A solenoid valve shut-off discharge circuit

Abstract

The present application discloses a solenoid valve shutoff discharge circuit, which relates to the field of circuit control technology. The circuit includes a drive module DRV, a solenoid valve coil L0 and a solenoid valve switch M0, and also includes a current mirror module, a unidirectional conduction module, a clamping module and a driving resistor module. The current mirror module is used to provide discharge conditions when the solenoid valve coil L0 generates a reverse electromotive force; the unidirectional conduction module is used to provide a turn-on voltage to the solenoid valve switch M0 when a reverse electromotive force is generated, so that it is turned on again and quickly discharges the reverse electromotive force; the clamping module is used to limit the control terminal voltage of the solenoid valve switch M0; the driving resistor module adjusts the voltage of node A according to the output signal of the drive module DRV to control the on and off of the solenoid valve switch M0. Through the cooperation of various modules, this solution effectively controls the energy release of the reverse electromotive force, prevents damage to circuit components caused by excessively high voltage, and optimizes the performance of the solenoid valve without adding additional complexity.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit control, and in particular to a solenoid valve shut-off discharge circuit. Background Art

[0002] Solenoid valves, which utilize electromagnetic force to control fluid flow, are widely used in industrial automation and civilian systems. They operate by driving a solenoid coil to control the flow of fluids. Due to their fast response, remote control, high reliability, and versatility, solenoid valves have become a core component in the fluid control field, playing a vital role in regulating the flow rate, direction, and pressure of liquids and gases.

[0003] In actual applications, when the solenoid valve is turned off, its coil will generate a reverse voltage, namely a reverse electromotive force, due to the electromagnetic induction effect. This reverse electromotive force may damage the drive circuit and related components. In the prior art, in order to suppress the influence of the reverse electromotive force, a reverse freewheeling diode is usually connected in parallel at both ends of the solenoid valve coil. The freewheeling diode releases the reverse electromotive force by providing a low-impedance path, thereby effectively protecting the safety of the circuit. However, this freewheeling protection method changes the original characteristics of the circuit, resulting in a certain delay in the operation of the solenoid valve, which has an adverse effect on the system performance. In addition, in high-frequency operation or high-current scenarios, the reverse electromotive force may also cause power supply voltage fluctuations through the power supply circuit, affecting the overall stability of the system.

[0004] Therefore, how to quickly release the reverse electromotive force of the solenoid valve while ensuring circuit safety and component protection, thereby reducing action delay and power supply fluctuations, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of the present invention is to provide a solenoid valve shut-off discharge circuit, which effectively controls the energy release of the reverse electromotive force by adaptively discharging at the moment the solenoid valve is shut off, and significantly improves the response speed under high frequency or high current conditions, thereby enhancing the stability and working efficiency of the system.

[0006] To achieve the above objectives, the present invention discloses the following technical solutions:

[0007] In one aspect, the present invention provides a solenoid valve shutoff discharge circuit, comprising a drive module DRV, a solenoid valve coil L0, and a solenoid valve switch M0, and further comprising:

[0008] A current mirror module, configured to provide a discharge condition when the solenoid valve coil L0 generates a reverse electromotive force, the current mirror module comprising a first current branch and a second current branch; one end of the first current branch is connected to one end of the solenoid valve coil L0 and is connected to a power supply voltage VCC, and the other end of the first current branch is grounded; one end of the second current branch is connected to the other end of the solenoid valve coil L0 via a node B, and the other end of the second current branch is connected to the positive terminal of the unidirectional conduction module;

[0009] a unidirectional conduction module, the negative terminal of which is connected to the control terminal of the solenoid valve switch M0. When the solenoid valve switch M0 is turned off and a reverse electromotive force is generated in the solenoid valve coil L0, the reverse electromotive force provides a turn-on voltage to the control terminal of the solenoid valve switch M0 through the second current branch and the unidirectional conduction module, so that the solenoid valve switch M0 is turned on again and the reverse electromotive force is quickly discharged;

[0010] a clamping module, one end of which is connected to a node A between the unidirectional conduction module and the control end of the solenoid valve switch M0, and the other end of which is grounded, for limiting the voltage generated by the reverse electromotive force at the control end of the solenoid valve switch M0;

[0011] The driving resistor module has one end connected to the node A and the other end connected to the output end of the driving module DRV, and is used to adjust the voltage of the node A according to the output signal of the driving module DRV to control the opening and closing of the solenoid valve switch M0.

