Electromagnetic valve driving circuit with all-in-one overcurrent protection function

Abstract

The utility model relates to solenoid valve drive circuit technical field, concretely relates to a solenoid valve drive circuit with many all -in -one overcurrent protection function, including several groups'solenoid valve drive circuit, several groups's voltage acquisition circuit, current sampling circuit and overcurrent protection circuit, several groups'solenoid valve drive circuit and several groups's voltage acquisition circuit corresponding connection, and solenoid valve drive circuit includes input comparator, MOS tube and solenoid valve that connect in proper order, and the both ends of current sampling circuit are connected with solenoid valve drive circuit and overcurrent protection circuit including feedback comparator, and the output of feedback comparator is connected with the input of input comparator, and input comparator controls the intercommunication state of MOS tube according to the circuit signal of feedback comparator output, thereby controls the operating state of solenoid valve, the utility model passes through modularization architecture multipath sharing protection circuit, and the element configuration of driving level is simplified, realizes the intensification of circuit design and functional integration while improving reliability.

Description

Technical Field

[0001] This utility model relates to the field of electromagnetic valve drive circuit technology, specifically to an electromagnetic valve drive circuit with multi-function overcurrent protection. Background Technology

[0002] Solenoid valves are industrial devices that use electromagnetic control to switch. They are basic components of automation used to control fluids and belong to the actuator category. They are widely used in various commercial and industrial technology fields such as industrial sewing, rail transportation, automotive electronics, medical electronics, and intelligent control, as well as in household appliances.

[0003] Currently, many solenoid valve drive circuits use pulse width modulation (PWM) circuits, employing metal-oxide-semiconductor (MOSFET) transistors as switching devices to control the solenoid valve. However, if the MOSFET breaks down and short-circuits, this type of drive circuit can easily cause overcurrent in the solenoid valve, leading to its burnout. Commonly used overcurrent protection circuits are relatively simple, generally only providing short-circuit protection for MOSFET breakdown. They rely on a processor to detect persistently high current in the circuit, resulting in a slow response. By the time the processor detects the overcurrent and reacts, the device may already be damaged. Furthermore, if the processor itself malfunctions, it may fail to detect excessive current, potentially exacerbating the problem. For some specialized applications, such as combination cylinder valves in hydrogen storage devices, where safety requirements are extremely high, existing general overcurrent protection circuits cannot provide tiered overcurrent protection, meaning they cannot protect against overcurrent even when the drive current decreases.

[0004] Traditional solenoid valve drive circuits, such as half-bridge or full-bridge drives, consist of a driver chip, MOSFETs, and numerous resistors and capacitors, making them complex to design and difficult to debug. Furthermore, each drive circuit requires at least one driver chip and one MOSFET. In applications with multiple solenoid valves to be driven, this results in a complex MOSFET array, significantly increasing cost and space requirements. Simultaneously, using low-cost MOSFETs leads to low drive voltage, high on-resistance, and high heat generation, necessitating sacrifices in power consumption, heat dissipation, and size; conversely, using MOSFETs with low on-resistance results in higher costs.

[0005] With the continuous improvement of industrial automation and the increasing demands for safety and reliability from various equipment, a more sophisticated solenoid valve drive circuit is needed. This circuit must not only effectively drive the solenoid valve but also possess reliable overcurrent protection to prevent equipment damage and safety accidents caused by overcurrent. Simultaneously, while meeting performance requirements, the circuit's complexity and cost should be minimized, while improving its stability and applicability. Therefore, researching a solenoid valve drive circuit with multi-functional overcurrent protection has significant practical importance and application value. Utility Model Content

[0006] To address the existing technical problems, this utility model provides a solenoid valve drive circuit with multi-functional overcurrent protection. This solenoid valve drive circuit constructs a multi-functional protection system at the system architecture level. Through the coordinated linkage of the solenoid valve drive circuit, voltage acquisition, current sampling, and overcurrent protection circuit, a closed-loop control link of "signal acquisition-comparison feedback-execution control" is formed. Specifically, the hardware-level current sampling and feedback comparison mechanism breaks through the traditional processor-dependent software protection mode, achieving rapid overcurrent response; the adjustable reference voltage design supports multi-threshold hierarchical protection, adapting to high-safety scenario requirements; the RC circuit achieves dynamic short-circuit protection, enabling the circuit to act as the master controller, using external signals to control the on / off state of the solenoid valve, collaboratively ensuring system safety and controllability, and giving the system external forced intervention capability; the modular architecture simplifies the component configuration at the drive level through multiple shared protection circuits, improving reliability while achieving circuit design compactness and functional integration.

