Overvoltage protection device

Abstract

An overvoltage protection device includes: a power conditioning module, the input of which is connected to a vehicle battery and the output of which is connected to an overvoltage protection circuit, for converting the vehicle battery voltage into a system front-end voltage and supplying it to the overvoltage protection circuit; an overvoltage protection circuit, composed of multiple discrete electronic components, for detecting whether the front-end voltage exceeds an overvoltage protection threshold, and cutting off the main power supply to a microcontroller module when an overvoltage is detected; and a microcontroller module, connected to the output of the overvoltage protection circuit, for receiving the power supplied by the overvoltage protection circuit and implementing system control functions. This overvoltage protection device enables low-cost, discrete component overvoltage protection of sensitive electronic components, offering flexible adaptation, self-diagnosis capabilities, and improved reliability and maintenance convenience.

Description

Technical Field

[0001] This utility model relates to an overvoltage protection device, and more specifically, to an overvoltage protection and self-diagnostic circuit suitable for vehicle power systems. It can achieve overvoltage protection for sensitive electronic components such as microcontrollers using low-cost discrete components, and belongs to the field of power protection and diagnostic technology in vehicle electronic systems. Background Technology

[0002] In the field of automotive electronics technology, with the popularization and tightening of automotive functional safety standards, automotive electronic systems, especially controllers involving the power domain, chassis domain and smart cockpit domain, need to meet the clear automotive safety integrity level (ASIL) requirements. Among them, ASIL-B is the mainstream safety level for medium safety risk scenarios (such as body control and driver assistance perception modules).

[0003] In such systems, sensitive electronic components such as microcontrollers (MCUs), sensors, and actuators have extremely high requirements for the stability of the power supply voltage. Instantaneous voltage spikes (such as overvoltages caused by load changes, power fluctuations, or electromagnetic interference) can easily lead to component burnout, data loss, or functional failure, thereby causing safety hazards. Therefore, on-board overvoltage protection and diagnostic circuits have become a core component for ensuring system reliability and functional safety.

[0004] Previously, the design of vehicle overvoltage protection devices generally relied on integrated power management solutions, primarily using power management integrated circuits (PMICs) and system base chips (SBCs) as core components. For example... Figure 5 As shown, a typical design scheme uses PMIC / SBC as the core. After drawing power from the vehicle battery voltage, the PMIC outputs 5V voltage to the microcontroller (MCU) through the DC-DC converter (DCDC) module integrated inside. It also integrates overvoltage protection, undervoltage protection, fault diagnosis and other functions to meet ASIL-B level functional safety requirements.

[0005] The advantages of this integrated solution are: high integration, which reduces board space occupation; modular functionality, which reduces the complexity of early circuit topology design; and automotive-grade reliability verification (e.g., AEC-Q100), which can adapt to harsh conditions such as high temperature, vibration, and salt spray in the automotive environment. Therefore, it is widely used in mid-to-high-end automotive electronic systems.

[0006] However, existing PMIC / SBC-based overvoltage protection solutions have significant technical shortcomings, making it difficult to meet the current automotive electronics industry's demands for "low cost, high flexibility, and simplified design." The specific deficiencies are as follows: - High Costs: As highly integrated automotive-grade devices, PMICs / SBCs have significantly higher material costs than discrete components. At the same time, to ensure functional stability, they require dedicated external matching components (such as high-precision capacitors, inductors, and feedback resistors). These components need to be precisely matched with the internal circuit parameters of the PMIC (for example, the inductance value of the DC-DC module needs to match the output current specification, and the feedback resistor needs to be calibrated for the voltage threshold). This further increases the cost of component procurement and subsequent debugging. The high cost problem is particularly prominent in the mass application of low-end and mid-range vehicles or non-core controllers (such as window control and lighting control modules).

[0007] - Complex design and long development cycle: The internal architecture of PMIC / SBC is complex (e.g., integrating multi-channel power output and multi-level safety diagnostic logic). Its functional safety design concept needs to match the ASIL-B level verification requirements of ISO26262, including Failure Mode and Effects Analysis (FMEA) and safety mechanism verification (such as hardware redundancy and diagnostic coverage testing). This requires R&D personnel to have professional integrated device debugging capabilities and to invest more time in safety documentation writing and verification testing, thus extending the product development cycle.

[0008] Furthermore, if it is necessary to adapt to different MCU models or adjust the power supply voltage specifications (such as switching from 5V to 3.3V), the external circuit topology and software configuration of the PMIC need to be re-optimized, resulting in poor flexibility.

