Inductive load driving circuit and vehicle

Abstract

This utility model provides an inductive load drive circuit and vehicle. The circuit includes: a filter anti-reverse circuit, a switching circuit, a filter support circuit, a voltage detection circuit, a first overcurrent detection circuit, a freewheeling circuit, a first switching element, a drive circuit, a second overcurrent detection circuit, a current detection circuit, a fault latching circuit, and a control component. After being filtered and protected against reverse flow, the power supply is controlled by the switching circuit for on / off switching. The load current is regulated by the first switching element and detected by dual-path overcurrent detection. The freewheeling circuit releases energy when the inductive load is turned off. Voltage and current detection signals are fed back to the control component to achieve closed-loop control. The fault latching circuit locks the output in case of abnormalities to ensure safety. Based on a low-side drive architecture, this circuit integrates a high-side power switch, high / low-side overcurrent detection, a freewheeling path, current closed-loop control, and a fault latching mechanism, achieving dual protection against power supply and ground short circuits, effectively improving the circuit's reliability and safety.

Description

Technical Field

[0001] This utility model relates to the field of vehicle electronic control, and more specifically, to an inductive load drive circuit and a vehicle in the field of vehicle electronic control. Background Technology

[0002] In vehicle electronic systems, the reliable driving of inductive loads (such as electromagnetic bridge disconnect devices, electromagnetic door catches, electromagnetic differential locks, and DC brushed oil / water pump motors) is a key aspect of ensuring the functional safety of the entire vehicle. With the development of vehicle intelligence and electrification, higher requirements are placed on the current capability, response speed, environmental adaptability, and fault tolerance of actuator drive circuits, especially the need to achieve stable and safe control even under extreme operating conditions.

[0003] In related technologies, vehicle-mounted inductive load drives generally adopt high-side drive or low-side drive schemes. High-side drive achieves load management by controlling the on / off state of the power supply side, and usually relies on a dedicated high-side drive chip; while low-side drive regulates the load current by controlling the on / off state of the ground-side MOSFET, and is widely used in unidirectional speed regulation or switching actuator control.

[0004] However, high-side driver chips generally suffer from drawbacks such as large static current, high sleep power consumption, limited control frequency, narrow current detection bandwidth and insufficient accuracy, while low-side drivers cannot effectively identify and protect the output terminal from power supply short circuit faults, which urgently need to be addressed. Utility Model Content

[0005] This invention provides an inductive load drive circuit and vehicle. Based on a low-side drive architecture, the circuit integrates a high-side power switch, high / low-side overcurrent detection, freewheeling path, current closed-loop control, and fault latching mechanism to achieve dual protection against power supply and ground short circuits, effectively improving the reliability and safety of the circuit.

[0006] In a first aspect, an inductive load drive circuit is provided, comprising: a filter anti-reverse circuit, a switching circuit, a filter support circuit, a voltage detection circuit, a first overcurrent detection circuit, a freewheeling circuit, a first switching element, a drive circuit, a second overcurrent detection circuit, a current detection circuit, a fault latching circuit, and a control component, wherein... The input terminal of the filter anti-reverse circuit is connected to the power supply component, and the output terminal of the filter anti-reverse circuit is connected to the first input terminal of the switching circuit. The second input terminal of the switching circuit is connected to the first output terminal of the fault latch circuit, and the output terminal of the switching circuit is connected to the input terminal of the filter support circuit. The output terminal of the filter support circuit is connected to one end of the voltage detection circuit and the input terminal of the first overcurrent detection circuit, respectively. The other end of the voltage detection circuit is connected to the control component; The first output terminal of the first overcurrent detection circuit is connected to one end of the freewheeling circuit; The other end of the freewheeling circuit is connected to the first end of the first switching element; The control terminal of the first switch is connected to the output terminal of the drive circuit, and the second terminal of the first switch is connected to the first terminal of the second overcurrent detection circuit. The input terminal of the drive circuit is connected to the control component, and the third terminal of the drive circuit is connected to the second output terminal of the fault latch circuit. The second terminal of the second overcurrent detection circuit is connected to one terminal of the current detection circuit; The other end of the current detection circuit is connected to the control component; The input terminal of the fault latch circuit is connected to the control component.

[0007] The above technical solution achieves high-reliability drive for inductive loads based on a low-side drive architecture, with dual overcurrent detection capabilities for power supply short circuits and ground short circuits. Combined with freewheeling paths, closed-loop current control, and fault latching mechanisms, it supports load currents up to 10A under wide voltage (9~16V) and full temperature range (-40~125℃), effectively improving the safety, stability, and self-protection capabilities of vehicle-mounted electromagnetic actuators or DC brushed motor drives.

[0008] In conjunction with the first aspect, in some possible implementations, the filter anti-reverse circuit includes: a second switch, a first resistor, first to sixth capacitors, a first Zener diode, and a second Zener diode, wherein... The first end of the second switch is connected to the positive terminal of the power supply component, the second end of the second switch is connected to the switching circuit, and the control terminal of the second switch is connected to one end of the first resistor. The other end of the first resistor is connected to the negative terminal of the power supply component; One end of the first capacitor is connected to the connection node between the second switch and the power supply component, and the other end of the first capacitor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the negative terminal of the power supply component; One end of the third capacitor is connected to the connection node between the second switch and the power supply component, and the other end of the third capacitor is connected to one end of the fourth capacitor. The other end of the fourth capacitor is connected to the negative terminal of the power supply component; The cathode of the first Zener diode is connected to the connection node between the second switch and the switching circuit, and the anode of the first Zener diode is connected to the connection node between the second switch and the first resistor and one end of the fifth capacitor. The other end of the fifth capacitor is connected to the negative terminal of the power supply component; The cathode of the second Zener diode is connected to the cathode of the first Zener diode and the switching circuit, respectively, and the anode of the second Zener diode is connected to the negative terminal of the power supply component. One end of the sixth capacitor is connected to the cathode of the second Zener diode and the switching circuit, and the other end of the sixth capacitor is connected to the negative terminal of the power supply component.

[0009] Through the above technical solution, the filter anti-reverse circuit can not only effectively suppress high-frequency noise and voltage fluctuations at the power input terminal, but also automatically cut off the circuit when the power supply polarity is reversed, preventing damage to the subsequent circuit.

[0010] In combination with the first aspect and the above-described implementations, in some possible implementations, the switching circuit includes: second to fifth resistors, a third switching element, a third Zener diode, a seventh capacitor, and a fourth switching element, wherein, One end of the second resistor is connected to the first output terminal of the fault latch circuit, and the other end of the second resistor is connected to the control terminal of the third switch. One end of the third resistor is connected to the connection node between the second resistor and the third switch, and the other end of the third resistor is connected to the ground node; The first end of the third switch is connected to one end of the fourth resistor, and the second end of the third switch is connected to the grounding node; One end of the fourth resistor is connected to one end of the fifth resistor; The other end of the fifth resistor is connected to one end of the sixth capacitor; The anode of the third Zener diode is connected to the connection node between the fifth resistor and the fourth resistor, and the cathode of the third Zener diode is connected to one end of the sixth capacitor. One end of the seventh capacitor is connected to the connection node between the fifth resistor and the fourth resistor, and the other end of the seventh capacitor is connected to one end of the sixth capacitor; The control terminal of the fourth switch is connected to the connection node between the fifth resistor and the fourth resistor, the first terminal of the fourth switch is connected to one end of the sixth capacitor, and the second terminal of the fourth switch is connected to the filter support circuit.

[0011] Through the above technical solution, the switching circuit uses the third switching device to receive the fault latching signal to control the conduction state of the fourth switching device, thereby realizing the controlled switching of the high-side power supply; the third Zener diode works in conjunction with the multi-stage RC (Resistance Capacitance) network to clamp and filter the driving voltage, ensuring that the gate voltage of the fourth switching device is stable and reliable, thereby quickly cutting off the power supply path in the event of an overcurrent or short circuit fault, improving the system response speed and safety.

[0012] Combining the first aspect and the above-described implementation methods, in some possible implementations, the filter support circuit includes: a first inductor and eighth to tenth capacitors, wherein, One end of the first inductor is connected to the second end of the fourth switching device, and the other end of the first inductor is connected to the voltage detection circuit and the first overcurrent detection circuit, respectively. One end of the eighth capacitor is connected to the connection node between the first inductor and the fourth switch, and the other end of the eighth capacitor is connected to the ground node. One end of the ninth capacitor is connected to the other end of the first inductor, and the other end of the ninth capacitor is connected to the grounding node. One end of the tenth capacitor is connected to the other end of the first inductor, and the other end of the tenth capacitor is connected to the grounding node.