[0007] To achieve the above objectives, this utility model provides the following technical solution:

[0008] A solenoid valve drive circuit with multi-functional overcurrent protection includes:

[0009] Several sets of solenoid valve drive circuits, several sets of voltage acquisition circuits, current sampling circuits and overcurrent protection circuits;

[0010] Several sets of solenoid valve drive circuits are connected to several sets of voltage acquisition circuits in a one-to-one correspondence. The solenoid valve drive circuit includes an input comparator, a MOSFET and a solenoid valve connected in sequence.

[0011] The voltage acquisition circuit is connected to the MOS transistor, and the voltage acquisition circuit is used to acquire the actual voltage signal of the corresponding solenoid valve coil.

[0012] One end of the current sampling circuit is connected to several sets of solenoid valve drive circuits, and the other end of the current sampling circuit is connected to the overcurrent protection circuit.

[0013] The overcurrent protection circuit includes a feedback comparator, the output of which is connected to the input of the input comparator. The input comparator controls the on / off state of the MOS transistor based on the circuit signal output by the feedback comparator, thereby controlling the operating state of the solenoid valve.

[0014] As an improvement, a reference voltage is connected to the non-inverting input of the feedback comparator, and the inverting input of the feedback comparator is connected to the current sampling circuit. The current sampling circuit outputs a voltage of V1, and the reference voltage outputs a voltage of V2. When V1 > V2, an overcurrent signal is triggered, and the output of the feedback comparator is low; otherwise, the output of the feedback comparator is high.

[0015] As an improvement, the solenoid valve drive circuit further includes an input signal, a first voltage divider resistor, and a second voltage divider resistor. The input signal, the first voltage divider resistor, and the second voltage divider resistor are all connected to the inverting input terminal of the input comparator. The non-inverting input terminal of the input comparator is connected to the output terminal of the feedback comparator. A first filter capacitor is connected in parallel between the output terminal and the non-inverting input terminal of the input comparator.

[0016] As an improvement, the output terminal of the input comparator is connected to the gate of the MOS transistor, and a pull-up resistor and a gate resistor are provided between the input comparator and the MOS transistor. One end of the solenoid valve is connected to the drain of the MOS transistor, and the other end of the solenoid valve is connected to the drive power supply.

[0017] As an improvement, the voltage at the inverting input terminal of the input comparator is V3, and the voltage at the non-inverting input terminal of the input comparator is V4. When V4 > V3, the output terminal of the input comparator outputs a high level, the gate of the MOS transistor is driven, and the solenoid valve works normally.

[0018] As an improvement, the overcurrent protection circuit further includes an RC circuit, which is connected in series with the input comparator and the feedback comparator, and is connected to the output terminal of the feedback comparator and the non-inverting input terminal of the input comparator, respectively.

[0019] As an improvement, the output of the feedback comparator is also connected to an enable control circuit, which includes a transistor and an external signal. The collector of the transistor is connected to the RC circuit, the emitter of the transistor is connected to the ground, and the base of the transistor is connected to the external signal.

[0020] As an improvement, the voltage of the external signal is V5. When V5 is high, the output of the RC circuit is low, which affects the gate drive signal of the MOS transistor to be low, thereby forcibly closing the solenoid valve.

[0021] As an improvement, the current sampling circuit includes a sampling resistor group, a current limiting resistor, and a second filter capacitor arranged in series. The sampling resistor group includes several groups of sampling resistors arranged in parallel. The sampling resistor group is connected to the source of the MOS transistor. The current limiting resistor is connected to the inverting input terminal of the feedback comparator. The second filter capacitor is connected to the ground port.