[0009] - High cost of troubleshooting and repair: In integrated solutions, internal faults of PMIC / SBC (such as failure of overvoltage protection module) are difficult to locate directly through external testing. Fault analysis requires the use of special debugging tools (such as PMIC diagnostic instrument), which increases the difficulty and cost of later maintenance. Moreover, once PMIC / SBC is damaged, the entire device needs to be replaced, and it cannot be repaired by replacing a single component, which further increases the cost of after-sales maintenance.

[0010] In summary, while existing PMIC / SBC-based automotive overvoltage protection solutions can meet ASIL-B functional safety requirements, they have significant shortcomings in cost control, design flexibility, and maintenance convenience. Not only are they significantly more expensive, but their functional safety design concepts are also more complex, making them difficult to adapt to the current trend of automotive electronic systems moving towards "low cost, high adaptability, and simplified R&D".

[0011] Therefore, there is an urgent need for an on-board overvoltage protection and diagnostic technology that can balance functional safety requirements and cost control, simplify the design process, and have good adaptability, in order to solve the above-mentioned defects of the existing technology. Utility Model Content

[0012] This disclosure is made to solve the above-mentioned technical problems, and its purpose is to provide an overvoltage protection device that can achieve overvoltage protection of sensitive electronic components with low-cost discrete components, meet ASIL-B level requirements, simplify design, reduce costs, and is flexible in adaptation, self-diagnostic, and improve reliability and maintenance convenience.

[0013] To achieve the purpose of this disclosure, an overvoltage protection device is provided, which is applicable to vehicle power supplies, and the overvoltage protection device includes: The power conditioning module has its input terminal connected to the vehicle battery and its output terminal connected to the overvoltage protection circuit. It is used to convert the voltage of the vehicle battery into the system front-end voltage and supply it to the overvoltage protection circuit. The overvoltage protection circuit, composed of multiple discrete electronic components, is used to detect whether the preceding voltage exceeds the overvoltage protection threshold, and to cut off the main power supply to the microcontroller module when an overvoltage is detected; and The microcontroller module is connected to the output terminal of the overvoltage protection circuit and is used to receive the power supply provided by the overvoltage protection circuit and to realize the control function of the system.

[0014] Based on the above configuration, an overvoltage protection circuit is constructed using discrete electronic components, replacing the traditional high-cost PMIC / SBC integrated solution, which can significantly reduce the material cost of the vehicle power system. At the same time, it is suitable for vehicle scenarios, can effectively detect overvoltage and cut off the main power supply, and avoid damage to sensitive components such as microcontrollers due to overvoltage, thereby ensuring the basic power supply safety of the vehicle electronic system.

[0015] Preferably, the above-mentioned overvoltage protection circuit includes a detection and comparison module and a power switch module. The input terminal of the aforementioned detection and comparison module is connected to the output terminal of the aforementioned power regulation module, and is used to detect whether the aforementioned front-end voltage exceeds the overvoltage protection threshold. The input terminal of the aforementioned power switch module is connected to the output terminal of the aforementioned power regulation module, the control terminal is connected to the output terminal of the aforementioned detection and comparison module, and the output terminal is connected to the aforementioned microcontroller module, and is used to cut off the main power supply to the aforementioned microcontroller module when an overvoltage is detected.

[0016] Based on the above configuration, the overvoltage protection circuit is split into a detection and comparison module and a power switch module, which can realize the separation of "detection-execution" functions and improve the accuracy and timeliness of overvoltage response. The detection and comparison module focuses on threshold judgment, and the power switch module focuses on power supply cut-off, avoiding protection delay or malfunction caused by overload of a single module function, and further ensuring the power supply safety of the microcontroller.

[0017] Preferably, the detection and comparison module includes an overvoltage triggering module and a reference comparator module. The input terminal of the overvoltage trigger module is connected to the pre-stage voltage and overvoltage trigger signal output by the power supply regulation module, and the output terminal is connected to the reference comparator module. The aforementioned reference comparator module uses a bandgap reference as a reference to compare and judge the output of the aforementioned overvoltage trigger module, and outputs a cut-off control signal to the aforementioned power switch module when an overvoltage is confirmed.

[0018] Based on the above configuration, the reference comparator module with the bandgap reference as the reference has high voltage stability, which can avoid the deviation of the overvoltage detection threshold caused by reference drift and reduce the risk of false or false detection. The overvoltage trigger module works in conjunction with the reference comparator module to achieve accurate capture and judgment of overvoltage signals, providing a reliable basis for subsequent disconnection of the main power supply, thereby effectively improving the accuracy of overvoltage detection.