[0013] Through the above technical solution, the filter support circuit uses the first inductor and the eighth to tenth capacitors to form an LC (Inductance Capacitance) multi-stage filter network, which effectively suppresses power supply ripple and high-frequency interference, provides a stable and low-noise power supply node for subsequent voltage detection, overcurrent detection and load driving, and enhances the system's ability to resist power supply transient fluctuations, ensuring the reliable operation of inductive loads in complex vehicle electromagnetic environments.

[0014] In combination with the first aspect and the above-described implementations, in some possible implementations, the voltage detection circuit includes: a sixth resistor, a seventh resistor, and an eleventh capacitor, wherein, One end of the sixth resistor is connected to the other end of the first inductor, and the other end of the sixth resistor is connected to the control component; One end of the seventh resistor is connected to the connection node between the sixth resistor and the control component, and the other end of the seventh resistor is connected to the grounding node; One end of the eleventh capacitor is connected to the connection node between the sixth resistor and the control component, and the other end of the eleventh capacitor is connected to the grounding node.

[0015] Through the above technical solution, the voltage detection circuit uses the sixth and seventh resistors to form a voltage divider network to sample the filtered power supply voltage, and uses the eleventh capacitor to filter out high-frequency noise, sending a stable and accurate voltage feedback signal to the control component for real-time monitoring of power supply status and supporting closed-loop control or fault diagnosis, thereby improving the system's ability to perceive and respond to power supply anomalies.

[0016] In combination with the first aspect and the above-described implementations, in some possible implementations, the first overcurrent detection circuit includes: an eighth to a twelfth resistor, a fifth switch, and a sixth switch, wherein... One end of the eighth resistor is connected to the connection node between the first inductor and the sixth resistor, and the other end of the eighth resistor is connected to one end of the ninth resistor and the freewheeling circuit. The other end of the ninth resistor is connected to the control terminal of the fifth switch. The first end of the fifth switch is connected to one end of the eighth resistor, and the second end of the fifth switch is connected to one end of the tenth resistor; The other end of the tenth resistor is connected to one end of the eleventh resistor; The other end of the eleventh resistor is connected to the grounding node; The control terminal of the sixth switch is connected to the connection node between the tenth resistor and the eleventh resistor, the first terminal of the sixth switch is connected to the grounding node, and the second terminal of the sixth switch is connected to one end of the twelfth resistor. The other end of the twelfth resistor is connected to the power supply access node.

[0017] Through the above technical solution, the first overcurrent detection circuit uses the fifth and sixth switching devices to form a high-side current detection and signal conditioning structure. When the load current is abnormal and the high-side voltage drops, the fifth switching device is triggered to conduct through the voltage division of the eighth to eleventh resistors, which in turn drives the sixth switching device to output an overcurrent indication signal to the control component. This enables rapid and reliable detection of high-side faults such as power supply short circuits at the output terminal, providing a key criterion for dual short-circuit protection.

[0018] In combination with the first aspect and the above-described implementations, in some possible implementations, the freewheeling circuit includes: a freewheeling diode and a second inductor, wherein, One end of the freewheeling diode is connected to the other end of the eighth resistor and one end of the second inductor, respectively, and the other end of the freewheeling diode is connected to the other end of the first switch and the other end of the second inductor, respectively.

[0019] Through the above technical solution, the freewheeling circuit uses the freewheeling diode and the second inductor to form an energy release path, providing a low-impedance freewheeling loop for the back electromotive force generated by the inductive load when the first switching device is turned off, effectively suppressing voltage spikes and protecting the switching device from breakdown damage. At the same time, the second inductor and the diode work together to optimize the dynamic response of the freewheeling process, improving system reliability and electromagnetic compatibility.

[0020] In combination with the first aspect and the above-described implementations, in some possible implementations, the second overcurrent detection circuit includes: thirteenth to fifteenth resistors and a seventh switching element, wherein, One end of the thirteenth resistor is connected to the second end of the first switching element, and the other end of the thirteenth resistor is connected to the grounding node; One end of the fourteenth resistor is connected to one end of the thirteenth resistor, and the other end of the fourteenth resistor is connected to the control terminal of the seventh switch. The first end of the seventh switch is connected to the grounding node, and the second end of the seventh switch is connected to one end of the twelfth resistor; One end of the fifteenth resistor is connected to the connection node between the fourteenth resistor and the seventh switch, and the other end of the fifteenth resistor is connected to the grounding node.

[0021] Through the above technical solution, the second overcurrent detection circuit uses the thirteenth resistor as the low-side current sampling resistor. When the load current is too large, its voltage drop drives the seventh switch to conduct through the fourteenth resistor, and outputs an overcurrent signal to the fault latching circuit. The fifteenth resistor provides bias stability and anti-interference capability, thereby realizing fast hardware-level detection of low-side faults such as short circuit to ground at the output terminal. Together with the first overcurrent detection circuit, it forms a bidirectional short-circuit protection mechanism.

[0022] In combination with the first aspect and the above-described implementations, in some possible implementations, the current detection circuit includes: sixteenth to nineteenth resistors, twelfth to fourteenth capacitors, and a comparison unit, wherein, One end of the sixteenth resistor is connected to the grounding node, and the other end of the sixteenth resistor is connected to the first input terminal of the comparison unit; One end of the seventeenth resistor is connected to the grounding node, and the other end of the seventeenth resistor is connected to the second input terminal of the comparison unit; One end of the eighteenth resistor is connected to the second input terminal of the comparator unit, and the other end of the eighteenth resistor is connected to the output terminal of the comparator unit. One end of the twelfth capacitor is connected to the second input terminal of the comparator unit, and the other end of the twelfth capacitor is connected to the output terminal of the comparator unit. One end of the thirteenth capacitor is connected to the first input terminal of the comparison unit, and the other end of the thirteenth capacitor is connected to the ground node. One end of the nineteenth resistor is connected to the first input terminal of the comparison unit, and the other end of the nineteenth resistor is connected to the ground node; One end of the fourteenth capacitor is connected to the grounding node, and the other end of the fourteenth capacitor is connected to the output terminal of the comparison unit. The power supply terminal of the comparison unit is connected to the power access node, the ground terminal of the comparison unit is connected to the ground node, and the output terminal of the comparison unit is connected to the power access node and the control component respectively.

[0023] Through the above technical solution, the current detection circuit constitutes a differential subtractor structure based on the comparison unit. It uses the sixteenth to nineteenth resistors and the twelfth to fourteenth capacitors to achieve precise differential amplification and filtering of the voltage across the low-side sampling resistor (thirteenth resistor), and outputs an analog signal proportional to the load current to the control component, thereby supporting high-precision closed-loop current control and providing a reliable basis for overcurrent judgment and dynamic adjustment at the software level.

[0024] In a second aspect, a vehicle is provided, including the inductive load drive circuit described in the above embodiments. Attached Figure Description

[0025] Figure 1 A schematic diagram of the structure of the inductive load drive circuit provided in an embodiment of this utility model; Figure 2 This is a schematic diagram of the specific connection structure of an inductive load drive circuit according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the truth table of a positive edge-triggered D-type flip-flop according to an embodiment of the present invention. Detailed Implementation

[0026] The technical solution of this utility model will be clearly and thoroughly described below with reference to the accompanying drawings. In the description of the embodiments of this utility model, unless otherwise stated, " / " indicates "or," for example, A / B can mean A or B. "And / or" in the text is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. Furthermore, in the description of the embodiments of this utility model, "multiple" refers to two or more than two.

[0027] Hereinafter, the terms "first" and "second" are used for descriptive purposes only and should not be construed as implying or suggesting relative importance or implicitly indicating 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.

[0028] In existing automotive inductive load drive technologies, a common approach is to use discrete low-side drivers combined with external protection devices or rely on integrated high-side driver ICs. These designs typically implement overcurrent detection, short-circuit protection, and drive control functions separately, or are highly dependent on dedicated chips from specific manufacturers. For example, some systems determine overcurrent solely through a low-side MOSFET connected in series with a sampling resistor and MCU (Microcontroller Unit) software; others use high-side driver ICs for diagnostics.