[0022] As an improvement, the voltage acquisition circuit is connected to a voltage clamping circuit, which is used to prevent the voltage acquisition circuit from being damaged by port overvoltage.

[0023] The beneficial effects of this utility model are as follows:

[0024] (1) The present invention adopts a pure hardware closed-loop overcurrent protection mechanism. The current sampling circuit collects the current signal in real time and compares it with the reference voltage through the feedback comparator. When the current exceeds the threshold, the feedback comparator outputs a low level, which quickly controls the input comparator to turn off the MOS transistor, thereby achieving a fast response. The RC circuit can ensure that the device is not damaged under long-term short circuit, breaking through the delay defect of traditional software processing and significantly improving reliability.

[0025] (2) In this utility model, multiple solenoid valve drive circuits share a set of current sampling and protection circuits, eliminating the need for separate drive chips and detection components for each circuit. This reduces the number of discrete components such as resistors and capacitors, saves board space, and lowers production costs. It is especially suitable for scenarios where multiple solenoid valves do not work simultaneously.

[0026] (3) The voltage acquisition circuit in this utility model monitors the actual voltage of the solenoid valve coil in real time. Combined with the voltage clamping circuit composed of diodes and current limiting resistors, it effectively suppresses transient overvoltages such as back electromotive force generated during the switching process, avoids damage to the port due to overvoltage, and the acquired voltage signal can also be fed back to the control system to form a closed-loop control, further improving reliability.

[0027] (4) This utility model uses a transistor and an external signal to form an enable control circuit, which can force all solenoid valves to close by an external signal and act as a master switch to flexibly control the overall working state; the RC circuit is set with a suitable charging time constant so that the system can work periodically with only a very short conduction time when short-circuited, which protects the device and maintains the basic monitoring function.

[0028] (5) The present invention has a modular drive circuit architecture, which can increase or decrease the drive unit according to the number of solenoid valves. The simplified structure of the input comparator and MOS tube can be adapted to different power requirements. It can control multiple main switches without additional power devices, and has strong versatility. It is suitable for various multi-peripheral drive scenarios with overcurrent protection requirements, such as industrial control and automotive electronics.

[0029] In summary, this utility model has the advantages of high efficiency, stability and safety, low cost and flexible control, and is especially suitable for the field of electromagnetic valve drive circuit technology. Attached Figure Description

[0030] Figure 1 This is a block diagram of the solenoid valve drive circuit of this utility model;

[0031] Figure 2 This is a circuit diagram of the solenoid valve drive circuit of this utility model;

[0032] Figure 3 This is a circuit diagram of the overcurrent protection circuit of this utility model;

[0033] Figure 4 This is a circuit diagram of the overcurrent protection circuit port of this utility model.

[0034] In the diagram: Solenoid valve drive circuit 1, input signal 10, input comparator 11, MOSFET 12, solenoid valve 13, first voltage divider resistor 14, second voltage divider resistor 15, third filter capacitor 16, pull-up resistor 17, gate resistor 18, voltage acquisition circuit 2, current sampling circuit 3, sampling resistor group 31, sampling resistor 311, current limiting resistor 32, second filter capacitor 33, overcurrent protection circuit 4, reference voltage 40, feedback comparator 41, RC circuit 42, enable control circuit 43, transistor 431, external signal 432, first filter capacitor 44, voltage clamping circuit 5. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0036] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] Example 1:

[0039] like Figures 1-4 As shown, a solenoid valve drive circuit with multi-functional overcurrent protection includes:

[0040] Several sets of solenoid valve drive circuits 1, several sets of voltage acquisition circuits 2, current sampling circuits 3, and overcurrent protection circuits 4;

[0041] Several groups of solenoid valve drive circuits 1 are connected to several groups of voltage acquisition circuits 2 in a one-to-one correspondence. The solenoid valve drive circuit 1 includes an input comparator 11, a MOS transistor 12 and a solenoid valve 13 connected in sequence.