[0012] Optionally, in the above-mentioned solenoid valve shutoff discharge circuit, when the input signal S_CTRL of the driving module DRV is at a high level, the driving module DRV outputs an on-drive signal, the driving resistor module pulls up the voltage of node A, turns on the solenoid valve switch M0, and reduces the voltage of node B; at this time, due to the limitation of the unidirectional conduction module, the current does not flow from node A to node B, the power supply voltage VCC charges the solenoid valve coil L0, and the charging current of the solenoid valve coil L0 gradually increases over time until the state of the solenoid valve changes and reaches a stable state;

[0013] When the input signal S_CTRL of the drive module DRV changes from a high level to a low level, the drive module DRV outputs a shutdown drive signal, and the drive resistor module pulls down the voltage of node A, turning off the solenoid valve switch M0; at this time, the reverse electromotive force generated by the solenoid valve coil L0 charges the parasitic capacitance of the solenoid valve switch M0, causing the voltage of node B to increase, the second current branch begins to conduct and the voltage of node A gradually increases. When the voltage of node A increases to the point where the solenoid valve switch M0 is turned on again, the reverse electromotive force generated by the solenoid valve coil L0 is quickly discharged through the solenoid valve switch M0 until the solenoid valve returns to its initial state.

[0014] Optionally, in the above-mentioned solenoid valve shutdown discharge circuit, the first current branch includes a first switch tube M1 and a constant current source I0, and the second current branch includes a second switch tube M2; the power supply voltage VCC is grounded via the first switch tube M1 and the constant current source I0 in sequence; the control end of the first switch tube M1 is connected to the control end of the second switch tube M2 and is connected to the input end of the constant current source I0, so as to provide a bias voltage for the second switch tube M2 through the constant current source I0.

[0015] Optionally, in the above-mentioned solenoid valve shutdown discharge circuit, the first switch tube M1 and the second switch tube M2 are both PMOS tubes, the source of the first switch tube M1 is connected to one end of the solenoid valve coil L0, and the drain is connected to the constant current source I0; the source of the second switch tube M2 is connected to the other end of the solenoid valve coil L0, and the drain is connected to one end of the unidirectional conduction module.

[0016] Optionally, in the above-mentioned solenoid valve shut-off discharge circuit, the one-way conduction module includes a rectifier diode D1 , an anode of the rectifier diode D1 is connected to the drain of the second switch tube M2 , and a cathode is connected to the control end of the solenoid valve switch M0 .

[0017] Optionally, in the above-mentioned solenoid valve shut-off discharge circuit, the clamping module includes a Zener diode D0, the cathode of the Zener diode D0 is connected to node A, and the anode is grounded, for limiting the voltage generated at node A by the reverse electromotive force of the solenoid valve coil L0.

[0018] Optionally, in the above-mentioned solenoid valve shutdown discharge circuit, the driving resistor module includes an initialization resistor R0 and a bias resistor R1; wherein, one end of the initialization resistor R0 is grounded, and the other end is connected to one end of the bias resistor R1 and connected to the output end of the driving module DRV, for ensuring that the control end voltage of the solenoid valve switch M0 is always at a low level before the circuit is started; the other end of the bias resistor R1 is connected to the control end of the solenoid valve switch M0, for transmitting the control end voltage of the solenoid valve switch M0, and providing a bias voltage for the control end of the solenoid valve switch M0 when discharging the reverse electromotive force.

[0019] Optionally, the solenoid valve turns off the discharge circuit, and the current value of the constant current source I0 is set to:

[0020] ;

[0021] Where I0 is the current value of the constant current source, N1 / N2 is the ratio of the width to length of the second switch tube M2 to the first switch tube M1, R1 is the resistance of the bias resistor, V TH_M0 is the conduction threshold voltage of the solenoid valve switch M0.