[0029] However, the above solutions have obvious limitations: on the one hand, pure software protection has a slow response and cannot shut down in time when a short circuit to the power supply occurs, which can easily lead to the burning of MOSFETs or circuits; on the other hand, the low-side architecture is inherently lacking in the ability to detect high-side short circuits because the high-side load is always connected to the power supply, while the high-side drive is difficult to balance the requirements of high current output and low power consumption sleep mode.

[0030] Based on the above problems, this utility model proposes an inductive load drive circuit that integrates high / low-side collaborative detection, hardware latching protection, and closed-loop current regulation. While retaining the advantages of low-side drive in terms of low cost and ease of driving, it achieves bidirectional short-circuit protection, rapid fault isolation, and high-reliability operation through innovative circuit topology.

[0031] Figure 1 This is a schematic diagram of the structure of an inductive load driving circuit provided in an embodiment of this utility model.

[0032] For example, such as Figure 1As shown, the inductive load drive circuit 10 includes: a reverse filtering circuit 100, a switching circuit 200, a filter support circuit 300, a voltage detection circuit 400, a first overcurrent detection circuit 500, a freewheeling circuit 600, a first switch 700, a drive circuit 800, a second overcurrent detection circuit 900, a current detection circuit 1000, a fault latching circuit 1100, and a control component 1200. The input terminal of the reverse filtering circuit 100 is connected to the power supply component, and the output terminal of the reverse filtering circuit 100 is connected to the first input terminal of the switching circuit 200. The second input terminal of the switching circuit 200 is connected to the first output terminal of the fault latching circuit 1100, and the output terminal of the switching circuit 200 is connected to the input terminal of the filter support circuit 300. The output terminal of the filter support circuit 300 is connected to one end of the voltage detection circuit 400 and the first overcurrent detection circuit 500. The input terminal of the voltage detection circuit 400 is connected to the control component 1200; the first output terminal of the first overcurrent detection circuit 500 is connected to one end of the freewheeling circuit 600; the other end of the freewheeling circuit 600 is connected to the first end of the first switching element 700; the control terminal of the first switching element 700 is connected to the output terminal of the drive circuit 800, and the second end of the first switching element 700 is connected to the first end of the second overcurrent detection circuit 900; the input terminal of the drive circuit 800 is connected to the control component 1200, and the third end of the drive circuit 800 is connected to the second output terminal of the fault latch circuit 1100; the second end of the second overcurrent detection circuit 900 is connected to one end of the current detection circuit 1000; the other end of the current detection circuit 1000 is connected to the control component 1200; and the input terminal of the fault latch circuit 1100 is connected to the control component 1200.

[0033] Specifically, the reverse polarity filter circuit 100, as the first-stage protection unit at the power input, connects to external power supply components (such as KL30 (positive terminal of the low-voltage battery) and KL31 (negative terminal of the low-voltage battery)). Its function is to suppress high-frequency noise and surges in the input power supply and automatically block current when the power supply polarity is reversed, preventing damage to subsequent circuits. Its output is connected to the first input of the switching circuit 200, providing clean and safe power to subsequent circuits. The switching circuit 200 is essentially a controlled high-side power switch (usually implemented by a PMOS or integrated high-side driver), and its on / off state is controlled by the first output of the fault latch circuit 1100. When the system is normal, the switching circuit 200 is on, transmitting power to the subsequent stages; once a serious fault occurs (such as a short circuit), the fault latch circuit 1100 immediately pulls down the control signal, forcibly shutting down the switching circuit 200, cutting off the power supply to the entire drive circuit, and achieving first-stage hardware protection. Its output is connected to the filter support circuit 300, providing a stable DC bus for load drive. The filter support circuit 300 can be used to further smooth the power supply voltage, reduce ripple, and provide transient current support. Its output node also serves as the sampling point for the voltage detection circuit 400 and the first overcurrent detection circuit 500. The voltage detection circuit 400 can perform voltage division sampling on the bus voltage after filtering support and send the signal to the control component 1200 (such as a microcontroller) for real-time monitoring of the power supply status, supporting undervoltage and overvoltage judgment, or participating in the feedforward compensation of the current loop. The first overcurrent detection circuit 500 can be used to monitor the high-side current path, mainly for detecting high-side abnormal faults such as short circuits to the power supply at the output terminal. Its detection signal is used to trigger protection logic on the one hand, and connected to the freewheeling circuit 600 on the other hand to ensure that inductive energy can be safely released during fault or normal shutdown. The freewheeling circuit 600 and the first switching device 700 (i.e., the low-side driving MOSFET) together constitute the main drive circuit of the inductive load. When the first switching device 700 is turned off, the back electromotive force generated by the load coil forms a closed loop through the freewheeling path, avoiding high-voltage breakdown of the device. The first switching element 700 serves as the core power switch for low-side driving. Its gate is controlled by the driving circuit 800, its source is grounded, and its drain is connected to one end of the load. Precise control of the inductive load current can be achieved by adjusting its duty cycle using PWM (Pulse Width Modulation) or analog modulation. The driving circuit 800 receives control signals (such as PWM or enable signals) from the control component 1200 and determines whether to actually drive the first switching element 700 based on the state of the second output of the fault latching circuit 1100—even if the control component 1200 issues an on command, the driving circuit remains closed if the fault has been latched, ensuring a "fault priority" principle. The second overcurrent detection circuit 900 is located in the low-side loop and is used to detect low-side faults such as short circuits to ground at the output or overcurrent in the load. Its signal is conditioned and then sent to the current detection circuit 1000.The current detection circuit 1000 differentially amplifies and filters the voltage drop across the low-side sampling resistor, outputting an analog voltage proportional to the load current to the control component 1200. This voltage is used to achieve high-precision closed-loop current control, software overcurrent threshold judgment, or dynamic adjustment. The fault latch circuit 1100, as the core logic unit of the entire protection mechanism (typically based on a D flip-flop or similar latch structure), receives fault enable or reset commands from the control component 1200 and integrates the high-side and low-side overcurrent signals. Upon first detection of a severe fault, it immediately latches the output state, continuously shutting down the (high-side) switching circuit 200 and the (low-side) drive circuit 800 until the system actively resets. This hardware latching mechanism effectively avoids the risk of repeated impacts caused by software delays or misjudgments.

[0034] Therefore, this inductive load drive circuit, through the deep integration of high-side and low-side collaborative detection, dual short-circuit protection, hardware fault latching, and closed-loop current feedback, can ensure reliable operation across the entire temperature range of -40℃ to 125℃ and the entire voltage input range of 9V to 16V. The circuit output drive can provide short-circuit protection for both the power supply and ground. The drive current uses closed-loop control and can be dynamically adjusted according to the application environment. At the same time, this circuit should be independent, not dependent on the functions of other circuits, and its failure should not affect the normal operation of other circuits.

[0035] To facilitate understanding, the following sections will provide a detailed introduction to each functional module in the inductive load drive circuit.

[0036] Optionally, in some embodiments, the filter anti-reverse circuit 100 includes: a second switch Q100, a first resistor R1, first to sixth capacitors C1~C6, a first Zener diode DZ1, and a second Zener diode DZ2. The first terminal of the second switch Q100 is connected to the positive terminal of the power supply component, the second terminal of the second switch Q100 is connected to the switching circuit 200, and the control terminal of the second switch Q100 is connected to one end of the first resistor R1; the other end of the first resistor R1 is connected to the negative terminal of the power supply component; one end of the first capacitor C1 is connected to the connection node between the second switch Q100 and the power supply component, and the other end of the first capacitor C1 is connected to one end of the second capacitor C2; the other end of the second capacitor C2 is connected to the negative terminal of the power supply component; one end of the third capacitor C3 is connected to the connection node between the second switch Q100 and the power supply component. The connection nodes are connected, the other end of the third capacitor C3 is connected to one end of the fourth capacitor C4; the other end of the fourth capacitor C4 is connected to the negative terminal of the power supply component; the cathode of the first Zener diode DZ1 is connected to the connection node between the second switch Q100 and the switching circuit 200, the anode of the first Zener diode DZ1 is connected to the connection node between the second switch Q100 and the first resistor R1 and one end of the fifth capacitor C5; the other end of the fifth capacitor C5 is connected to the negative terminal of the power supply component; the cathode of the second Zener diode DZ2 is connected to the cathode of the first Zener diode DZ1 and the switching circuit 200, the anode of the second Zener diode DZ2 is connected to the negative terminal of the power supply component; one end of the sixth capacitor C6 is connected to the cathode of the second Zener diode DZ2 and the switching circuit 200, and the other end of the sixth capacitor C6 is connected to the negative terminal of the power supply component.