[0042] The voltage acquisition circuit 2 is connected to the MOS transistor 12, and the voltage acquisition circuit 2 is used to acquire the actual voltage signal of the coil of the corresponding solenoid valve 13.

[0043] One end of the current sampling circuit 3 is connected to several groups of solenoid valve drive circuits 1 to collect the current data of each solenoid valve 13 in real time. The other end of the current sampling circuit 3 is connected to the overcurrent protection circuit 4 to transmit the collected current signal to the overcurrent protection circuit 4.

[0044] The overcurrent protection circuit 4 includes a feedback comparator 41. The output of the feedback comparator 41 is connected to the input of the input comparator 11. The feedback comparator 41 receives the current signal from the current sampling circuit 3 and compares it with a preset safe current threshold. Once the actual current exceeds the safe threshold, it is determined to be an overcurrent state. The feedback comparator 41 will quickly output a corresponding circuit signal. The input comparator 11 controls the on / off state of the MOSFET 12 according to the circuit signal output by the feedback comparator 41, thereby controlling the operating state of the solenoid valve 13. When an overcurrent occurs, the input comparator 11 will control the MOSFET 12 to turn off, cutting off the current supply to the solenoid valve 13, thereby avoiding serious consequences such as damage to the solenoid valve and circuit burnout caused by overcurrent. This achieves a multi-functional overcurrent protection. Through the coordinated work of various circuits, this drive circuit can not only stably drive the solenoid valve 13, but also effectively protect the solenoid valve 13 and the entire circuit system, improving the reliability and safety of the system.

[0045] Furthermore, a reference voltage 40 is connected to the non-inverting input of the feedback comparator 41, which provides a standard reference for the feedback comparator 41, enabling the circuit to accurately determine whether the operating current of the solenoid valve is abnormal. The inverting input of the feedback comparator 41 is connected to the current sampling circuit 3, and the output voltage of the current sampling circuit 3 is V1, which reflects the actual current status of each solenoid valve 13 in real time. The output voltage of the reference voltage 40 is V2. When V1>V2, an overcurrent signal is triggered, and the output of the feedback comparator 41 is low. After the current signal is transmitted to the input comparator 11, it will change the output state of the input comparator 11, thereby controlling the MOSFET 12 to be turned off and quickly cutting off the current supply to the solenoid valve 13. Conversely, the output of the feedback comparator 41 is high, which will not change the original control logic of the input comparator 11. The MOSFET 12 will still perform the on and off operations according to the predetermined external control signal to ensure the stable operation of the solenoid valve 13.

[0046] Through the precise comparison and rapid response of V1 and V2 by the feedback comparator 41, the entire solenoid valve drive circuit realizes timely monitoring and reliable protection of overcurrent conditions. At the same time, the flexible setting of the reference voltage 40 also enables the protection mechanism to be adapted to solenoid valves of different specifications and operating requirements, greatly improving the versatility and practicality of the circuit system.

[0047] It should be noted that the input comparator 11 outputs a specific level signal, which directly acts on the gate of the MOSFET 12. As a key power device in the circuit, the MOSFET 12 has advantages such as fast switching speed and low on-resistance. Under the control of the gate signal, the MOSFET 12 switches between on and off states. When the MOSFET 12 is on, the current from the drive power supply can flow smoothly through the solenoid valve 13, making the solenoid valve 13 work normally. When the MOSFET 12 is off, the current path is cut off, and the solenoid valve 13 stops working.

[0048] It should be further explained that the input comparator 11 is also connected to a signal adjustment circuit. In the scenario of solenoid valve driving, when a rapid response is required for fault signals such as overcurrent and overvoltage, the operational amplifier can quickly amplify and transmit the signal to trigger protection; while during normal driving, it can stably output a smooth signal to avoid frequent malfunctions of the solenoid valve and balance response speed and stability.

