Engine load dump high voltage surge suppression circuit

Abstract

The present application relates to an engine load dump high-voltage surge suppression circuit, which includes a detection module, a control module, and a discharge module; the detection module responds to a first detection voltage and transmits the first detection voltage to the input end of the control module, where the first detection voltage is a voltage greater than a preset threshold voltage; the input end of the control module responds to the first detection voltage, and the output end of the control module outputs a first signal; the first input end of the discharge module responds to the first signal and is turned on, so that the second end of the discharge module is connected to the positive pole of the battery, and the third end of the discharge module is connected to the negative pole of the battery, forming a parallel circuit between the discharge module and the battery, so that the discharge module serves as a load for the external circuit to discharge the external circuit, which is conducive to eliminating the load dump condition, effectively suppressing the high-voltage surge breakdown of circuit components due to current mutation in the external circuit of the engine, and protecting the battery management system.

Description

Technical Field

[0001] The present application relates to the field of automotive electronics technology, and in particular to an engine load dump high-voltage surge suppression circuit. Background Art

[0002] With the widespread adoption of new energy vehicles and hybrid electric vehicles, engines serve as auxiliary power sources or power generation units, often supplying power to battery packs via generators. However, during vehicle operation, the engine may suddenly lose load (also known as "load dump"). During this situation, the energy originally supplied to the load cannot be consumed in a timely manner, which can easily trigger transient high-voltage surges in the circuit, causing the voltage to rise too quickly, which in turn can impact the battery pack and control circuits, posing a significant safety hazard.

[0003] Existing load-dump protection schemes mostly rely on quickly disconnecting the main charging path, attempting to prevent abnormal voltage increases by cutting off energy input. However, this approach has two obvious problems: first, the disconnection action often lags behind the voltage rise, making it difficult to suppress surges in a timely manner; second, there is a lack of an effective energy dissipation path, and high-voltage energy has nowhere to be released, which can easily lead to risks such as MOS tube breakdown, controller reset, and even vehicle power loss.

[0004] In addition, although some battery management systems (BMS) have overvoltage detection functions, they are usually only used for abnormal alarms or simple cut-offs. They lack sequential control mechanisms and energy discharge paths, and cannot meet the requirements for system response speed and safety in engine load-off scenarios.

[0005] Therefore, there is an urgent need for a load dump protection circuit that can guide the safe discharge of excess energy when the engine generates high voltage due to a sudden change in current, effectively suppress high-voltage surges, and thus effectively protect the battery pack and the entire power system. Summary of the Invention

[0006] The present application provides an engine load dump high-voltage surge suppression circuit to solve the problem in the prior art that when the engine generates high voltage breakdown of circuit components due to sudden current changes, the high-voltage surge cannot be effectively suppressed.

[0007] In a first aspect, the present application provides an engine load dump high-voltage surge suppression circuit, the engine load dump high-voltage surge suppression circuit comprising a detection module, a control module, and a discharge module;

[0008] The input end of the detection module is connected to the negative electrode of the battery, and the output end is connected to the input end of the control module;

[0009] The first output terminal of the control module is connected to the first input terminal of the discharge module;

[0010] The output end of the discharge module is connected to the external circuit of the engine;

[0011] The detection module transmits the first detection voltage to the input terminal of the control module in response to the first detection voltage, wherein the first detection voltage is a voltage greater than a preset threshold voltage;

[0012] The input terminal of the control module responds to the first detection voltage, and the output terminal of the control module outputs a first signal;

[0013] The first input end of the discharge module responds to the first signal and is turned on, so that the second end of the discharge module is connected to the positive electrode of the battery, and the third end of the discharge module is connected to the negative electrode of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit to discharge the external circuit.

[0014] Optionally, the detection module includes a sampling resistor, and the detection module includes an AFE acquisition chip;

[0015] The input end of the sampling resistor is connected to the negative electrode of the battery, and the output end is connected to the input end of the AFE acquisition chip;

[0016] The input end of the sampling resistor converts the detection current into a detection voltage in response to the detection current of the negative electrode of the battery, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module;

[0017] When the detection voltage is greater than or equal to a preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

[0018] Optionally, the control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit and a discharge resistor, and the discharge switch unit includes a discharge switch unit first end, a discharge switch unit control end and a discharge switch unit second end;

[0019] The input end of the discharge signal unit is connected to the first output end of the control module, and the output end is connected to the negative electrode of the battery;