[0037] Specifically, such as Figure 2 As shown, the anti-reverse filtering circuit 100 mainly consists of a second switching element Q100 (typically a P-channel MOSFET), a first resistor R1, first to sixth capacitors C1~C6, a first Zener diode DZ1, and a second Zener diode DZ2. The second switching element Q100 acts as the main anti-reverse control component. During normal power supply, the body diode of the second switching element Q100 conducts first, making the source voltage higher than the gate voltage, forming a negative Vo. GS This causes the second switching element Q100 to be fully turned on, reducing the on-state voltage drop and power consumption; when the power supply is reversed, the body diode is turned off, causing V... GS The positive V is close to 0 or positive. GS The value is approximately equal to the on-state voltage drop of the first Zener diode DZ1, therefore the second switching element Q100 is due to V GS When the voltage is ≥0, it turns off, thus effectively blocking reverse current and achieving non-destructive reverse connection protection. The first Zener diode DZ1 is connected across the second switch Q100, and its main function is to clamp the gate-source voltage V of the second switch Q100. GSThis prevents gate oxide breakdown due to excessive input voltage (such as surges caused by sudden load unloading). Simultaneously, under normal operating conditions, the first Zener diode DZ1 works in conjunction with the body diode of the second switching device Q100 to ensure a suitable bias voltage at the gate, allowing the second switching device Q100 to conduct reliably. The second Zener diode DZ2 can be used for overvoltage clamping protection of the voltage entering subsequent circuits, limiting the bus voltage to the Zener voltage value of the second Zener diode DZ2, further improving the system's surge protection capability. The capacitor network (capacitors C1 to C6) constitutes a multi-stage filtering structure. The low-voltage 12V power is injected through KL30 and KL31 and filtered by capacitors C1, C2, C3, and C4, which can suppress high-frequency conducted interference and electromagnetic noise from the power line. The fifth capacitor C5 is connected in parallel across the first Zener diode DZ1, which can stabilize the gate bias and filter out high-frequency oscillations. The sixth capacitor C6 serves as a local energy storage and high-frequency bypass capacitor, which can provide transient current support for the subsequent switching circuit 200 and further smooth the output voltage.

[0038] Therefore, the filter reverse connection protection circuit 100 not only achieves low-loss and high-reliability reverse connection protection, but also constructs a front-end power conditioning network with strong anti-interference and anti-surge capabilities through multi-stage LC and RC filtering and dual Zener diodes, laying a solid foundation for the stable operation of subsequent drive and protection functions.

[0039] Optionally, in some embodiments, the switching circuit 200 includes: second to fifth resistors R2~R5, a third switch Q103, a third Zener diode DZ3, a seventh capacitor C7, and a fourth switch Q106. One end of the second resistor R2 is connected to the first output terminal of the fault latch circuit 1100, and the other end of the second resistor R2 is connected to the control terminal of the third switch Q103. One end of the third resistor R3 is connected to the connection node between the second resistor R2 and the third switch Q103, and the other end of the third resistor R3 is connected to a ground node. The first end of the third switch Q103 is connected to one end of the fourth resistor R4, and the second end of the third switch Q103 is connected to a ground node. The fourth resistor R4... One end of the fifth resistor R5 is connected to one end of the sixth capacitor C6; the other end of the fifth resistor R5 is connected to one end of the sixth capacitor C6; the anode of the third Zener diode DZ3 is connected to the connection node between the fifth resistor R5 and the fourth resistor R4, and the cathode of the third Zener diode DZ3 is connected to one end of the sixth capacitor C6; one end of the seventh capacitor C7 is connected to the connection node between the fifth resistor R5 and the fourth resistor R4, and the other end of the seventh capacitor C7 is connected to one end of the sixth capacitor C6; the control terminal of the fourth switch Q106 is connected to the connection node between the fifth resistor R5 and the fourth resistor R4, the first end of the fourth switch Q106 is connected to one end of the sixth capacitor C6, and the second end of the fourth switch Q106 is connected to the filter support circuit 300.

[0040] Specifically, such as Figure 2 As shown, the switching circuit 200 mainly consists of the second to fifth resistors R2~R5, the third switching element Q103 (usually an NPN transistor), the third Zener diode DZ3, the seventh capacitor C7, and the fourth switching element Q106 (usually a P-channel MOSFET). The control signal is initially issued by the control component 1200, passes through the first output terminal of the fault latch circuit 1100, and is then output to the base (control terminal) of the second resistor R2 and the third switching element Q103. The third resistor R3 acts as a pull-down resistor to ensure that the third switching element Q103 is reliably turned off when there is no drive signal or the fault latch output is low, thus avoiding false triggering. When the system is normal and fault-free, the fault latch circuit 1100 outputs a high level, causing the third switch Q103 to saturate and conduct. Its collector (first terminal) potential is pulled low, and through the voltage divider network composed of the fourth resistor R4 and the fifth resistor R5, a sufficiently low voltage is formed at the gate of the fourth switch Q106 (i.e., the node between the fourth resistor R4 and the fifth resistor R5). This makes the gate potential of the fourth switch Q106 significantly lower than its source potential, forming a negative Vo. GS This enables the circuit to conduct power, transferring the power from the pre-stage filter anti-reverse circuit (after being filtered by C6) to the filter support circuit 300, thus establishing the power supply path.

[0041] The third Zener diode DZ3 can be powered by the gate-source voltage V used to clamp the fourth switch Q106. GS To prevent the gate drive voltage from being too low (i.e., |V) GS (Excessive stress) causes the PMOS to be subjected to overstress, while ensuring V GS Stable operation within the safe operating range improves device lifespan and reliability. The seventh capacitor C7 is connected in parallel across the third Zener diode DZ3, forming an RC filter network with the fourth resistor R4 and the fifth resistor R5. This network suppresses high-frequency oscillations and noise interference in the gate drive signal, preventing Miller plateau oscillations or malfunctions of the fourth switch Q106 during switching, thus improving switching stability. If a serious fault such as a short circuit or overcurrent occurs, and the control component 1200 is disabled or a fault is detected, the fault latch circuit 1100 can immediately output a low level. At this time, the third switch Q103 is turned off, and the pull-up effect of the fourth resistor R4 causes the gate potential of the fourth switch Q106 to rapidly rise to near the source voltage, resulting in V... GS ≈0, the fourth switch Q106 quickly turns off, completely cutting off the power path to the load, achieving hardware-level rapid protection.

[0042] Therefore, the switching circuit achieves controlled, reliable, and interference-resistant high-side power management through a combination of transistor driving, PMOS high-side switching, voltage regulation clamping, and RC filtering. It is also deeply linked with the fault latching mechanism to ensure that faults can be isolated immediately under any abnormal operating conditions, thus ensuring system safety and fully meeting the functional safety and robustness requirements of automotive-grade drive circuits.

[0043] Optionally, in some embodiments, the filter support circuit 300 includes: a first inductor L100 and eighth to tenth capacitors C8~C10, wherein one end of the first inductor L100 is connected to the second end of the fourth switch Q106, and the other end of the first inductor L100 is connected to the voltage detection circuit 400 and the first overcurrent detection circuit 500 respectively; one end of the eighth capacitor C8 is connected to the connection node between the first inductor L100 and the fourth switch Q106, and the other end of the eighth capacitor C8 is connected to the ground node; one end of the ninth capacitor C9 is connected to the other end of the first inductor L100, and the other end of the ninth capacitor C9 is connected to the ground node; one end of the tenth capacitor C10 is connected to the other end of the first inductor L100, and the other end of the tenth capacitor C10 is connected to the ground node.