[0049] A first filter capacitor 44 is connected between the reference voltage 40 and the current sampling circuit 3. During the process of the current sampling circuit 3 acquiring the working current of the solenoid valve in real time and converting it into a voltage signal V1, the output voltage signal may be mixed with high-frequency noise and ripple due to electromagnetic interference, transient response of other components in the circuit, etc. If these interference signals are directly input to the inverting input terminal of the feedback comparator 41 and compared with the stable voltage V2 output by the reference voltage 40, it may cause the feedback comparator 41 to make a misjudgment. For example, a momentary voltage spike may cause V1 to be temporarily greater than V2, triggering an incorrect overcurrent signal, causing the circuit to malfunction and affecting the normal operation of the solenoid valve.

[0050] The first filter capacitor 44 utilizes the characteristic of a capacitor to "pass AC and block DC" to effectively suppress the above-mentioned interference. For high-frequency noise and ripple in the voltage signal output by the current sampling circuit 3, the first filter capacitor 44 presents a low impedance state, allowing these high-frequency components to flow into the ground terminal through the capacitor. For the DC component representing the actual current, the capacitor presents a high impedance state, preventing it from passing through, thereby ensuring that the voltage signal that truly reflects the current situation can be smoothly transmitted to the feedback comparator 41.

[0051] Furthermore, the solenoid valve drive circuit 1 also includes an input signal 10, a first voltage divider resistor 14, and a second voltage divider resistor 15. The input signal 10, the first voltage divider resistor 14, and the second voltage divider resistor 15 are all connected to the inverting input terminal of the input comparator 11. The first voltage divider resistor 14 and the second voltage divider resistor 15 form a voltage divider circuit, which adjusts the voltage of the input signal 10 according to a certain ratio and then sends it to the inverting input terminal of the input comparator 11. The purpose of this operation is to set the comparison reference voltage of the input comparator 11. By reasonably configuring the resistance values ​​of the two resistors, the threshold value of the input signal 10 participating in the comparison can be flexibly adjusted to ensure that only signals that meet specific voltage requirements can trigger subsequent circuit actions, thereby providing precise control conditions for the drive of the solenoid valve 13. In addition, when the input signal 10 rises abnormally, the first voltage divider resistor 14 and the second voltage divider resistor 15 limit the voltage of the input comparator 11 from not exceeding the safe range.

[0052] The non-inverting input terminal of the input comparator 11 is connected to the output terminal of the feedback comparator 41. The input comparator 11 compares the adjusted input signal 10 at the inverting input terminal with the feedback signal at the non-inverting input terminal, and outputs a corresponding level signal according to the magnitude relationship between the two. This comparison process realizes the real-time verification of the working state of the solenoid valve 13 and the input signal 10, ensuring that the solenoid valve works as expected.

[0053] A third filter capacitor 16 is connected in parallel with the non-inverting input terminal of the input comparator 11. The third filter capacitor 16 serves to filter and stabilize the output signal. During the operation of the circuit, the signal transmission and comparison process may be affected by electromagnetic interference or transient changes in the circuit itself, resulting in voltage fluctuations or spike noise. The third filter capacitor 16 uses its charging and discharging characteristics to absorb and smooth these interference signals, making the output signal of the input comparator 11 more stable, avoiding malfunction of the solenoid valve 13 due to signal fluctuations, and enhancing the anti-interference capability and working stability of the solenoid valve drive circuit.

[0054] The output terminal of the input comparator 11 is connected to the gate of the MOS transistor 12. The level signal output by the input comparator 11 directly determines the conduction and cutoff state of the MOS transistor 12. When the input comparator 11 outputs a high level, the gate of the MOS transistor 12 receives sufficient driving voltage, thereby conducting and forming a circuit. When the output is low, the MOS transistor 12 is cut off, cutting off the circuit.

[0055] A pull-up resistor 17 and a gate resistor 18 are connected between the input comparator 11 and the MOSFET 12. The pull-up resistor 17 is connected to the power supply. When the input comparator 11 outputs a low level, the pull-up resistor 17 pulls the gate of the MOSFET 12 to the power supply voltage, ensuring that the MOSFET 12 is reliably turned off. When the input comparator 11 outputs a high level and a transition occurs, the pull-up resistor 17 can limit the gate current, preventing damage to the MOSFET 12 due to a sudden excessive current surge, thus protecting the device and stabilizing the gate voltage.