[0022] Optionally, in the above-mentioned solenoid valve shutoff discharge circuit, when the input signal S_CTRL of the driving module DRV is at a continuous low level, the back electromotive force is discharged, the driving module DRV outputs a shutoff drive signal, and after passing through the driving resistor module, the voltage of the node A is pulled down, and the solenoid valve switch M0 is turned off; at this time, the voltage of the node B is equal to the power supply voltage VCC, and the current IL in the solenoid valve coil L0 is 0A;

[0023] When the input signal S_CTRL of the driving module DRV is at a high level, the driving module DRV outputs a turn-on driving signal, which causes the voltage at node A to rise to a high level after passing through the bias resistor R1. The solenoid valve switch M0 is turned on, and the voltage at node B is pulled down. At this time, due to the limitation of the unidirectional conduction module, current does not flow from node A to node B. The current IL in the solenoid valve coil L0 gradually increases over time until the current reaches a steady state.

[0024] At the moment when the input signal S_CTRL of the drive module DRV changes from a high level to a low level, the drive module DRV outputs a shutdown drive signal, and the voltage of node A drops rapidly, causing the solenoid valve switch M0 to be turned off; at this time, the reverse electromotive force generated by the solenoid valve coil L0 charges the parasitic capacitance of the solenoid valve switch M0, causing the voltage of node B to increase, the second current branch begins to conduct and the voltage of node A gradually increases. When the voltage of node A increases to the point where the solenoid valve switch M0 is turned on again, the reverse electromotive force generated by the solenoid valve coil L0 is quickly discharged through the solenoid valve switch M0 until the energy is completely discharged, the solenoid valve returns to its initial state, and the voltage of node B returns to the power supply voltage VCC again.

[0025] Another aspect of the present invention provides a solenoid valve control system, comprising the solenoid valve shutoff discharge circuit as described in the first aspect.

[0026] The effects provided in the summary of the invention are only the effects of the embodiments, not all the effects of the invention. One of the above technical solutions has the following advantages or beneficial effects:

[0027] The present application provides a solenoid valve shut-off discharge circuit, which realizes adaptive discharge at the moment of solenoid valve shut-off by cooperating existing components with a current mirror module, a unidirectional conduction module, a clamping module, and a driving resistor module, and significantly improves the response speed and stability, especially under high-frequency or high-current working conditions. This solution provides the discharge conditions of the reverse electromotive force through the current mirror module; the unidirectional conduction module provides a turn-on voltage for the solenoid valve switch M0 when generating the reverse electromotive force; the clamping module limits the voltage generated by the reverse electromotive force at the control end of the solenoid valve switch M0; and the driving resistor module adjusts the control end voltage of the solenoid valve switch M0 according to the output signal of the driving module DRV. This solution effectively controls the energy release of the reverse electromotive force through the synergistic effect of various device modules, prevents damage to circuit components caused by excessive voltage, and ensures that the solenoid valve shut-off process is fast and stable, optimizing the performance of the solenoid valve without adding additional complexity. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0029] Figure 1 This is a schematic diagram of a solenoid valve discharge circuit in the prior art;

[0030] Figure 2 This is a schematic diagram of the structure of a solenoid valve shut-off discharge circuit according to an embodiment of the present application;

[0031] Figure 3 This is a schematic diagram of a solenoid valve shut-off discharge circuit according to an embodiment of the present application;

[0032] Figure 4 for Figure 3 A signal waveform diagram of the solenoid valve shutting off the discharge circuit. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0034] It should be noted that references to "one embodiment," "an embodiment," "an example embodiment," etc., in this specification indicate that the described embodiment may include specific features, structures, or characteristics. However, not every embodiment must include these specific features, structures, or characteristics. In addition, such references do not necessarily refer to the same embodiment. Furthermore, when specific features, structures, or characteristics are described in conjunction with an embodiment, whether or not explicitly described, it is indicated that it is within the knowledge of those skilled in the art to incorporate such features, structures, or characteristics into other embodiments.

