low voltage motor drive circuit according to claim 2, characterized in that: The frequency dividing unit is set by a frequency divider, and the frequency divider includes a signal receiving end, a trigger end, an output end, a power supply end and a reference ground end; the signal receiving end of the frequency divider is connected to the output end of the RC oscillation circuit, the power supply end of the frequency divider is connected to the power supply voltage VM, the reference ground end of the frequency divider is floating, and the output end of the frequency divider is connected to the trigger end.

8. The low voltage motor drive circuit according to claim 1, characterized in that: The signal generating module comprises an oscillator and a signal processing module, wherein a first input end of the signal processing module is connected to the oscillator, a second input end of the signal processing module is used to receive an external level signal, and an output end of the signal processing module is connected to a driving control end of the driving module.

9. The low voltage motor drive circuit according to claim 1, characterized in that: The electronically controlled switch group includes a first MOS tube and a second MOS tube; The drain of the first MOS transistor is connected to the power supply voltage VM, the gate of the first MOS transistor is connected to the first output terminal of the driving module, and the gate of the second MOS transistor is connected to the second output terminal of the driving module; The source of the first MOS tube is connected to the drain of the second MOS tube and serves together as an output end of the electric control switch group, and the source of the second MOS tube is grounded.

Images