[0056] The gate resistor 18 is connected in series between the output of the input comparator 11 and the gate of the MOSFET 12. Since the gate of the MOSFET 12 has parasitic capacitance, it will generate high-frequency oscillations during the switching process. The gate resistor 18 effectively suppresses these oscillations and reduces electromagnetic interference by increasing damping. At the same time, it can also adjust the switching speed of the MOSFET 12, avoid sudden changes in voltage and current during switching, and ensure the stability and reliability of the circuit operation.

[0057] One end of the solenoid valve 13 is connected to the drain of the MOS transistor 12, and the other end of the solenoid valve 13 is connected to the driving power supply. When the MOS transistor 12 is turned on, the current of the driving power supply flows through the solenoid valve 13, causing the internal coil to generate electromagnetic force, attracting the valve core to move and realizing the opening of the solenoid valve 13. When the MOS transistor 12 is turned off, the current is interrupted, the solenoid valve 13 loses electromagnetic force, and the valve core returns to its original position under the action of the reset mechanism, closing the solenoid valve 13 and cutting off the passage, thereby realizing precise switching control of the solenoid valve 13.

[0058] It should be noted that a diode is connected in parallel across the two ends of the solenoid valve 13. When the MOSFET 12 changes from being on to being off, the inductance of the solenoid valve 13 will generate a reverse electromotive force. At this time, the diode provides a discharge path for the reverse electromotive force, allowing the current in the inductor to continue flowing. This prevents the MOSFET 12 from being broken down or other components from being damaged due to excessively high voltage spikes. This protection mechanism can effectively extend the circuit life, reduce electromagnetic interference, and ensure the stable operation of the solenoid valve 13.

[0059] Furthermore, the voltage at the inverting input terminal of the input comparator 11 is V3, and the voltage at the non-inverting input terminal of the input comparator 11 is V4. When V4 > V3, the output terminal of the input comparator 11 outputs a high level, the gate of the MOS transistor 12 is driven, and the solenoid valve 13 works normally.

[0060] Furthermore, the overcurrent protection circuit 4 also includes an RC circuit 42, which is connected in series with the input comparator 11 and the feedback comparator 41. The RC circuit 42 is connected to the output terminal of the feedback comparator 41 and the non-inverting input terminal of the input comparator 11, respectively.

[0061] The RC circuit 42 filters the signal output by the feedback comparator 41, removing high-frequency noise and preventing it from interfering with the normal operation of the input comparator 11. This ensures that the input comparator 11 receives a smooth, stable, and effective signal, thereby improving the anti-interference capability of the entire overcurrent protection circuit. On the other hand, the RC circuit 42 has a delay characteristic. When the current in the circuit changes abruptly and the feedback comparator 41 quickly generates a change in the output signal, the RC circuit 42 will not immediately transmit the changed signal to the input comparator 11. Instead, it will delay the signal for a certain period of time. This characteristic can effectively prevent false triggering of protection actions caused by instantaneous current fluctuations. Only when the current remains abnormal and exceeds the delay time set by the RC circuit 42 will the input comparator 11 make a comparison and judgment based on a stable signal, thereby triggering a reliable current protection action and ensuring the stability and reliability of the circuit operation.

[0062] In practical applications, by designing the charging time constant of the RC circuit 42 at the output of the feedback comparator, fine control of signal transmission can be achieved. When the circuit encounters a short circuit fault, the specific time constant setting can significantly shorten the effective drive ratio time within one cycle. This means that even if the system is in a short circuit state, the key components will not operate at high power for a long time, thereby avoiding damage caused by overheating and other problems. This ensures that the system can still operate stably for a long time under extreme short circuit conditions, greatly enhancing the reliability and tolerance of the circuit.