[0019] Preferably, the input terminal of the power switch module is connected to the pre-amplifier voltage output by the power regulation module, and the control terminal receives the level signal output by the detection and comparison module. When no overvoltage is detected, the power switch module provides main power to the microcontroller module; when it receives the toggle level signal output by the detection and comparison module, it cuts off the main power supply.

[0020] As described above, the power switch module switches between "power supply" and "disconnection" states based on the level signal from the detection and comparison module. Under normal operating conditions, it stably provides main power to the microcontroller, effectively ensuring the normal operation of the system. In case of overvoltage, it responds to the flip-level signal to quickly disconnect the power supply, preventing continuous overvoltage input to the microcontroller from causing component burnout, thus achieving rapid protection in overvoltage scenarios.

[0021] Preferably, the overvoltage protection device further includes a self-diagnostic circuit, which is connected in parallel with the overvoltage protection circuit and whose input terminal is connected to the output terminal of the power conditioning module, for diagnosing the functional status of the overvoltage protection circuit. The microcontroller module is also connected to the self-diagnostic circuit to receive diagnostic signals output by the self-diagnostic circuit and to send control signals to the self-diagnostic circuit.

[0022] Based on the above configuration, the newly added self-diagnostic circuit can detect functional faults in the overvoltage protection circuit in advance (such as detection module failure or switch module jamming), solving the problem of difficult fault location in traditional integrated solutions; the microcontroller can monitor the status of the protection circuit in real time through diagnostic signals, support preventive maintenance, avoid safety hazards when overvoltage protection fails, and thus effectively improve the overall reliability of the vehicle system.

[0023] Preferably, the self-diagnostic circuit includes a backup switch module and an analog-to-digital converter module. The input terminal of the aforementioned backup switch module is connected to the output terminal of the aforementioned power regulation module, the control terminal is connected to the aforementioned analog-to-digital conversion module, and the output terminal is connected to the aforementioned microcontroller module, for providing backup power to the aforementioned microcontroller module. The aforementioned analog-to-digital conversion module is connected to the aforementioned microcontroller module and the aforementioned overvoltage protection circuit. It is used to acquire voltage signals and convert them into digital signals, and output overvoltage diagnostic signals to the aforementioned microcontroller module.

[0024] As described above, the backup switch module can provide continuous power to the microcontroller when the main power supply is cut off, ensuring that the microcontroller does not crash during the self-diagnosis process; the analog-to-digital converter module converts the analog voltage signal into a digital diagnostic signal, improving the accuracy of the diagnostic data, allowing the microcontroller to clearly determine the working status of the overvoltage protection circuit, thereby effectively avoiding fault misjudgment caused by ambiguous diagnostic signals.

[0025] Preferably, the output of the backup switch module is divided into two paths: one path is connected to the microcontroller module to provide backup power, and the other path is connected to the voltage acquisition terminal of the analog-to-digital converter module to provide voltage sampling signals to the analog-to-digital converter module.

[0026] As described above, the backup switch module has a two-way output design, which not only ensures backup power for the microcontroller when the main power supply is cut off, but also provides a stable voltage sampling source for the analog-to-digital converter module. This effectively avoids mutual interference between the sampling signal and the power supply signal, ensuring that the voltage data collected by the analog-to-digital converter module truly reflects the circuit status, and further improves the reliability of the self-diagnostic results.

[0027] Preferably, a diode is connected in series between the output terminal of the backup switch module and the microcontroller module. The aforementioned diode is used to achieve unidirectional conduction to prevent reverse voltage flow and to step down the voltage output from the aforementioned backup switch module to match the operating voltage requirements of the aforementioned microcontroller module.

[0028] As described above, the series-connected diodes have the dual functions of preventing reverse backflow and stepping down voltage. On the one hand, they can prevent the voltage on the microcontroller side from flowing back into the backup switch module and causing circuit damage. On the other hand, they can adapt to the microcontroller's operating voltage without the need for additional step-down components, which can simplify the circuit topology and reduce component costs. At the same time, they can effectively ensure the stability of the backup power supply so as to ensure that the microcontroller works normally during self-diagnosis.

[0029] Preferably, the diode is positioned between the output terminal of the power switch module and the output terminal of the standby switch module. One end is connected to the output terminal of the aforementioned backup switch module, and the other end is connected to the power supply port of the aforementioned microcontroller module.