[0044] Specifically, such as Figure 2 As shown, the filter support circuit 300 mainly consists of a first inductor L100 and eight to tenth capacitors C8~C10. The first inductor L100 is connected in series in the high-side power supply path, connecting the output terminal of the fourth switch Q106 to the front-end node of the subsequent load. Its main function is to block high-frequency interference from propagating to the load side, and at the same time, it relies on the energy storage characteristics of the inductor to slow down the bus voltage drop when the load current changes suddenly, thereby improving the transient response capability. The eighth capacitor C8 is connected to the input side of the first inductor L100 (close to the fourth switch Q106), which can form a high-frequency bypass on the input side to ground, used to absorb high-frequency ripple generated from the previous power supply or switching action, and prevent it from coupling to the subsequent stage through the inductor. The ninth capacitor C9 and the tenth capacitor C10 are connected in parallel to the output side of the first inductor L100 (i.e., the node after filtering), together forming a large-capacity, low-impedance energy storage node. The ninth capacitor C9 and the tenth capacitor C10 serve to support the voltage and prevent voltage drops. That is, when an inductive load (such as a solenoid valve) suddenly opens or the current rises rapidly, the ninth capacitor C9 and the tenth capacitor C10 can provide local current instantaneously to avoid a sudden drop in bus voltage caused by line impedance, thereby ensuring the sampling accuracy and stability of the voltage detection circuit 400 and the first overcurrent detection circuit 500.

[0045] Overall, the first inductor L100 and the eighth to tenth capacitors C8~C10 constitute a typical π-type filter: the eighth capacitor C8 filters out high-frequency noise, the first inductor L100 blocks noise transmission, and the ninth capacitor C9 and the tenth capacitor C10 further smooth the voltage and provide dynamic support. This multi-stage filtering structure significantly improves power integrity and is especially suitable for complex electromagnetic scenarios in automotive environments with numerous interference sources such as motors and relays.

[0046] Therefore, the filter support circuit not only effectively attenuates power supply noise, but also ensures the stability of the system power supply under all operating conditions (especially large current steps) through the voltage support of the ninth and tenth capacitors, providing a solid power supply foundation for precise current closed-loop control, reliable short-circuit detection and safe drive.

[0047] Optionally, in some embodiments, the voltage detection circuit 400 includes: a sixth resistor R6, a seventh resistor R7, and an eleventh capacitor C11, wherein one end of the sixth resistor R6 is connected to the other end of the first inductor L100, and the other end of the sixth resistor R6 is connected to the control component 1200; one end of the seventh resistor R7 is connected to the connection node between the sixth resistor R6 and the control component 1200, and the other end of the seventh resistor R7 is connected to a ground node; one end of the eleventh capacitor C11 is connected to the connection node between the sixth resistor R6 and the control component 1200, and the other end of the eleventh capacitor C11 is connected to a ground node.

[0048] Specifically, such as Figure 2 As shown, the voltage detection circuit 400 mainly consists of a sixth resistor R6, a seventh resistor R7, and an eleventh capacitor C11. The sixth resistor R6 and the seventh resistor R7 form a high-precision voltage divider network: the bus voltage (from the output of the first inductor L100) is divided in series by the sixth resistor R6 and the seventh resistor R7, resulting in a proportionally reduced sampling voltage across the seventh resistor R7 (i.e., the connection point between the sixth and seventh resistors R6 and R7). This connection point is directly connected to the analog input pin of the control component 1200, enabling indirect monitoring of the original supply voltage. The eleventh capacitor C11 acts as a filter capacitor connected in parallel across the seventh resistor R7, forming an RC low-pass filter. This effectively suppresses high-frequency switching noise, electromagnetic interference, and voltage spikes, ensuring a smooth and stable voltage signal input to the control component and preventing misjudgments or ADC (Analog-to-Digital Converter) sampling fluctuations due to interference.

[0049] It should be noted that the ratio of the sixth resistor R6 to the seventh resistor R7 can be flexibly adjusted according to actual application requirements. For example, within the 9~16V automotive power supply range, if a sampling value of 3.3V (the ADC reference voltage of the MCU) is required at a nominal voltage of 12V, then R6:R7≈2.64:1 can be set. If the system needs to support higher or lower voltage threshold alarms (such as setting the undervoltage lockout point to 8V), only the voltage division ratio needs to be recalculated without modifying the hardware architecture, demonstrating good design versatility and platform adaptability.

[0050] Therefore, the voltage detection circuit 400, through the classic structure of resistor voltage division and capacitor filtering, achieves highly reliable, configurable, and interference-resistant sampling of the bus voltage, providing key state perception basis for the safe operation, dynamic adjustment, and fault response of the entire drive system.

[0051] Optionally, in some embodiments, the first overcurrent detection circuit 500 includes: eighth to twelfth resistors R8~R12, a fifth switch Q109, and a sixth switch Q108, wherein one end of the eighth resistor R8 is connected to the connection node between the first inductor L100 and the sixth resistor R6, and the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9 and the freewheeling circuit 600; the other end of the ninth resistor R9 is connected to the control terminal of the fifth switch Q109; and the first end of the fifth switch Q109 is connected to one end of the eighth resistor R8. The second terminal of the fifth switch Q109 is connected to one end of the tenth resistor R10; the other end of the tenth resistor R10 is connected to one end of the eleventh resistor R11; the other end of the eleventh resistor R11 is connected to the grounding node; the control terminal of the sixth switch Q108 is connected to the connection node between the tenth resistor R10 and the eleventh resistor R11; the first terminal of the sixth switch Q108 is connected to the grounding node; the second terminal of the sixth switch Q108 is connected to one end of the twelfth resistor R12; the other end of the twelfth resistor R12 is connected to the power supply connection node.

[0052] Specifically, such as Figure 2As shown, the first overcurrent detection circuit 500 mainly consists of resistors 8 to 12 (R8~R12), a fifth switch (Q109), and a sixth switch (Q108). Resistor R8 serves as the high-side current sampling resistor, connected in series between the bus after the filter support and the load front end (i.e., the output side of the first inductor L100). During normal operation, the load current flows through resistor R8, generating a small voltage drop across it. When a short circuit occurs at the output to the power supply or a severe overcurrent occurs, the current increases sharply, causing the voltage across resistor R8 to rise rapidly, exceeding 0.7V. This turns on the fifth switch (Q109), allowing current to flow from the high side of resistor R8 through Q109 to the pull-down network composed of resistors R10 and R11. After Q109 turns on, a sufficiently high potential is generated at the node between resistors R10 and R11, causing the sixth switch (Q108) to turn on as well. The collector (second terminal) of the sixth switch Q108 is pulled up to the power supply through the twelfth resistor R12. When Q108 is turned on, it pulls the node level down to near ground potential, thus forming a valid low-level fault signal. This low-level signal can be sent to the fault latch circuit 1100 to trigger its latching action, thereby controlling the fourth switch Q106 in the switching circuit 200 to turn off, completely cutting off the high-side power supply and achieving hardware-level fast protection.

[0053] It should be noted that since the trigger current I=0.7 / R8, the protection threshold can be flexibly set by selecting different values ​​of the eighth resistor R8 (e.g., 7A, 3.5A, etc.) to adapt to inductive loads of different power levels (such as solenoid valves, oil pump motors, etc.), thereby improving the versatility and engineering adaptability of the solution.

[0054] Thus, the first overcurrent detection circuit, through a high-side sampling resistor and a dual-transistor Darlington amplification and level conversion structure, achieves millisecond-level hardware response to high-side overcurrent and short-circuit faults. It also works in conjunction with a fault latching mechanism to ensure that the system can still be safely shut down under extreme fault conditions, fully demonstrating the stringent requirements of automotive-grade drive circuits for functional safety and robustness.

[0055] Optionally, in some embodiments, the freewheeling circuit 600 includes: a freewheeling diode D102 and a second inductor L200, wherein one end of the freewheeling diode D102 is connected to the other end of the eighth resistor R8 and one end of the second inductor L200, and the other end of the freewheeling diode D102 is connected to the other end of the first switch 700 and the second inductor L200.

[0056] Specifically, such as Figure 2As shown, the freewheeling circuit 600 mainly consists of a freewheeling diode D102 (usually a fast recovery diode or a Schottky diode) and a second inductor L200. The second inductor L200 can represent the externally connected inductive load itself (such as an electromagnetic differential lock coil, oil pump motor winding, etc.), while the freewheeling diode D102 is connected across the load, forming a typical freewheeling loop. When the first switch 700 is turned on, current flows from the high-side power supply (through the filter support circuit 300 and the eighth resistor R8) into the Drive out terminal, through the external inductive load, the second inductor L200, and then through the Drive in terminal to the drain of the first switch 700, finally grounding through the source, completing normal driving. Once the control signal turns off the first switch 700, because the inductor current cannot change abruptly, the second inductor L200 will immediately induce a high voltage with reversed polarity (negative at the top, positive at the bottom), attempting to maintain the original current direction. At this time, the freewheeling diode D102 is forward biased and conducts, forming a closed freewheeling circuit (i.e., Driveout-second inductor L200-Drive in-freewheeling diode D102-Drive out).