[0020] The first end of the discharge switch unit is connected to the first end of the discharge resistor, the control end of the discharge switch unit is connected to the positive electrode of the battery, and the second end of the discharge switch unit is connected to the output end of the discharge signal unit;

[0021] The second end of the discharge resistor is connected to the first end of the discharge switch unit;

[0022] The control end of the discharge switch unit turns on the discharge switch unit in response to the voltage of the positive electrode of the battery, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0023] Optionally, the discharge signal unit includes a first resistor and an optical coupler;

[0024] The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optical coupler;

[0025] The output end of the optical coupler is connected to the negative electrode of the battery and the second end of the discharge switch unit;

[0026] The control end of the discharge switch unit is turned on in response to a high voltage level at the positive electrode of the battery, and the first end of the discharge switch unit is connected to the second end of the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0027] Optionally, the discharge module further includes a second resistor, a first NPN transistor, a third resistor, a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor.

[0028] Optionally, the input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN transistor;

[0029] The emitter of the first NPN transistor is connected to the input end of the third resistor;

[0030] The output end of the third resistor is connected to the emitter of the first PNP transistor;

[0031] The collector of the first PNP transistor is connected to the anode of the first crystal diode;

[0032] The cathode of the first crystal diode is connected to the anode of the second crystal diode;

[0033] The cathode of the second crystal diode is connected to the input end of the fourth resistor;

[0034] The output end of the fourth resistor is connected to the control end of the discharge switch unit.

[0035] Optionally, the control module further includes a charging switch unit, and when the discharge switch unit is turned on and the discharge resistor is connected in parallel with the battery, the second output terminal of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit;

[0036] The charging switch unit is turned off in response to the second signal to disconnect the external circuit from the battery.

[0037] Optionally, the charging switch unit includes a charging switch unit first end, a charging switch unit control end, and a charging switch unit second end;

[0038] The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control end of the charging switch unit is connected to the second output end of the MCU control chip;

[0039] The charging switch unit control end disconnects the first end of the charging switch unit from the second end of the charging switch unit in response to the second signal, thereby disconnecting the negative electrode of the external circuit from the negative electrode of the battery, and causing the external circuit to stop charging the battery.

[0040] Optionally, the control module further includes a fifth resistor, a second NPN transistor, a sixth resistor, a second PNP transistor, a third crystal diode, a fourth crystal diode and a seventh resistor.

[0041] Optionally, the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN transistor;

[0042] The collector of the second NPN transistor is connected to the input end of the sixth resistor;

[0043] The output end of the sixth resistor is connected to the base of the second PNP transistor;

[0044] The collector of the second PNP transistor is connected to the anode of the third crystal diode;

[0045] The cathode of the third crystal diode is connected to the anode of the fourth crystal diode;

[0046] The cathode of the fourth crystal diode is connected to the input end of the seventh resistor;

[0047] The output end of the seventh resistor is connected to the control end of the charging switch unit.

[0048] The present application relates to an engine load dump high-voltage surge suppression circuit, and the load dump protection circuit includes a detection module, a control module, and a discharge module; the detection module responds to a first detection voltage and transmits the first detection voltage to the input end of the control module, and the first detection voltage is a voltage greater than a preset threshold voltage; the input end of the control module responds to the first detection voltage, and the output end of the control module outputs a first signal; the first input end of the discharge module responds to the first signal and is turned on, so that the second end of the discharge module is connected to the positive pole of the battery, and the third end of the discharge module is connected to the negative pole of the battery, forming a parallel circuit between the discharge module and the battery, so that the discharge module serves as a load of the external circuit to discharge the external circuit, which is conducive to eliminating the load dump condition, effectively suppressing the high-voltage surge breakdown of circuit components due to current mutation in the external circuit of the engine, and protecting the battery management system. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0050] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0051] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0052] Figure 1 This is a schematic diagram of the structure of the engine load dump high-voltage surge suppression circuit provided by this application;

[0053] Figure 2 This is a circuit diagram of the engine load dump high-voltage surge suppression circuit provided in this application. DETAILED DESCRIPTION

[0054] To make the purpose, technical solutions, and advantages of the embodiments of this application more clear, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the drawings in the embodiments of this application. Obviously, the described embodiments are part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0055] The disclosure below provides many different embodiments or examples for implementing different configurations of the present invention. To simplify the disclosure of the present invention, the components and configurations of specific examples are described below. Of course, these are merely examples and are not intended to limit the present invention. In addition, the present invention may repeat reference numerals and / or letters in different examples. Such repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or configurations discussed.