[0030] As described above, the diode's position design takes into account both the main and backup power supply circuits, which can simultaneously prevent reverse voltage flow between the main and backup power supply circuits and avoid circuit logic confusion during main and backup power supply switching; at the same time, it can accurately connect to the microcontroller's power supply port to ensure stable input of the stepped-down voltage, thereby improving the smoothness and reliability of main and backup power supply switching.

[0031] Preferably, during the self-diagnostic process, the microcontroller module can actively control the detection and comparison module to flip the output signal, thereby triggering the power switch module to cut off the main power supply. The microcontroller module is powered by the backup power output from the backup switch module, and determines whether the overvoltage protection circuit is functioning properly by reading the voltage value at the port of the analog-to-digital converter module.

[0032] Based on the above configuration, the microcontroller's active triggering of self-diagnosis design can simulate overvoltage scenarios to verify the protection circuit function, ensuring that the overvoltage protection circuit can work normally in actual faults; the backup power supply ensures that the self-diagnosis process is not interrupted, and the method of reading the voltage value of the analog-to-digital conversion module can intuitively determine the status of the protection circuit, avoiding the safety risks caused by the "virtual" protection circuit, and meeting the requirements of ASIL-B level functional safety for automotive electronics for diagnostic coverage. Attached Figure Description

[0033] With reference to the above objectives, the technical features of this utility model are clearly described in the following technical solutions, and its advantages are apparent from the following detailed description with reference to the accompanying drawings, which illustrate preferred embodiments of this utility model by way of example, without limiting the scope of the inventive concept.

[0034] Figure 1 This is a schematic diagram of the power management principle of the overvoltage protection device of this utility model.

[0035] Figure 2 This is a block diagram illustrating the power management principle of the overvoltage protection device of this utility model.

[0036] Figure 3 This is a schematic diagram of the circuit principle structure of the overvoltage protection device of this utility model.

[0037] Figure 4 This is a flowchart illustrating the self-diagnosis process in the overvoltage protection device of this utility model.

[0038] Figure 5 This is a schematic diagram illustrating the power management principle of a conventional overvoltage protection device.

[0039] Symbol Explanation 1. Power regulation module; 2. Overvoltage protection circuit; 21. Detection and comparison module; 211 Overvoltage triggering module; 212 Reference Comparator Module; 22. Power switch module; 3. Self-diagnostic circuit; 31. Backup switch module; 32. Analog-to-digital conversion module; 4. Microcontroller module. Detailed Implementation

[0040] Various embodiments of the present invention will now be described in detail, examples of which are shown in the accompanying drawings.

[0041] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0042] The following is for reference Figure 1 The overall structure of the overvoltage protection device of this utility model is described in detail below.

[0043] like Figure 1 As shown, the overvoltage protection device of this utility model mainly includes a power regulation module 1, an overvoltage protection circuit 2, a self-diagnostic circuit 3, and a microcontroller module 4. The modules are connected by circuits and cooperate with each other to realize overvoltage detection, protection, and self-diagnosis functions, so as to ensure the safe and stable operation of the MCU.

[0044] The input terminal of the aforementioned power conditioning module 1 is connected to the vehicle's battery voltage VBAT. Its function is to convert VBAT into the front-end voltage required by the system (e.g., 5V front-end voltage). Its output terminal is connected to the detection and comparison module 21 of the overvoltage protection circuit 2 to provide voltage input to the entire overvoltage protection device.

[0045] The input terminal of the overvoltage protection circuit 2 is connected to the output terminal of the power supply regulating module 1, and its output terminal is connected to the microcontroller module 4. It is used to detect whether the 5V power supply voltage converted by the power supply regulating module 1 exceeds the overvoltage protection threshold. If it exceeds the threshold, the power supply to the microcontroller module 4 is cut off, thereby realizing the overvoltage protection function.

[0046] The self-diagnostic circuit 3 is bidirectionally connected to the overvoltage protection circuit 2 and the microcontroller module 4. It is used to diagnose and evaluate the functional status of the overvoltage protection circuit 2 before the entire system is powered on and initialized, so as to ensure its normal operation, improve system reliability and support preventive maintenance.

[0047] The microcontroller module 4 mentioned above is the core component of the entire device. It receives power from the overvoltage protection circuit 2 to operate and is bidirectionally connected to the self-diagnostic circuit 3. It receives signals from the self-diagnostic circuit to determine the operating status of the overvoltage protection device and sends control signals to the self-diagnostic circuit to ensure that the system can complete fault diagnosis and handling functions in overvoltage scenarios.

[0048] Next, continue to refer to Figure 2 and Figure 3 The specific structure of each part of the overvoltage protection device 1 of this utility model will be described.