[0035] Figure 1 This is a schematic diagram of a solenoid valve discharge circuit in the prior art. Figure 1 As shown in the figure, the discharge circuit includes the solenoid valve coil L0, a reverse freewheeling diode D0, a solenoid valve switch control transistor M0, a driver module DRV, and a bias resistor R0. When the control signal S_CTRL is high (S_CTRL = 1), the driver module DRV outputs an on-drive signal, turning on the switch control transistor M0. At this point, current flows through the solenoid valve coil L0, actuating the valve core and changing the state of the solenoid valve. When the control signal S_CTRL is low (S_CTRL = 0), the driver module DRV outputs an off-drive signal, turning off the switch control transistor M0. At this point, the reverse electromotive force generated by the solenoid valve coil L0 is dissipated through the freewheeling diode D0, the coil's magnetic field disappears, and the solenoid valve core returns to its initial state.

[0036] Although Figure 1 The solenoid valve discharge circuit in the present invention effectively protects the circuit from damage caused by reverse electromotive force through measures such as the reverse freewheeling diode D0. However, this protection method has a certain impact on the operation speed of the solenoid valve and the stability of the power supply system. To address this problem, the present invention provides a solenoid valve shutdown discharge circuit that can adaptively discharge at the moment the solenoid valve is shut off, significantly improving the response speed, especially under high-frequency or high-current conditions, and enhancing the stability and operating efficiency of the system.

[0037] refer to Figure 2 , Figure 2A schematic diagram of the structure of a solenoid valve shut-off discharge circuit according to an embodiment of the present application is shown. The circuit includes a drive module DRV, a solenoid valve coil L0, and a solenoid valve switch M0 in the prior art. In addition, it also includes a current mirror module 110, a unidirectional conduction module 120, a clamping module 130, and a driving resistor module 140. The current mirror module 110 includes a first current branch and a second current branch, which are used to generate a reverse electromotive force in the solenoid valve coil L0 to provide discharge conditions. The input end of the first current branch is connected to one end of the solenoid valve coil L0 and is connected to the power supply voltage VCC, and the other end is grounded; the input end of the second current branch is connected to the other end of the solenoid valve coil L0 through a node B, and the output end is connected to the positive end of the unidirectional conduction module 120. The negative terminal of the unidirectional conduction module 120 is connected to the control terminal of the solenoid valve switch M0. When the solenoid valve switch M0 is turned off and a reverse electromotive force is generated in the solenoid valve coil L0, the reverse electromotive force flows through the second current branch and the unidirectional conduction module to provide a turn-on voltage to the control terminal of the solenoid valve switch M0, causing the solenoid valve switch M0 to turn on again and quickly discharge the reverse electromotive force. The clamping module 130 has one terminal connected to node A between the unidirectional conduction module 120 and the control terminal of the solenoid valve switch M0, and the other terminal is grounded. This clamping module is used to limit the voltage generated by the reverse electromotive force at the control terminal of the solenoid valve switch M0. The driving resistor module 140 has one terminal connected to node A and the other terminal connected to the output terminal of the driving module DRV. It is used to adjust the voltage at node A based on the output signal of the driving module DRV to control the on and off of the solenoid valve switch M0.

[0038] In this circuit, when the input signal S_CTRL to the driver module DRV is high, the driver module DRV outputs an on-drive signal, which drives the resistor module 140 to raise the voltage at node A, turning on the solenoid valve switch M0. At this point, due to the limitations of the unidirectional conduction module 120, current does not flow from node A to node B. The charging current in the solenoid valve coil L0 gradually increases over time until the solenoid valve state changes and reaches a stable state. When the input signal S_CTRL to the driver module DRV is low, the driver module DRV outputs an off-drive signal, which drives the resistor module 140 to lower the voltage at node A, turning off the solenoid valve switch M0. At this point, solenoid valve coil L0 generates a reverse electromotive force (EMF), driving current to charge the parasitic capacitance Cds of solenoid valve switch M0, raising the voltage at node B. As the voltage at node B increases, the second current branch becomes conductive, gradually increasing the voltage at node A. When the voltage at node A rises to a level that turns on solenoid valve switch M0 again, the reverse electromotive force generated by solenoid valve coil L0 is discharged through solenoid valve switch M0. During this process, clamping module 130 limits the voltage at node A to prevent damage to circuit components caused by excessive voltage until the energy in solenoid valve coil L0 is fully released, the solenoid valve returns to its initial state, and the circuit enters a static state.