[0063] In addition, an enable control circuit 43 is connected to the output of the feedback comparator 41. The enable control circuit 43 includes a transistor 431 and an external signal 432. The collector of the transistor 431 is connected to the RC circuit 42, the emitter of the transistor 431 is connected to the ground, and the base of the transistor 431 is connected to the external signal 432. By controlling the on / off state of the transistor 431 through the external signal 432, the enable control circuit 43 can actively intervene in the signal transmission path of the RC circuit 42. When the external signal 432 is high, the transistor 431 is turned on, pulling the output of the RC circuit 42 low to ground, cutting off the effective drive signal of the input comparator 11, and forcibly shutting down the protection circuit. When the external signal 432 is low, the transistor 431 is turned off, the signal of the RC circuit 42 can be transmitted normally to the input comparator 11, and the protection function returns to normal operation.

[0064] This enable control circuit 43 based on transistor 431 upgrades the passive protection mechanism with a fixed threshold to an active protection system that can be externally adjusted, significantly enhancing the flexibility and adaptability of the overcurrent protection circuit. It is especially suitable for complex power electronic systems that require dynamic adjustment of protection strategies.

[0065] Furthermore, the voltage of the external signal 432 is V5. When V5 is high, the output of the RC circuit 42 is low, which affects the gate drive signal of the MOS transistor 12 to be low, thereby forcibly closing the solenoid valve 13.

[0066] Furthermore, the current sampling circuit 3 includes a sampling resistor group 31, a current limiting resistor 32, and a second filter capacitor 33 arranged in series. The sampling resistor group 31 includes several groups of sampling resistors 311 arranged in parallel. The multiple groups of sampling resistors 311 realize accurate sampling of the main circuit current. The parallel structure can reduce the overall sampling resistance value and reduce power loss. It can also improve the sampling accuracy by reasonably selecting the resistance parameters, ensuring that a stable and reliable voltage feedback signal can be obtained under different load currents.

[0067] The sampling resistor group 31 is connected to the source of the MOS transistor 12. When the circuit current passes through the sampling resistor group 31, a voltage drop proportional to the current is generated across its terminals. This voltage drop is transmitted to the feedback comparator 41 as a feedback signal, realizing the linear conversion from current signal to voltage signal, and providing a basis for subsequent comparison and judgment.

[0068] The current-limiting resistor 32 is connected to the inverting input terminal of the feedback comparator 41, and the second filter capacitor 33 is connected to the grounding port. On the one hand, the current-limiting resistor 32 limits the current flowing into the feedback comparator 41 to prevent excessive current from damaging the comparator. On the other hand, together with the second filter capacitor 33, it forms an RC filter network to perform secondary filtering on the sampled signal, further filtering out high-frequency interference and switching noise, and improving signal quality.

[0069] It should be noted that the voltage acquisition circuit 2 is connected to a voltage clamping circuit 5. The voltage clamping circuit 5 is used to prevent the voltage acquisition circuit 2 from being damaged by port overvoltage. When the port voltage exceeds the set threshold, the clamping circuit immediately enters the conduction state, diverting the excess energy to the ground or power supply terminal, ensuring that the input of the voltage acquisition circuit 2 is always kept below the withstand voltage.

[0070] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A solenoid valve drive circuit with multi-functional overcurrent protection, characterized in that, include: Several sets of solenoid valve drive circuits (1), several sets of voltage acquisition circuits (2), current sampling circuits (3) and overcurrent protection circuits (4); Several sets of solenoid valve drive circuits (1) are connected to several sets of voltage acquisition circuits (2) in a one-to-one correspondence. The solenoid valve drive circuit (1) includes an input comparator (11), a MOS transistor (12) and a solenoid valve (13) connected in sequence. The voltage acquisition circuit (2) is connected to the MOS transistor (12), and the voltage acquisition circuit (2) is used to acquire the actual voltage signal of the coil of the corresponding solenoid valve (13); One end of the current sampling circuit (3) is connected to several sets of solenoid valve drive circuits (1), and the other end of the current sampling circuit (3) is connected to the overcurrent protection circuit (4). The overcurrent protection circuit (4) includes a feedback comparator (41). The output of the feedback comparator (41) is connected to the input of the input comparator (11). The input comparator (11) controls the connection state of the MOS transistor (12) according to the circuit signal output by the feedback comparator (41), thereby controlling the operating state of the solenoid valve (13).