[0056] In order to solve the problems in the prior art, the present application provides an engine load dump high voltage surge suppression circuit. Figure 1 This is a structural diagram of the engine load dump high-voltage surge suppression circuit provided by this application, which includes a detection module, a control module, and a discharge module;

[0057] The input end of the detection module is connected to the negative electrode of the battery, and the output end is connected to the input end of the control module;

[0058] The first output terminal of the control module is connected to the first input terminal of the discharge module;

[0059] The output end of the discharge module is connected to the external circuit of the engine;

[0060] The detection module transmits the first detection voltage to the input terminal of the control module in response to the first detection voltage, wherein the first detection voltage is a voltage greater than a preset threshold voltage;

[0061] The input terminal of the control module responds to the first detection voltage, and the output terminal of the control module outputs a first signal;

[0062] The first input end of the discharge module responds to the first signal and is turned on, so that the second end of the discharge module is connected to the positive electrode of the battery, and the third end of the discharge module is connected to the negative electrode of the battery, forming a parallel circuit of the discharge module and the battery, so that the discharge module serves as a load of the external circuit to discharge the external circuit.

[0063] Among them, the input end of the detection module is connected to the negative pole of the battery, and the output end is connected to the input end of the control module; the first output end of the control module is connected to the first input end of the discharge module; the output end of the discharge module is connected to the external circuit of the engine.

[0064] In this embodiment of the present application, the detection module continuously monitors key voltage parameters of the battery system during normal system operation. When the detection module detects that the voltage of one or more battery cells reaches or exceeds a preset threshold voltage (i.e., a first detection voltage), it outputs this first detection voltage as a voltage signal to the input of the control module. This first detection voltage is a voltage value above the system's predefined safety range and typically corresponds to a high-voltage surge generated when the engine suddenly loses load.

[0065] After receiving the first detection voltage, the control module determines that the current system is in a load dump risk state, and its output terminal immediately outputs a first control signal to the discharge module to instruct it to perform a protection action.

[0066] In response to the first control signal, the first input terminal of the discharge module enters a conductive state, thereby establishing a new energy discharge path. Specifically, the second terminal of the discharge module is connected to the positive terminal of the battery, and the third terminal is connected to the negative terminal of the battery, forming a current loop in parallel with the discharge module and the battery. This loop dissipates excess energy in the external circuit due to the engine load being disconnected, through the discharge module, effectively absorbing and suppressing the impact of high-voltage surges on the battery pack and other electronic components.

[0067] In a preferred embodiment, the detection module can be constructed using an analog front-end chip, an op amp comparator, or a voltage divider in conjunction with an ADC module. The control module can be a microcontroller (MCU) or a digital logic controller with a voltage comparison function. The discharge module can include a power resistor connected in series with a power MOS transistor, with the gate of the MOS transistor controlled by the control module.

[0068] When the discharge circuit is connected, the power devices within the discharge module convert the high-voltage current into heat energy for release, effectively suppressing surge voltage and reducing battery impact. This solution, through a sequential logic of detection, control, and discharge, ensures timely and reliable circuit response. It is suitable for various vehicle power systems including engine generators, and is particularly well-suited for load-dump protection in new energy vehicles, hybrid systems, or high-power generators.

[0069] Furthermore, the detection module includes a sampling resistor, and the detection module includes an AFE acquisition chip;

[0070] The input end of the sampling resistor is connected to the negative electrode of the battery, and the output end is connected to the input end of the AFE acquisition chip;

[0071] The input end of the sampling resistor converts the detection current into a detection voltage in response to the detection current of the negative electrode of the battery, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module;

[0072] When the detection voltage is greater than or equal to a preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

[0073] Figure 2 This is a circuit diagram of the engine load dump high-voltage surge suppression circuit provided in this application.

[0074] right Figure 2 The symbols of the electronic components mentioned in the figure correspond to the descriptions in this application, and the following meanings are equivalent and no further description is required. Figure 2 As shown, the sampling resistor RS, the first resistor R1, the second resistor R2, the third resistor R3, the fourth resistor R4, the fifth resistor R5, the sixth resistor R6, the seventh resistor R7, the first NPN transistor NPN1, the second NPN transistor NPN2, the first PNP transistor PNP1, the second PNP transistor PNP2, the first crystal diode D1, the second crystal diode D2, the third crystal diode D3, and the fourth crystal diode D4.