[0039] The circuit structure of this embodiment achieves adaptive discharge at the moment the solenoid valve shuts off, significantly improving response speed and enhancing system stability and efficiency, particularly under high-frequency or high-current operating conditions. Through the synergistic effect of various device modules, this circuit effectively controls the release of back electromotive force energy, preventing damage to circuit components caused by excessive voltage. It also ensures a fast and stable shutoff process for the solenoid valve, optimizing its performance without adding additional complexity.

[0040] refer to Figure 3 , Figure 3 The schematic diagram of a solenoid valve shutoff discharge circuit according to an embodiment of the present application is shown. In this embodiment, the first current branch of the current mirror module 110 includes a first switch tube M1 and a constant current source I0, and the second current branch includes a second switch tube M2. The power supply voltage VCC is connected to the ground through the first switch tube M1 and the constant current source I0 in sequence; the control end of the first switch tube M1 is connected to the control end of the second switch tube M2 and is connected to the input end of the constant current source I0 to provide a bias voltage through the constant current source I0 to control the conduction state of the second switch tube M2. Preferably, the first switch tube M1 and the second switch tube M2 are both PMOS tubes. Specifically, the source of the first switch tube M1 is connected to one end of the solenoid valve coil L0, and the drain is connected to the constant current source I0; the source of the second switch tube M2 is connected to the other end of the solenoid valve coil L0, and the drain is connected to one end of the unidirectional conduction module 120.

[0041] In some embodiments, the unidirectional conduction module 120 includes a rectifier diode D1. The anode of the rectifier diode D1 is connected to the drain of the second switch M2, and the cathode is connected to the control terminal of the solenoid valve switch M0. The rectifier diode D1 limits the charging path from node A to node B. When the solenoid valve switch M0 is turned off, it directs the reverse electromotive force current generated by the solenoid valve coil L0 to the control terminal of the solenoid valve switch M0, thereby increasing the voltage level at node A and re-opening the solenoid valve switch M0.

[0042] In some embodiments, the clamping module 130 includes a Zener diode D0, with its cathode connected to node A and its anode grounded. When the second current branch is conducting, Zener diode D0 limits the voltage generated by the reverse electromotive force at node A, effectively protecting the circuit from overvoltage and ensuring voltage stability during the solenoid valve shutdown process. In other embodiments, the clamping module 130 can also be another circuit with voltage stabilization capabilities, without limitation.

[0043] In some embodiments, the drive resistor module 140 includes an initialization resistor R0 and a bias resistor R1. Initialization resistor R0 has one end connected to ground, and the other end connected to one end of bias resistor R1 and to the output of driver module DRV. This ensures that the control terminal voltage of solenoid valve switch M0 remains low before the circuit is activated. The other end of bias resistor R1 is connected to the control terminal of solenoid valve switch M0, transmitting the control terminal voltage of solenoid valve switch M0 and providing a bias voltage for the control terminal of solenoid valve switch M0 during back electromotive force (BEM) discharge.

[0044] In some embodiments, preferably, the current value of the constant current source I0 is set to:

[0045] ;

[0046] Where I0 is the current value of the constant current source, N1 / N2 is the ratio of the width to length of the second switch tube M2 to the first switch tube M1, R1 is the resistance of the bias resistor, V TH_M0 is the conduction threshold voltage of the electromagnetic valve switch M0. Wherein, under the condition of satisfying formula (1), the ratio of the width to length ratio of the second switch tube M2 to the first switch tube M1 can be freely set according to actual needs.