[0057] In the aforementioned freewheeling circuit, the energy stored in the second inductor L200 is released cyclically as current through the freewheeling diode D102, and is gradually consumed by the line resistance and diode voltage drop, resulting in an exponential decay of the current. This process effectively clamps the voltage at the Drive-in node, preventing the MOSFET drain from experiencing hundreds of volts of induced high voltage, thereby protecting the first switching device 700 and other sensitive circuits.

[0058] Therefore, the entire freewheeling mechanism requires no software intervention and is fully implemented automatically by the circuit topology. It has the advantages of fast response, high reliability and simple structure, and is an indispensable safety guarantee design in inductive load driving.

[0059] Optionally, in some embodiments, the second overcurrent detection circuit 900 includes: thirteenth to fifteenth resistors R13~R15 and a seventh switch Q107, wherein one end of the thirteenth resistor R13 is connected to the second end of the first switch 700, and the other end of the thirteenth resistor R13 is connected to a ground node; one end of the fourteenth resistor R14 is connected to one end of the thirteenth resistor R13, and the other end of the fourteenth resistor R14 is connected to the control terminal of the seventh switch Q107; the first end of the seventh switch Q107 is connected to the ground node, and the second end of the seventh switch Q107 is connected to one end of the twelfth resistor R12; one end of the fifteenth resistor R15 is connected to the connection node between the fourteenth resistor R14 and the seventh switch Q107, and the other end of the fifteenth resistor R15 is connected to the ground node.

[0060] Specifically, such as Figure 2As shown, the second overcurrent detection circuit 900 mainly consists of resistors R13 to R15 (13th to 15th) and the seventh switch Q107 (NPN transistor). Resistor R13 serves as the low-side current sampling resistor. During normal system operation, the load current flows through resistor R13, generating a voltage drop proportional to the current across it. When the load current abnormally increases (e.g., due to a short circuit to ground at the output Drive in or motor stall), the voltage drop across resistor R13 increases accordingly. When the voltage across resistor R13 exceeds 0.7V, the seventh switch Q107 conducts. After Q107 conducts, its collector (second terminal) is pulled low to near ground potential. This collector is connected to pin A of the D flip-flop in the fault latch circuit 1100 (i.e., the reset or set control terminal), pulling pin A low and causing QA to output high. This action immediately latches the fault state.

[0061] Understandably, fault latching can produce a dual protection effect: on the one hand, the PWM drive signal is shielded, that is, no matter what PWM command the control component 1200 issues, the drive circuit 800 cannot activate the first switch 700, thus achieving "PWM invalid"; on the other hand, the Q output of the D flip-flop goes low, which is fed back to the switch circuit 200, causing the fourth switch Q106 to be turned off, completely cutting off the power supply to the entire drive circuit.

[0062] In addition, since the fourteenth resistor R14 is used to couple the sampling voltage of the high end of the thirteenth resistor R13 to the base of the seventh switch Q107, and the fifteenth resistor R15 is used as a pull-down resistor, it can ensure that the base of the seventh switch Q107 is at a low level when there is no overcurrent, avoiding false triggering and improving anti-interference capability.

[0063] It should be noted that the overcurrent threshold can be flexibly set by adjusting the resistance value of the thirteenth resistor R13.

[0064] Thus, the second overcurrent detection circuit, through a mechanism of low-side sampling, transistor comparison, and hardware latch linkage, achieves millisecond-level response and irreversible protection against ground short circuits and overload faults. Together with the first overcurrent detection circuit (high-side protection), it forms a complete bidirectional short-circuit protection system, significantly improving the functional safety level of the vehicle drive system.

[0065] Optionally, in some embodiments, the current detection circuit 1000 includes: sixteenth to nineteenth resistors R16-R19, twelfth to fourteenth capacitors C12-C14, and a comparison unit U101. One end of the sixteenth resistor R16 is connected to a ground node, and the other end is connected to the first input terminal of the comparison unit U101. One end of the seventeenth resistor R17 is connected to a ground node, and the other end is connected to the second input terminal of the comparison unit U101. One end of the eighteenth resistor R18 is connected to the second input terminal of the comparison unit U101, and the other end is connected to the output terminal of the comparison unit U101. One end of the twelfth capacitor C12 is connected to the second input terminal of the comparison unit U101. The 12th capacitor C12 is connected to the output terminal of the comparator U101, and the other end of the 13th capacitor C13 is connected to the first input terminal of the comparator U101. The other end of the 13th capacitor C13 is connected to the grounding node. The 19th resistor R19 is connected to the first input terminal of the comparator U101, and the other end of the 19th resistor R19 is connected to the grounding node. The 14th capacitor C14 is connected to the grounding node, and the other end of the 14th capacitor C14 is connected to the output terminal of the comparator U101. The power supply terminal of the comparator U101 is connected to the power supply access node, the ground terminal of the comparator U101 is connected to the grounding node, and the output terminal of the comparator U101 is connected to the power supply access node and the control component 1200, respectively.

[0066] Specifically, such as Figure 2 As shown, the current detection circuit 1000 mainly consists of resistors R16~R19 (sixteenth to nineteenth), capacitors C12~C14 (twelfth to fourteenth), and comparator unit U101. The comparator unit U101 is actually an operational amplifier, used as a precision differential amplifier or subtractor. Together with resistors R16~R19 (sixteenth to nineteenth) and capacitors C12~C14 (twelfth to fourteenth), it forms a typical instrument-grade subtractor structure. Its core function is to differentially amplify and filter the small voltage difference across the low-side sampling resistor (i.e., resistor R13 in the second overcurrent detection circuit), and output an analog signal that is linearly proportional to the load current for the control component 1200 to perform ADC sampling, closed-loop regulation, or software-level overcurrent judgment.

[0067] The thirteenth resistor R13 is connected in series between the source of the first switching element 700 and the ground node. When the load current I... load When the current flows through, its high-side potential (closest to the source) is V+ = I. load ×R13, low-end ground V =0. To suppress common-mode noise and improve measurement accuracy, the circuit does not directly ground the reference. Instead, the non-inverting input (first input) of the comparator unit U101 is connected to a node near the high end of the thirteenth resistor R13 via the sixteenth resistor R16 and the nineteenth resistor R19 (the actual grounding point is introduced through the sixteenth resistor R16 for impedance matching and biasing). The seventeenth resistor R17 and the eighteenth resistor R18 connect the inverting input (second input) to system ground or the reference point, thus constructing a true differential input structure. The thirteenth capacitor C13 and the nineteenth resistor R19, and the twelfth capacitor C12 and the eighteenth resistor R18 respectively form RC filter networks for the input and feedback paths, effectively suppressing high-frequency switching noise, PWM harmonics, and electromagnetic interference. The fourteenth capacitor C14 serves as an output bypass capacitor, further smoothing the output signal and ensuring that the voltage sent to the MCU is stable and reliable. Finally, the amplified current signal is sent from the output of the comparator unit U101 to the ADC pin of the control component 1200 for: real-time monitoring of the load current; constructing a current closed-loop control loop (such as constant current drive); and software-assisted overcurrent protection (forming dual redundancy with the hardware second overcurrent detection circuit 900).

[0068] Thus, the current detection circuit, through a precision subtractor architecture, achieves high common-mode rejection ratio, low noise, and adjustable gain amplification of the low-side sampling voltage, providing accurate and reliable current feedback information for the system.

[0069] Furthermore, the drive circuit 800 can control the on / off state of the first switching element 700. For example... Figure 2 As shown, the circuit mainly consists of multiple resistors and multiple switches. During normal system operation (no faults, normal power supply), when the control component 1200 outputs a high-level PWM signal, the eighth switch Q102 (usually an NPN transistor) turns on first, pulling the base of the ninth switch Q104 (a PNP transistor) low. At this time, the emitter of the ninth switch Q104 is connected to a high potential (from the power supply or drive rail), while the base is low. Therefore, the ninth switch Q104 turns on, injecting current into the gate of the first switch 700, rapidly raising its gate-source voltage V. GS When the threshold value is above the threshold, the first switch 700 is quickly turned on. When the PWM signal output by the control component 1200 is low, the eighth switch Q102 is turned off, and the ninth switch Q104 is turned off, stopping the charging of the gate of the first switch 700. At this time, the tenth switch Q105 is designed to be turned on (its base obtains sufficient voltage through a pull-up or bias network), forming a low-impedance discharge path: the gate charge of the first switch 700 is quickly discharged to ground through the tenth switch Q105, accelerating V GS The descent causes the first switching element 700 to turn off rapidly.