2. The solenoid valve drive circuit with multi-functional overcurrent protection as described in claim 1, characterized in that: The non-inverting input of the feedback comparator (41) is connected to a reference voltage (40), and the inverting input of the feedback comparator (41) is connected to the current sampling circuit (3). The output voltage of the current sampling circuit (3) is V1, and the output voltage of the reference voltage (40) is V2. When V1>V2, an overcurrent signal is triggered, and the output of the feedback comparator (41) is low. Conversely, the output of the feedback comparator (41) is high.

3. The solenoid valve drive circuit with multi-functional overcurrent protection as described in claim 1, characterized in that: The solenoid valve drive circuit (1) further includes an input signal (10), a first voltage divider resistor (14) and a second voltage divider resistor (15). The input signal (10), the first voltage divider resistor (14) and the second voltage divider resistor (15) are all connected to the inverting input terminal of the input comparator (11). The non-inverting input terminal of the input comparator (11) is connected to the output terminal of the feedback comparator (41). A third filter capacitor (16) is connected in parallel between the output terminal and the non-inverting input terminal of the input comparator (11).

4. The solenoid valve drive circuit with multi-function overcurrent protection according to claim 1, characterized in that: The output terminal of the input comparator (11) is connected to the gate of the MOS transistor (12). A pull-up resistor (17) and a gate resistor (18) are connected between the input comparator (11) and the MOS transistor (12). One end of the solenoid valve (13) is connected to the drain of the MOS transistor (12), and the other end of the solenoid valve (13) is connected to the drive power supply.

5. A solenoid valve drive circuit with multi-function overcurrent protection as described in claim 1, characterized in that: The voltage at the inverting input terminal of the input comparator (11) is V3, and the voltage at the non-inverting input terminal of the input comparator (11) is V4. When V4>V3, the output terminal of the input comparator (11) outputs a high level, the gate of the MOS transistor (12) is driven, and the solenoid valve (13) works normally.

6. A solenoid valve drive circuit with multi-functional overcurrent protection as described in claim 1, characterized in that: The overcurrent protection circuit (4) further includes an RC circuit (42), which is connected in series with the input comparator (11) and the feedback comparator (41). The RC circuit (42) is connected to the output terminal of the feedback comparator (41) and the non-inverting input terminal of the input comparator (11), respectively.

7. A solenoid valve drive circuit with multi-function overcurrent protection as described in claim 6, characterized in that: The output of the feedback comparator (41) is also connected to an enable control circuit (43). The enable control circuit (43) includes a transistor (431) and an external signal (432). The collector of the transistor (431) is connected to the RC circuit (42), the emitter of the transistor (431) is connected to the ground port, and the base of the transistor (431) is connected to the external signal (432).

8. A solenoid valve drive circuit with multi-function overcurrent protection as described in claim 7, characterized in that: The voltage of the external signal (432) is V5. When V5 is high, the output of the RC circuit (42) is low, which affects the gate drive signal of the MOS transistor (12) to be low, thereby forcibly closing the solenoid valve (13).

9. A solenoid valve drive circuit with multi-functional overcurrent protection as described in claim 1, characterized in that: The current sampling circuit (3) includes a sampling resistor group (31), a current limiting resistor (32) and a second filter capacitor (33) arranged in series. The sampling resistor group (31) includes several groups of sampling resistors (311) arranged in parallel. The sampling resistor group (31) is connected to the source of the MOS transistor (12). The current limiting resistor (32) is connected to the inverting input terminal of the feedback comparator (41). The second filter capacitor (33) is connected to the ground port.

10. A solenoid valve drive circuit with multi-functional overcurrent protection as described in claim 1, characterized in that: The voltage acquisition circuit (2) is connected to a voltage clamping circuit (5), which is used to prevent the voltage acquisition circuit (2) from being damaged by port overvoltage.

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