[0075] In this embodiment of the present application, the detection module in the engine load-dump high-voltage surge suppression circuit includes a sampling resistor and an AFE (Analog Front End) acquisition chip. The sampling resistor's input is connected to the battery's negative terminal to receive the current signal flowing through the battery's negative terminal, and the sampling resistor's output is connected to the AFE's input.

[0076] During operation, when the battery is discharging or charging, actual current flows through its negative electrode. The sampling resistor responds to this sensed current by converting it into a corresponding voltage signal based on Ohm's law (U = IR), generating a sensed voltage. This sensed voltage varies with the magnitude of the negative electrode current and reflects the degree of current surge experienced by the battery in the power circuit.

[0077] The output of the sampling resistor transmits the detected voltage to the input of the AFE acquisition chip in real time. The AFE chip collects, filters, and performs A / D conversion on the received detected voltage, and outputs the converted voltage value to the control module for subsequent judgment.

[0078] When the detection voltage is greater than or equal to a preset threshold voltage, the system determines that the current battery operating state is abnormal, and the detection voltage is identified as a first detection voltage. After responding to the first detection voltage, the AFE acquisition chip immediately outputs it to the input terminal of the control module as a criterion for triggering load dump protection.

[0079] Through this structure, the detection module accurately converts current signals into voltage information. Using the AFE chip, it achieves high-precision data acquisition and transmission, providing a reliable basis for the control module's load-dump protection decisions. This simple structure and fast response make it suitable for vehicle power management systems that require real-time monitoring of current anomalies, effectively enhancing the system's ability to cope with surge voltages.

[0080] Furthermore, the control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit and a discharge resistor, and the discharge switch unit includes a discharge switch unit first end, a discharge switch unit control end and a discharge switch unit second end;

[0081] The input end of the discharge signal unit is connected to the first output end of the control module, and the output end is connected to the negative electrode of the battery;

[0082] The first end of the discharge switch unit is connected to the first end of the discharge resistor, the control end of the discharge switch unit is connected to the positive electrode of the battery, and the second end of the discharge switch unit is connected to the output end of the discharge signal unit;

[0083] The second end of the discharge resistor is connected to the first end of the discharge switch unit;

[0084] The control end of the discharge switch unit turns on the discharge switch unit in response to the voltage of the positive electrode of the battery, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0085] In the embodiment of the present application, the control module includes an MCU control chip, and the discharge module includes: a discharge signal unit, a discharge switch unit, and a discharge resistor. The discharge switch unit is generally an N-channel MOS transistor, the first end of the discharge unit is the source, the control end of the discharge unit is the gate, and the second end of the discharge unit is the drain.

[0086] In actual applications, the MCU control chip serves as the core component of the control module, and its first output end is electrically connected to the input end of the discharge signal unit for outputting a control signal; the output end of the discharge signal unit is connected to the negative pole of the battery for forming a discharge path.

[0087] The first end of the discharge switch unit is connected to the first end of the discharge resistor to form a part of the current path; the control end of the discharge switch unit is connected to the positive electrode of the battery to receive the drive of the positive electrode voltage; the second end of the discharge switch unit is connected to the output end of the discharge signal unit, thereby ultimately achieving connection with the negative electrode of the battery.

[0088] The second end of the bleeder resistor is also connected to the first end of the bleeder switch unit, so that the bleeder resistor forms a closed current path. This structure ensures that when the bleeder switch unit is turned on, the bleeder resistor is located between the positive and negative electrodes of the battery, that is, in parallel with the battery.

[0089] In this embodiment, when the MCU receives the first detection voltage from the detection module, it determines that the system is at risk of overvoltage or surge and issues a first control signal. This signal is processed by the discharge signal unit and then directs the control terminal of the discharge switch unit to sense the voltage at the battery's positive electrode, thereby quickly turning on the switch device.

[0090] The bleeder switch unit can use a MOSFET or IGBT device. When it turns on, it allows the battery's positive electrode voltage to flow to the negative electrode through the bleeder resistor, forming a parallel bleeder path between the battery and the bleeder resistor. This path is used to dissipate excess energy, absorb high-voltage surges during load dump, and reduce the impact on the battery pack and power management system.

[0091] Through this structural design, the entire discharge control process has the characteristics of fast response speed, clear structure and simple implementation. It can effectively improve the stability and safety of the vehicle's electrical system under sudden working conditions. It is particularly suitable for new energy vehicles, hybrid vehicles and industrial engine systems.

[0092] Figure 2 This is a circuit diagram of the engine load dump high-voltage surge suppression circuit provided in this application.