[0047] Figure 4 for Figure 3 A signal waveform diagram of the solenoid valve shut-off discharge circuit. Figure 3 and Figure 4 It can be seen that the working process of the circuit is as follows:

[0048] During the period 0 to t1, the input signal S_CTRL to the driver module DRV remains at a continuous low level (S_CTRL = 0). The back electromotive force is completely discharged, and the driver module DRV outputs a shutdown drive signal. After passing through bias resistor R1, the voltage at node A is at a low level, turning off the solenoid valve switch M0. After the solenoid valve switch M0 is turned off, the charging path for the solenoid valve coil L0 is cut off, and the power supply voltage VCC no longer charges the solenoid valve coil L0. At this point, the voltage at node B equals the power supply voltage VCC, and the current IL in the solenoid valve coil L0 is 0A.

[0049] During the period t1 to t2, the input signal S_CTRL of the driver module DRV is high, and the driver module DRV outputs the on-drive signal. After passing through the bias resistor R1, the voltage at node A is high, turning on the solenoid valve switch M0. This pulls down the voltage at node B, and the power supply voltage VCC charges the solenoid valve coil L0. According to the current formula I = U × T / L, where I is current, U is voltage, and T is time, the current IL in the solenoid valve coil L0 can be expressed as IL = VCC × t / L, where t is the on-time of the solenoid valve switch M0 and L is the inductance of the solenoid valve coil L0. Therefore, the current IL in the solenoid valve coil L0 increases proportionally with the on-time of the solenoid valve switch M0. When the on-time of the solenoid valve switch M0 exceeds the saturation time of the solenoid valve coil L0, the current IL reaches a stable state and no longer increases.

[0050] During the period t2-t3, at the moment the input signal S_CTRL of the driver module DRV transitions from a high level to a low level, the driver module DTV outputs a shutdown drive signal, causing the voltage at node A to drop rapidly, shutting off the solenoid valve switch M0. During this process, the sudden change in current in the solenoid valve coil L0 generates a reverse electromotive force (EMF). This reverse electromotive force charges the parasitic capacitance Cds of M0, causing the voltage at node B to rise. The second switch M2 then turns on, and the unidirectional conduction module 120 gradually increases the voltage at node A. The unidirectional conduction module 120 can be used to guide current and limit its flow. When the voltage at node A rises to a level that turns the solenoid valve switch M0 back on, the reverse electromotive force generated by the solenoid valve coil L0 is rapidly discharged through the solenoid valve switch M0 until the energy is completely discharged and the solenoid valve returns to its initial state. At this point, the voltage at node B returns to the power supply voltage VCC, and the solenoid valve completes a complete switching cycle.

[0051] In practical applications, the circuit structure of this embodiment is also applicable to circuits such as relays that have coil inductance that needs to be discharged quickly.

[0052] From the above analysis, it can be seen that the solenoid valve shutdown discharge circuit of the embodiment of the present application realizes efficient energy release at the moment of solenoid valve shutdown by integrating the current mirror module, the unidirectional conduction module, the clamping module and the drive resistor module. Compared with the traditional design, this circuit omits the traditional freewheeling diode, and the structure is simpler. At the same time, it can adaptively discharge without the need for additional control circuits, effectively reducing the design complexity and cost. Under high frequency or high current conditions, this circuit has a fast response capability, and by multiplexing the switching solenoid valve switch M0, it not only improves the energy discharge efficiency, but also effectively protects the circuit components from the high-voltage impact of the reverse electromotive force. In addition, in the equilibrium state, the setting of the current mirror module does not interfere with the normal operation of the solenoid valve switch M0, ensuring the stability of the system.

[0053] It should be noted that the solenoid valve shutoff discharge circuit in the above embodiment is only a preferred circuit structure for achieving the purpose of the present invention. In other embodiments, each circuit module or device may also use other circuit structures that can achieve the same function, and the present application is not limited thereto.