[0070] When the drive is disabled due to system failure or abnormality, the control terminal of the eleventh switch Q101 receives the QA output signal (usually the latched state of a D flip-flop) from the fault latch circuit. Only when the system is fault-free and power is established normally, the QA output is low, the eleventh switch Q101 is not turned on, and the PWM signal is allowed to be transmitted to subsequent drive stages (eighth switch Q102, etc.). In the event of a serious fault such as overcurrent or short circuit, the fault latch circuit immediately sets QA high, the eleventh switch Q101 is turned on, and the enable path of the entire drive chain is cut off. Even if the control component is still sending PWM, it cannot drive the eighth switch Q102, thus ensuring that the first switch 700 is always in the off state.

[0071] Therefore, this drive circuit not only possesses rapid turn-on and turn-off capabilities, low switching losses, and strong anti-interference capabilities, but also establishes a dual verification mechanism for software instructions and hardware safety status through the linkage of the tenth switching element and the fault latch signal. PWM instructions are only allowed to execute under the dual conditions of normal power supply and no latch fault, fundamentally eliminating the risk of operation with faults and greatly improving the reliability and safety of the inductive load drive system.

[0072] Optionally, such as Figure 2 As shown, the fault latch circuit 1100 can use a single-path positive edge-triggered D-type flip-flop as the core logic unit for fault latching and state control. The flip-flop has two low-level active asynchronous control terminals: asynchronous set PRE (Preset) and asynchronous reset CLR (Clear). When PRE=0 (low level), regardless of the state of the clock CLK, data input D, or CLR, the output Q is forced to a high level (Q=1); when CLR=0 (low level), similarly, ignoring other inputs, the output Q is forced to a low level (Q=0). For example, when the first overcurrent detection circuit 500 or the second overcurrent detection circuit 900 detects a short-circuit fault, it will immediately pull the CLR pin low, instantly setting the Q output to a low level, thereby turning off the high-side fourth switch Q106 and disabling the drive circuit 800, achieving millisecond-level hardware protection without waiting for the clock edge or software intervention.

[0073] When PRE=1 and CLR=1 (i.e., both are in an inactive high-level state), the flip-flop enters the normal synchronous working mode. At this time, when the rising edge (positive edge) of the clock signal CLK arrives, if the data input terminal D meets the timing requirements of setup time and hold time, the logic level of the D terminal will be reliably latched to the output terminal Q. In this embodiment of the present invention, the D input is usually connected to the enable or reset instruction (such as enable drive or manually clear fault) from the control component 1200. CLK can be provided by the system clock or a dedicated control pulse to update the drive state under safe conditions.

[0074] In this embodiment of the invention, once an overcurrent or short circuit occurs, the first overcurrent detection circuit 500 and the second overcurrent detection circuit 900 pull the CLR low, and the Q output immediately goes low and remains low (Q remains low even if the fault signal disappears), thus achieving a "fault-locked-once-occurrence" safety mechanism. After confirming the fault is cleared, the control component 1200 will raise the CLR, thereby setting Q high, restoring drive enable, and completing a system restart. Since the output state is only updated at the clock edge (in normal mode), it effectively avoids false state flips caused by noise or glitches, improving system robustness. The truth table of the positive edge-triggered D-type flip-flop can be as follows: Figure 3 As shown.

[0075] It should be noted that during the initial power-on or standby state of the system, the fourth switch 106 is not yet turned on. Under normal circumstances, the Drive out node should be in a floating or low-level state. However, if the external wiring harness is incorrectly connected or a load failure occurs, causing Drive out to be directly shorted to the vehicle power supply (such as KL30, 12V / 24V), this node will be forcibly pulled to a high potential. At this time, the voltage detection circuit 400 can continuously monitor the bus voltage node after the filter support (i.e., the output terminal of the first inductor L100, which is connected to Drive out through the eighth resistor R8). Although the fourth switch Q106 is turned off, because Drive out is pulled high by the external power supply, this voltage can still be transmitted to the sampling point through the eighth resistor R8, causing the voltage detection circuit to collect an abnormally higher voltage value than expected (e.g., close to 12V, while it should be close to 0V in normal standby). The control component 1200 can read the voltage through the ADC. If it is determined that the voltage is significantly higher than the set threshold (e.g., >2V), it can be determined that "Drive out short circuit to power supply". The control component 1200 will then disable the output of the PWM drive signal and report a fault code to prevent subsequent accidental opening of the high-side switch, which could lead to large current backflow or device damage.

[0076] When the fourth switch Q106 is turned on and the system is operating normally, if the Drive-in node is directly short-circuited to ground due to internal load breakdown, wiring harness damage, or other reasons, the load current will increase sharply (theoretically limited only by the line impedance), easily burning out the MOSFET or PCB (Printed Circuit Board) traces. To address this, this embodiment of the invention uses a pure hardware overcurrent detection circuit (i.e., the first overcurrent detection circuit 500) for millisecond-level response: current flows through the high-side sampling resistor (i.e., the eighth resistor R8), generating a voltage drop V across it. R8 =I×R8, when a short circuit occurs, I rises rapidly, causing V to... R8>0.7V (silicon transistor turn-on threshold); at this time, the fifth switch Q109 turns on, which in turn drives the sixth switch Q108 to turn on; after the sixth switch Q108 turns on, it pulls its collector (connected to pin A of the D flip-flop in the fault latch circuit 1100) low to near ground level; the D flip-flop detects that pin A is low and immediately sets the output Q to low level (asynchronous reset takes priority); this low-level signal is fed back to the switching circuit 200, forcibly turning off the fourth switch Q106 and completely cutting off the power supply; at the same time, this state is latched, and even if the short circuit is removed, the system will not restart automatically and the microcontroller needs to actively reset.

[0077] In summary, according to the inductive load drive circuit of this utility model embodiment, the power supply is filtered and reverse-biased before being controlled by a switching circuit for on / off switching. The load current is regulated by a first switching element and detected by dual-path overcurrent detection. A freewheeling circuit releases the energy when the inductive load is turned off. Voltage and current detection signals are fed back to the control component to achieve closed-loop control. A fault latching circuit locks the output in case of abnormality to ensure safety. This circuit, based on a low-side drive architecture, integrates a high-side power switch, high / low-side overcurrent detection, freewheeling path, current closed-loop control, and fault latching mechanism, achieving dual protection against power supply and ground short circuits, effectively improving the reliability and safety of the circuit.

[0078] This utility model embodiment also provides a vehicle, the vehicle including... Figure 1 The inductive load drive circuit of the embodiment.

[0079] The vehicle according to this utility model embodiment achieves dual protection against power supply and ground short circuits by integrating an inductive load drive circuit with a high-side power switch, high / low-side overcurrent detection, freewheeling path, current closed-loop control and fault latching mechanism, effectively improving the reliability and safety of the circuit.

[0080] Through the above description of the embodiments, those skilled in the art will understand that, for the sake of convenience and brevity, only the division of the above functional modules is used as an example. In actual applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the device can be divided into different functional modules to complete all or part of the functions described above.

[0081] In the embodiments provided by this utility model, it should be understood that the disclosed apparatus and method can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative. For instance, the division of modules or units is only a logical functional division, and in actual implementation, there may be other division methods. For example, multiple units or components may be combined or integrated into another device, or some features may be ignored or not executed. Furthermore, the coupling or direct coupling or communication connection shown or discussed may be through some interfaces; the indirect coupling or communication connection between devices or units may be electrical, mechanical, or other forms.

[0082] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this utility model should be included within the protection scope of this utility model. Therefore, the protection scope of this utility model should be determined by the scope of the claims.