[0093] Furthermore, the discharge signal unit includes a first resistor and an optical coupler;

[0094] The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optical coupler;

[0095] The output end of the optical coupler is connected to the negative electrode of the battery and the second end of the discharge switch unit;

[0096] The control end of the discharge switch unit is turned on in response to a high voltage level at the positive electrode of the battery, and the first end of the discharge switch unit is connected to the second end of the discharge switch unit, so that the first end of the discharge resistor is connected to the positive electrode of the battery, the second end of the discharge resistor is connected to the negative electrode of the battery, and the discharge resistor is connected in parallel with the battery.

[0097] In an embodiment of the present application, the structure and connection method of the discharge signal unit are as follows: the input end of the first resistor is connected to the first output end of the control module (such as the MCU control chip) for receiving the first control signal from the control module; the output end of the first resistor is connected to the input end of the optocoupler for current limiting and level conversion; the output end of the optocoupler is connected to the negative electrode of the battery and the second end of the discharge switch unit.

[0098] When the battery's positive terminal is at a high level (e.g., 12V or higher system voltage) and the optocoupler output is pulled low, the bleeder switch unit (e.g., an N-channel MOS transistor) turns on due to the Vgs > threshold voltage condition. Once turned on, a low-resistance channel is formed between its first and second terminals. In this parallel circuit, the bleeder resistor, along with the battery's positive and negative terminals, completes the circuit, absorbing residual charge or surge energy in the external circuit during a load dump event. This prevents high-voltage shocks from damaging system components and ensures the stability and safety of the vehicle's power system.

[0099] The above structural design enables control signals to be transmitted through optoelectronic isolation, ensuring electrical isolation between the MCU and the high-voltage side. The discharge action is controlled by the optocoupler's low-end switch. The structure is safe and reliable, the parallel discharge path conducts quickly, and the response is sensitive, making it suitable for scenarios with rapid response to voltage surges.

[0100] Furthermore, the discharge module also includes a second resistor, a first NPN transistor, a third resistor, a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor.

[0101] The input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN transistor;

[0102] The emitter of the first NPN transistor is connected to the input end of the third resistor;

[0103] The output end of the third resistor is connected to the emitter of the first PNP transistor;

[0104] The collector of the first PNP transistor is connected to the anode of the first crystal diode;

[0105] The cathode of the first crystal diode is connected to the anode of the second crystal diode;

[0106] The cathode of the second crystal diode is connected to the input end of the fourth resistor;

[0107] The output end of the fourth resistor is connected to the control end of the discharge switch unit.

[0108] In an embodiment of the present application, in order to further enhance the response capability of the discharge module to load dump high voltage surges under different working conditions, this embodiment further introduces a multi-stage voltage control and triggering structure based on the aforementioned discharge module, including: a second resistor, a first NPN transistor, a third resistor, a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor.

[0109] The above-mentioned device constitutes an auxiliary trigger circuit for controlling the conduction state of the discharge switch unit. Its structure and function are as follows: the input end of the second resistor is connected to the positive terminal of the battery, and the output end is connected to the collector of the first NPN transistor. The second resistor is used to limit the current and provide a suitable bias voltage for the NPN transistor. The emitter of the first NPN transistor is connected to the input end of the third resistor; the output end of the third resistor is further connected to the emitter of the first PNP transistor. This structure forms a voltage-driven amplification chain for realizing the conduction control of the PNP transistor. The collector of the first PNP transistor is connected to the positive terminal of the first crystal diode, forming a signal transmission path; the cathode of the first crystal diode is connected to the positive terminal of the second crystal diode. The two diodes are connected in series to limit the voltage direction and protect the subsequent devices.

[0110] The cathode of the second transistor is connected to the input of the fourth resistor, and the output of the fourth resistor is ultimately connected to the control terminal (Gate) of the discharge switch unit. With this circuit structure, when a high-level signal appears at the positive terminal of the battery, voltage flows through the second resistor and enters the first NPN transistor. If this voltage reaches the bias condition for the NPN transistor to turn on, it turns on, directing emitter current into the third resistor, triggering the PNP transistor to turn on. Once the PNP transistor turns on, its collector output voltage forms a unidirectional path through the first and second transistors. After current limiting by the fourth resistor, it is transmitted to the control terminal of the discharge switch unit. Receiving the stable driving voltage from the PNP transistor, the control terminal reliably turns on the discharge switch unit.