[0054] In addition, embodiments of the present application also provide a solenoid valve control system, including the solenoid valve shutoff discharge circuit described in the aforementioned embodiments, for achieving rapid, safe, and adaptive release of the solenoid valve's reverse electromotive force. For details regarding the circuit structure and operating process of the solenoid valve control system not described in detail in this embodiment, please refer to the relevant sections of the aforementioned solenoid valve shutoff discharge circuit embodiment and will not be further elaborated here.

[0055] The above description is merely a preferred embodiment of the present invention and does not constitute any other form of limitation to the present invention. Any person skilled in the art may utilize the technical contents disclosed above to change or modify them into equivalent embodiments with equivalent changes for application in other fields. However, any simple modification, equivalent change, and modification of the above embodiments made in accordance with the technical essence of the present invention without departing from the technical solution of the present invention shall still fall within the scope of protection of the technical solution of the present invention.

Claims

1. A solenoid valve shut-off discharge circuit, comprising a drive module DRV, a solenoid valve coil L0 and a solenoid valve switch M0, characterized in that: Also includes: a current mirror module, configured to provide a discharge condition when the solenoid valve coil L0 generates a reverse electromotive force, the current mirror module comprising a first current branch and a second current branch; One end of the first current branch is connected to one end of the solenoid valve coil L0 and is connected to the power supply voltage VCC, and the other end of the first current branch is grounded; one end of the second current branch is connected to the other end of the solenoid valve coil L0 via node B, and the other end of the second current branch is connected to the positive terminal of the unidirectional conduction module; a unidirectional conduction module, the negative terminal of which is connected to the control terminal of the solenoid valve switch M0. When the solenoid valve switch M0 is turned off and a reverse electromotive force is generated in the solenoid valve coil L0, the reverse electromotive force provides a turn-on voltage to the control terminal of the solenoid valve switch M0 through the second current branch and the unidirectional conduction module, so that the solenoid valve switch M0 is turned on again and the reverse electromotive force is quickly discharged; a clamping module, one end of which is connected to a node A between the unidirectional conduction module and the control end of the solenoid valve switch M0, and the other end of which is grounded, for limiting the voltage generated by the reverse electromotive force at the control end of the solenoid valve switch M0; A driving resistor module, one end of which is connected to the node A and the other end is connected to the output end of the driving module DRV, and is used to adjust the voltage of the node A according to the output signal of the driving module DRV to control the opening and closing of the solenoid valve switch M0; When the input signal S_CTRL of the driving module DRV is at a high level, the driving module DRV outputs a turn-on driving signal, the driving resistor module pulls up the voltage of node A, turns on the solenoid valve switch M0, and reduces the voltage of node B. At this time, due to the limitation of the unidirectional conduction module, the current does not flow from node A to node B, and the power supply voltage VCC charges the solenoid valve coil L0. The charging current of the solenoid valve coil L0 gradually increases over time until the state of the solenoid valve changes and reaches a stable state.

2. The solenoid valve shutoff discharge circuit according to claim 1, characterized in that: When the input signal S_CTRL of the drive module DRV changes from a high level to a low level, the drive module DRV outputs a shutdown drive signal, and the drive resistor module pulls down the voltage of node A, turning off the solenoid valve switch M0; at this time, the reverse electromotive force generated by the solenoid valve coil L0 charges the parasitic capacitance of the solenoid valve switch M0, causing the voltage of node B to increase, the second current branch begins to conduct and the voltage of node A gradually increases. When the voltage of node A increases to the point where the solenoid valve switch M0 is turned on again, the reverse electromotive force generated by the solenoid valve coil L0 is quickly discharged through the solenoid valve switch M0 until the solenoid valve returns to its initial state.

3. The solenoid valve shutoff discharge circuit according to claim 1, characterized in that: The first current branch includes a first switch tube M1 and a constant current source I0, and the second current branch includes a second switch tube M2. The power supply voltage VCC is connected to ground via the first switch tube M1 and the constant current source I0 in sequence. The control end of the first switch tube M1 is connected to the control end of the second switch tube M2 and is also connected to the input end of the constant current source I0, so that a bias voltage for the second switch tube M2 is provided via the constant current source I0.