Claims

1. An inductive load drive circuit, characterized in that, include: The circuit includes a filter anti-reverse circuit, a switching circuit, a filter support circuit, a voltage detection circuit, a first overcurrent detection circuit, a freewheeling circuit, a first switching element, a drive circuit, a second overcurrent detection circuit, a current detection circuit, a fault latching circuit, and a control component. The input terminal of the filter anti-reverse circuit is connected to the power supply component, and the output terminal of the filter anti-reverse circuit is connected to the first input terminal of the switching circuit. The second input terminal of the switching circuit is connected to the first output terminal of the fault latch circuit, and the output terminal of the switching circuit is connected to the input terminal of the filter support circuit. The output terminal of the filter support circuit is connected to one end of the voltage detection circuit and the input terminal of the first overcurrent detection circuit, respectively. The other end of the voltage detection circuit is connected to the control component; The first output terminal of the first overcurrent detection circuit is connected to one end of the freewheeling circuit; The other end of the freewheeling circuit is connected to the first end of the first switching element; The control terminal of the first switch is connected to the output terminal of the drive circuit, and the second terminal of the first switch is connected to the first terminal of the second overcurrent detection circuit. The input terminal of the drive circuit is connected to the control component, and the third terminal of the drive circuit is connected to the second output terminal of the fault latch circuit. The second terminal of the second overcurrent detection circuit is connected to one terminal of the current detection circuit; The other end of the current detection circuit is connected to the control component; The input terminal of the fault latch circuit is connected to the control component.

2. The inductive load drive circuit according to claim 1, characterized in that, The filtering and anti-reverse circuit includes: a second switch, a first resistor, first to sixth capacitors, a first Zener diode, and a second Zener diode, wherein... The first end of the second switch is connected to the positive terminal of the power supply component, the second end of the second switch is connected to the switching circuit, and the control terminal of the second switch is connected to one end of the first resistor. The other end of the first resistor is connected to the negative terminal of the power supply component; One end of the first capacitor is connected to the connection node between the second switch and the power supply component, and the other end of the first capacitor is connected to one end of the second capacitor. The other end of the second capacitor is connected to the negative terminal of the power supply component; One end of the third capacitor is connected to the connection node between the second switch and the power supply component, and the other end of the third capacitor is connected to one end of the fourth capacitor. The other end of the fourth capacitor is connected to the negative terminal of the power supply component; The cathode of the first Zener diode is connected to the connection node between the second switch and the switching circuit, and the anode of the first Zener diode is connected to the connection node between the second switch and the first resistor and one end of the fifth capacitor. The other end of the fifth capacitor is connected to the negative terminal of the power supply component; The cathode of the second Zener diode is connected to the cathode of the first Zener diode and the switching circuit, respectively, and the anode of the second Zener diode is connected to the negative terminal of the power supply component. One end of the sixth capacitor is connected to the cathode of the second Zener diode and the switching circuit, and the other end of the sixth capacitor is connected to the negative terminal of the power supply component.

3. The inductive load drive circuit according to claim 2, characterized in that, The switching circuit includes: second to fifth resistors, a third switching element, a third Zener diode, a seventh capacitor, and a fourth switching element, wherein, One end of the second resistor is connected to the first output terminal of the fault latch circuit, and the other end of the second resistor is connected to the control terminal of the third switch. One end of the third resistor is connected to the connection node between the second resistor and the third switch, and the other end of the third resistor is connected to the ground node; The first end of the third switch is connected to one end of the fourth resistor, and the second end of the third switch is connected to the grounding node; One end of the fourth resistor is connected to one end of the fifth resistor; The other end of the fifth resistor is connected to one end of the sixth capacitor; The anode of the third Zener diode is connected to the connection node between the fifth resistor and the fourth resistor, and the cathode of the third Zener diode is connected to one end of the sixth capacitor. One end of the seventh capacitor is connected to the connection node between the fifth resistor and the fourth resistor, and the other end of the seventh capacitor is connected to one end of the sixth capacitor; The control terminal of the fourth switch is connected to the connection node between the fifth resistor and the fourth resistor, the first terminal of the fourth switch is connected to one end of the sixth capacitor, and the second terminal of the fourth switch is connected to the filter support circuit.

4. The inductive load drive circuit according to claim 3, characterized in that, The filter support circuit includes: a first inductor and eighth to tenth capacitors, wherein, One end of the first inductor is connected to the second end of the fourth switching device, and the other end of the first inductor is connected to the voltage detection circuit and the first overcurrent detection circuit, respectively. One end of the eighth capacitor is connected to the connection node between the first inductor and the fourth switch, and the other end of the eighth capacitor is connected to the ground node. One end of the ninth capacitor is connected to the other end of the first inductor, and the other end of the ninth capacitor is connected to the grounding node. One end of the tenth capacitor is connected to the other end of the first inductor, and the other end of the tenth capacitor is connected to the grounding node.

5. The inductive load drive circuit according to claim 4, characterized in that, The voltage detection circuit includes: a sixth resistor, a seventh resistor, and an eleventh capacitor, wherein, One end of the sixth resistor is connected to the other end of the first inductor, and the other end of the sixth resistor is connected to the control component; One end of the seventh resistor is connected to the connection node between the sixth resistor and the control component, and the other end of the seventh resistor is connected to the grounding node; One end of the eleventh capacitor is connected to the connection node between the sixth resistor and the control component, and the other end of the eleventh capacitor is connected to the grounding node.

6. The inductive load drive circuit according to claim 5, characterized in that, The first overcurrent detection circuit includes: resistors eight to twelfth, a fifth switch, and a sixth switch, wherein, One end of the eighth resistor is connected to the connection node between the first inductor and the sixth resistor, and the other end of the eighth resistor is connected to one end of the ninth resistor and the freewheeling circuit. The other end of the ninth resistor is connected to the control terminal of the fifth switch. The first end of the fifth switch is connected to one end of the eighth resistor, and the second end of the fifth switch is connected to one end of the tenth resistor; The other end of the tenth resistor is connected to one end of the eleventh resistor; The other end of the eleventh resistor is connected to the grounding node; The control terminal of the sixth switch is connected to the connection node between the tenth resistor and the eleventh resistor, the first terminal of the sixth switch is connected to the grounding node, and the second terminal of the sixth switch is connected to one end of the twelfth resistor. The other end of the twelfth resistor is connected to the power supply access node.

7. The inductive load drive circuit according to claim 6, characterized in that, The freewheeling circuit includes: a freewheeling diode and a second inductor, wherein, One end of the freewheeling diode is connected to the other end of the eighth resistor and one end of the second inductor, respectively, and the other end of the freewheeling diode is connected to the other end of the first switch and the other end of the second inductor, respectively.

8. The inductive load drive circuit according to claim 7, characterized in that, The second overcurrent detection circuit includes: resistors thirteenth to fifteenth, and a seventh switch, wherein, One end of the thirteenth resistor is connected to the second end of the first switching element, and the other end of the thirteenth resistor is connected to the grounding node; One end of the fourteenth resistor is connected to one end of the thirteenth resistor, and the other end of the fourteenth resistor is connected to the control terminal of the seventh switch. The first end of the seventh switch is connected to the grounding node, and the second end of the seventh switch is connected to one end of the twelfth resistor; One end of the fifteenth resistor is connected to the connection node between the fourteenth resistor and the seventh switch, and the other end of the fifteenth resistor is connected to the grounding node.

9. The inductive load drive circuit according to claim 8, characterized in that, The current detection circuit includes: resistors sixteenth to nineteenth, capacitors twelfth to fourteenth, and a comparison unit, wherein... One end of the sixteenth resistor is connected to the grounding node, and the other end of the sixteenth resistor is connected to the first input terminal of the comparison unit; One end of the seventeenth resistor is connected to the grounding node, and the other end of the seventeenth resistor is connected to the second input terminal of the comparison unit; One end of the eighteenth resistor is connected to the second input terminal of the comparator unit, and the other end of the eighteenth resistor is connected to the output terminal of the comparator unit. One end of the twelfth capacitor is connected to the second input terminal of the comparator unit, and the other end of the twelfth capacitor is connected to the output terminal of the comparator unit. One end of the thirteenth capacitor is connected to the first input terminal of the comparison unit, and the other end of the thirteenth capacitor is connected to the ground node. One end of the nineteenth resistor is connected to the first input terminal of the comparison unit, and the other end of the nineteenth resistor is connected to the ground node; One end of the fourteenth capacitor is connected to the grounding node, and the other end of the fourteenth capacitor is connected to the output terminal of the comparison unit. The power supply terminal of the comparison unit is connected to the power access node, the ground terminal of the comparison unit is connected to the ground node, and the output terminal of the comparison unit is connected to the power access node and the control component respectively.

10. A vehicle, characterized in that, include: The inductive load drive circuit as described in any one of claims 1-9.

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