[0111] This auxiliary circuit design offers the following advantages: Transistors form a stable voltage amplification and isolation stage, enhancing drive capability. Series diodes provide unidirectional conduction protection, preventing reverse breakdown. Resistor current limiting ensures current safety at each pin level and prevents drive voltage overshoot. The overall structure enhances the anti-interference capability and response accuracy of the discharge control channel, making it suitable for rapid surge peak shaving in load dump scenarios. This structure is particularly suitable for power modules in high-voltage systems with frequent load dump events and high protection accuracy requirements, serving as a key protection branch in engine power management systems.

[0112] Furthermore, the control module further includes a charging switch unit. When the discharge switch unit is turned on and the discharge resistor is connected in parallel with the battery, the second output terminal of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit.

[0113] The charging switch unit is turned off in response to the second signal to disconnect the external circuit from the battery.

[0114] Furthermore, the charging switch unit includes a charging switch unit first end, a charging switch unit control end and a charging switch unit second end;

[0115] The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control end of the charging switch unit is connected to the second output end of the MCU control chip;

[0116] The charging switch unit control end disconnects the first end of the charging switch unit from the second end of the charging switch unit in response to the second signal, thereby disconnecting the negative electrode of the external circuit from the negative electrode of the battery, and causing the external circuit to stop charging the battery.

[0117] To further enhance the overall responsiveness and circuit safety of the load-dump high-voltage surge suppression circuit, this embodiment also incorporates a charging switch unit into the control module. This unit is used to promptly disconnect the external circuit from the battery after the bleeder resistor and the battery form a parallel path, thereby preventing system instability or malfunction caused by continuous charging during a surge.

[0118] Specifically, the control module includes not only an MCU control chip and the aforementioned first output terminal linked to the discharge module, but also a second output terminal for controlling charging on and off. After the MCU control chip detects a load dump state and turns on the discharge switch unit, its second output terminal outputs a second signal, which is transmitted to the charging switch unit to control its operation.

[0119] The charging switch unit includes: a first end of the charging switch unit, used to be connected to the negative end of the external circuit; a second end of the charging switch unit, connected to the negative pole of the battery; and a control end of the charging switch unit, used to receive a second signal from the second output end of the MCU.

[0120] Under normal operating conditions, the charging switch unit is turned on, allowing the external circuit to form a closed charging loop with the negative terminal of the battery. When the engine system detects a load dump condition, the control module controls the discharge switch unit via its first output terminal to turn on, creating a parallel path between the discharge resistor and the battery to absorb excess energy from the external circuit. Simultaneously, the MCU control chip's second output terminal outputs a high level or shutdown signal (i.e., a second signal), triggering the charging switch unit to operate.

[0121] Upon receiving this second signal, the charging switch unit responds by shutting off the conduction between its first and second terminals, effectively disconnecting the negative terminal of the external circuit from the negative terminal of the battery. This prevents the external circuit from continuing to supply energy to the battery during a load dump, potentially causing the risk of system mischarging or backflow. This also isolates the external load from power failure, improving the system's overall safety recovery capabilities after a surge response. Working in conjunction with the discharge module, this unit forms a complete surge control and power switching path.

[0122] Preferably, the charging switch unit can be composed of a MOSFET device with fast response capability. When its control terminal receives a second signal (for example, a low level), the connection between its Source terminal (connected to the negative electrode of the battery) and the Drain terminal (connected to the external load) is cut off, thereby forming an effective electrical disconnection.

[0123] The control strategy in this embodiment implements the dual response of "surge discharge + load disconnection", improving the electrical isolation efficiency and system reliability during the load dump process. It is suitable for scenarios such as new energy vehicle engine power supply systems, hybrid system high-voltage side load management, and industrial power generation system power supply protection.

[0124] Furthermore, the control module also includes a fifth resistor, a second NPN transistor, a sixth resistor, a second PNP transistor, a third crystal diode, a fourth crystal diode and a seventh resistor.

[0125] Furthermore, the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN transistor;

[0126] The collector of the second NPN transistor is connected to the input end of the sixth resistor;

[0127] The output end of the sixth resistor is connected to the base of the second PNP transistor;

[0128] The collector of the second PNP transistor is connected to the anode of the third crystal diode;

[0129] The cathode of the third crystal diode is connected to the anode of the fourth crystal diode;

[0130] The cathode of the fourth crystal diode is connected to the input end of the seventh resistor;

[0131] The output end of the seventh resistor is connected to the control end of the charging switch unit.