4. The solenoid valve shutoff discharge circuit according to claim 3, characterized in that: The first switch tube M1 and the second switch tube M2 are both PMOS tubes. The source of the first switch tube M1 is connected to one end of the solenoid valve coil L0, and the drain is connected to the constant current source I0; the source of the second switch tube M2 is connected to the other end of the solenoid valve coil L0, and the drain is connected to one end of the unidirectional conduction module.

5. The solenoid valve shutoff discharge circuit according to claim 4, characterized in that: The one-way conduction module includes a rectifier diode D1 , an anode of the rectifier diode D1 is connected to the drain of the second switch tube M2 , and a cathode of the rectifier diode D1 is connected to the control end of the solenoid valve switch M0 .

6. The solenoid valve shutoff discharge circuit according to claim 5, characterized in that: The clamping module includes a voltage-stabilizing diode D0 , wherein the cathode of the voltage-stabilizing diode D0 is connected to the node A and the anode is grounded, and is used to limit the voltage generated at the node A by the reverse electromotive force of the solenoid valve coil L0 .

7. The solenoid valve shutoff discharge circuit according to claim 6, characterized in that: The driving resistor module includes an initialization resistor R0 and a bias resistor R1; wherein, one end of the initialization resistor R0 is grounded, and the other end is connected to one end of the bias resistor R1 and connected to the output end of the driving module DRV, which is used to keep the control end voltage of the solenoid valve switch M0 at a low level before the circuit is started; the other end of the bias resistor R1 is connected to the control end of the solenoid valve switch M0, which is used to transmit the control end voltage of the solenoid valve switch M0 and provide a bias voltage for the control end of the solenoid valve switch M0 when discharging the reverse electromotive force.

8. The solenoid valve shutoff discharge circuit according to claim 7, characterized in that: The constant current source The current value is set to: Where, is the current value of the constant current source, N1 / N2 is the ratio of the width to length of the second switch tube M2 to the first switch tube M1, R1 is the resistance of the bias resistor, V TH_M0 is the conduction threshold voltage of the solenoid valve switch M0.

9. The solenoid valve shutoff discharge circuit according to any one of claims 3 to 8, characterized in that: When the input signal S_CTRL of the driving module DRV is at a continuous low level, the back electromotive force is discharged, and the driving module DRV outputs a shutdown driving signal, which pulls down the voltage of the node A after passing through the driving resistor module, and the solenoid valve switch M0 is turned off; At this time, the voltage of the node B is equal to the power supply voltage VCC, and the current IL in the solenoid valve coil L0 is 0A; When the input signal S_CTRL of the driver module DRV is high, the driver module DRV outputs a turn-on drive signal. After passing through the bias resistor R1, the voltage at node A is high, the solenoid valve switch M0 is turned on, and the voltage at node B is pulled low. At this time, due to the limitation of the unidirectional conduction module, current does not flow from node A to node B. The power supply voltage VCC charges the solenoid valve coil L0, and the current IL in the solenoid valve coil L0 gradually increases over time until the current reaches a steady state. At the moment when the input signal S_CTRL of the drive module DRV changes from a high level to a low level, the drive module DRV outputs a shutdown drive signal, and the voltage of node A drops rapidly, causing the solenoid valve switch M0 to be turned off; at this time, the reverse electromotive force generated by the solenoid valve coil L0 charges the parasitic capacitance of the solenoid valve switch M0, causing the voltage of node B to increase, the second current branch begins to conduct and the voltage of node A gradually increases. When the voltage of node A increases to the point where the solenoid valve switch M0 is turned on again, the reverse electromotive force generated by the solenoid valve coil L0 is quickly discharged through the solenoid valve switch M0 until the energy is completely discharged, the solenoid valve returns to its initial state, and the voltage of node B returns to the power supply voltage VCC again.

10. A solenoid valve control system, characterized in that: The invention comprises the solenoid valve shut-off discharge circuit according to any one of claims 1 to 9.

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