[0132] In an embodiment of the present application, in order to improve the control accuracy and driving capability of the control module over the charging switch unit, in this embodiment, a group of signal amplification and isolation driving circuits composed of transistors, resistors and diodes are further provided to realize the effective level output of the control end of the charging switch unit.

[0133] The circuit structure includes the following elements: a fifth resistor, a second NPN transistor, a sixth resistor, a second PNP transistor, a third crystal diode, a fourth crystal diode, and a seventh resistor.

[0134] The circuit connection relationship of the above components is as follows: the input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN transistor. This structure is used to limit current and provide bias voltage to control the conduction of the second NPN transistor.

[0135] The collector of the second NPN transistor is connected to the input end of the sixth resistor to form a current channel, and the output end of the sixth resistor is connected to the base of the second PNP transistor to provide bias current to drive the PNP transistor.

[0136] The collector of the second PNP transistor is connected to the anode of the third crystal diode, the cathode of the third crystal diode is connected to the anode of the fourth crystal diode, and the diodes are connected in series for direction control and prevention of reverse breakdown.

[0137] The cathode of the fourth crystal diode is connected to the input end of the seventh resistor, and finally the output end of the seventh resistor is connected to the control end of the charging switch unit.

[0138] The specific working process of this circuit is as follows: when the second output terminal of the MCU control chip detects a load dump situation and sends a control signal (second signal), the electrical signal is input to the base of the second NPN transistor after current limiting by the fifth resistor; the second NPN transistor is turned on after obtaining sufficient bias voltage, and a current path is formed between its collector and emitter, driving a voltage drop across the sixth resistor; this voltage drop is applied to the base of the second PNP transistor, causing it to turn on, and the collector output voltage is transmitted to the seventh resistor after passing through the third and fourth crystal diodes connected in series; the seventh resistor further limits the current and transmits the signal voltage to the control terminal of the charging switch unit, controlling its state to become disconnected.

[0139] This structural design offers the following advantages: A two-stage transistor-based voltage amplification and level isolation chain enhances signal drive strength and interference immunity. A series-connected transistor diode provides a unidirectional conduction path and protects the PNP transistor output from reverse breakdown. Multi-stage current-limiting resistors ensure current flow safety at each circuit level, adapting to a wide range of operating voltages. This ensures reliable driving of the charging switch unit even when the MCU control chip's output drive capability is limited, improving overall system responsiveness and robustness.

[0140] Through the above structural settings, the MCU control module can implement linkage control of the discharge path and the external load circuit. When a load dump surge occurs, it can not only safely release energy through the discharge module, but also disconnect the charging path through the charging switch unit to avoid risks such as mischarging and breakdown, thereby comprehensively improving the safety performance and control intelligence level of the high-voltage system.

[0141] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of this embodiment.

[0142] Through the description of the above embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a general hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the relevant technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0143] It should be understood that the terms used herein are for the purpose of describing specific example embodiments only and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "comprise", "include", "contain" and "have" are inclusive and therefore specify the presence of stated features, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring them to be performed in the specific order described or illustrated, unless the order of execution is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0144] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An engine load dump high voltage surge suppression circuit, characterized in that: The engine load dump high voltage surge suppression circuit includes a detection module, a control module, and a discharge module; The input end of the detection module is connected to the negative electrode of the battery, and the output end is connected to the input end of the control module; The first output terminal of the control module is connected to the first terminal of the discharge module; The second end of the discharge module is connected to the positive electrode of the external circuit of the engine; The third end of the discharge module is connected to the negative electrode of the battery and the negative electrode of the external circuit; The control module includes an MCU control chip, the discharge module includes a discharge signal unit, a discharge switch unit and a discharge resistor, and the discharge switch unit includes a discharge switch unit first end, a discharge switch unit control end and a discharge switch unit second end; The input end of the discharge signal unit is connected to the first output end of the control module, and the output end is connected to the discharge switch control end; The first end of the discharge switch unit is connected to the first end of the discharge resistor; The second end of the bleeder resistor is connected to the positive electrode of the external circuit; The second end of the discharge switch unit is connected to the negative electrode of the external circuit; The discharge signal unit includes a first resistor and an optical coupler; The input end of the first resistor is connected to the first output end of the control module, and the output end is connected to the input end of the optical coupler; The output end of the optical coupler is connected to the control end of the discharge switch unit; The discharge module further includes a first PNP transistor, a first crystal diode, a second crystal diode, and a fourth resistor; The collector of the first PNP transistor is connected to the anode of the first crystal diode; The base of the first PNP transistor is connected to the output end of the optical coupler; The cathode of the first crystal diode is connected to the anode of the second crystal diode; The cathode of the second crystal diode is connected to the input end of the fourth resistor; The output terminal of the fourth resistor is connected to the control terminal of the discharge switch unit; the detection module transmits the first detection voltage to the input terminal of the control module in response to the first detection voltage, wherein the first detection voltage is a voltage greater than a preset threshold voltage; The control module outputs a first signal in response to the first detection voltage and transmits the first signal to the first resistor, and the first resistor responds to the first signal and transmits the first signal to the optical coupler; The optical coupler transmits the first signal to the control end of the discharge switch unit through the first PNP transistor, the first crystal diode, the second crystal diode and the fourth resistor; The control end of the discharge switch unit is turned on in response to the first signal, so that the second end of the discharge module and the third end of the discharge module are connected, forming a parallel loop between the discharge module and the external circuit, so that the discharge module serves as a load of the external circuit to discharge the external circuit.

2. The engine load dump high voltage surge suppression circuit according to claim 1, characterized in that: The detection module includes a sampling resistor, and the detection module includes an AFE acquisition chip; The input end of the sampling resistor is connected to the negative electrode of the battery, and the output end is connected to the input end of the AFE acquisition chip; The input end of the sampling resistor converts the detection current into a detection voltage in response to the detection current of the negative electrode of the battery, and the output end of the sampling resistor transmits the detection voltage to the input end of the detection module; When the detection voltage is greater than or equal to a preset threshold voltage, the detection voltage is the first detection voltage, and the input end of the AFE acquisition chip responds to the first detection voltage and transmits the first detection voltage to the input end of the control module.

3. The engine load dump high voltage surge suppression circuit according to claim 1, characterized in that: The discharge module further includes a second resistor, a first NPN transistor, and a third resistor; The input end of the second resistor is connected to the positive electrode of the battery, and the output end is connected to the collector of the first NPN transistor; The emitter of the first NPN transistor is connected to the input end of the third resistor; The output end of the third resistor is connected to the emitter of the first PNP transistor; The second resistor responds to a high level of the positive electrode of the battery and transmits the high level to the collector of the first NPN transistor; The collector of the first NPN transistor is turned on in response to the high level, and transmits the high level to the third resistor; The third resistor responds to the high level and transmits the high level to the emitter of the first PNP transistor; The optical coupler responds to the first signal and transmits the first signal to the base of the first PNP transistor; The emitter of the first PNP transistor responds to the high level of the positive electrode of the battery, and the base of the first PNP transistor responds to the first signal, so that the first PNP transistor is turned on.

4. The engine load dump high voltage surge suppression circuit according to claim 1, characterized in that: The control module further includes a charging switch unit. When the discharge switch unit is turned on and the discharge resistor is connected in parallel with the battery, the second output terminal of the MCU control chip outputs a second signal and transmits the second signal to the charging switch unit. The charging switch unit is turned off in response to the second signal to disconnect the external circuit from the battery.

5. The engine load dump high voltage surge suppression circuit according to claim 4, characterized in that: The charging switch unit includes a charging switch unit first terminal, a charging switch unit control terminal and a charging switch unit second terminal; The first end of the charging switch unit is connected to the external circuit, the second end of the charging switch unit is connected to the negative electrode of the battery, and the control end of the charging switch unit is connected to the second output end of the MCU control chip; The charging switch unit control end disconnects the first end of the charging switch unit from the second end of the charging switch unit in response to the second signal, thereby disconnecting the negative electrode of the external circuit from the negative electrode of the battery, and causing the external circuit to stop charging the battery.

6. The engine load dump high voltage surge suppression circuit according to claim 4, characterized in that: The control module further includes a fifth resistor, a second NPN transistor, a sixth resistor, a second PNP transistor, a third crystal diode, a fourth crystal diode and a seventh resistor; The input end of the fifth resistor is connected to the second output end of the MCU control chip, and the output end is connected to the base of the second NPN transistor; The collector of the second NPN transistor is connected to the input end of the sixth resistor; The output end of the sixth resistor is connected to the base of the second PNP transistor; The collector of the second PNP transistor is connected to the anode of the third crystal diode; The emitter of the second PNP transistor is coupled to a port of the AFE acquisition chip; The cathode of the third crystal diode is connected to the anode of the fourth crystal diode; The cathode of the fourth crystal diode is connected to the input end of the seventh resistor; The output end of the seventh resistor is connected to the control end of the charging switch unit.

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