[0049] like Figure 2 As shown, the overvoltage protection circuit 2 mainly includes a detection comparison module 21 and a power switch module 22, which are used to detect overvoltage and perform the main power supply cut-off action.

[0050] The aforementioned detection and comparison module 21 further includes an overvoltage trigger module 211 and a reference comparator module 212.

[0051] The overvoltage trigger module 211 is the triggering start link for overvoltage detection. It is used to monitor whether the voltage exceeds the overvoltage threshold. Its input terminal receives VCC_5V power supply and over-voltage trigger signal, and its output terminal is connected to the reference comparator module 212.

[0052] The aforementioned reference comparator module 212 uses the bandgap reference as a reference to compare and judge the output of the overvoltage trigger module 211; when it is confirmed that an overvoltage has occurred, it outputs a control signal to the power switch module 22 to achieve precise overvoltage cutoff.

[0053] The power switch module 22 is used to cut off the main power supply to the microcontroller module 4 in case of overvoltage, so as to avoid damage to the microcontroller module 4 by overvoltage. Its input terminal is connected to VCC_5V and the output of the reference comparator module 212, and its output terminal supplies the MCU_5V power supply to the microcontroller module 4.

[0054] The self-diagnostic circuit 3 is arranged in parallel with the overvoltage protection circuit 2, and mainly includes a backup switch module 31 and an analog-to-digital converter module 32, which are used to perform self-diagnosis of the overvoltage protection function of the overvoltage protection device 1.

[0055] The input terminal of the aforementioned backup switch module 31 receives VCC_5V and a backup supply enable signal. Its output terminal is divided into two paths: one path is connected to the input terminal of the microcontroller module 4 via a diode to provide backup power to the microcontroller module 4. When the power switch module is activated, it switches the backup power supply to the MCU to ensure that the MCU can perform diagnostic operations; the other path is connected to the analog-to-digital converter module 32 and supplies the voltage signal of the backup power supply, which is then converted into a digital signal and generates an overvoltage diagnostic signal to determine whether the overvoltage protection circuit is operating normally.

[0056] The input terminal of the aforementioned analog-to-digital converter module 32 is connected to the output of the backup switch module 31 and the MCU, which collects voltage signals and converts them into digital signals, and outputs an over-voltage diagnostic signal to the MCU to analyze the working status of the over-voltage protection device.

[0057] In addition, a diode is connected between the overvoltage protection circuit 2 and the self-diagnostic circuit 3. Specifically, a diode is provided between the output terminal of the power switch module 22 and the output terminal of the backup switch module 31.

[0058] This diode has two functions: first, it can achieve unidirectional conduction to prevent reverse voltage flow and ensure the stability of the circuit power supply logic; second, it can act as a voltage reducer so that the output voltage of the backup power supply can be adapted to the working requirements of the microcontroller (MCU), ensuring that the MCU can be stably powered by the backup power supply when the main power supply is cut off, thereby effectively ensuring the normal execution of functions such as self-diagnosis.

[0059] Next, continue to refer to Figure 3The connection relationship between the various components of the overvoltage protection device of this utility model will be described in more detail.

[0060] More specifically, such as Figure 3 As shown, the output port "VCC_5V" of the power regulation module 1 (DC / DC) is divided into three paths: the first path is connected to the "IN" port of the detection comparison module 21 (REFERENCE AND DETECTION) to input a 5V detection voltage; the second path is connected to the input terminal of the power switch module 22 (OV PROTECTION SWITCH) as the main power source for the microcontroller module 4; and the third path is connected to the input terminal of the backup switch module 31 (BACKUP SUPPLY SWITCH) to provide power input for the backup power supply circuit.

[0061] The "IN" port of the aforementioned detection and comparison module 21 receives the supply voltage from the power regulation module 1, and the "OUT" port is connected to the control terminal of the power switch module 22. The detection and comparison module 21 detects and compares whether the supply voltage exceeds the preset maximum voltage threshold of overvoltage protection. When overvoltage is detected, the signal output from the "OUT" port will flip, thereby controlling the power switch module 22 to cut off, so as to protect the microcontroller module 4 from damage by overvoltage. Its "REF" port (REF_MANIPULATE) is connected to the "OV_TEST_TRIG" port of the analog-to-digital converter module 32 in order to adjust the reference threshold of overvoltage protection.

[0062] The input terminal of the power switch module 22 is connected to the "VCC_5V" port of the power regulation module 1, its control terminal is connected to the "OUT" port of the detection and comparison module 21, and its output terminal is directly connected to the "VCC_5V_PROT" power supply port of the microcontroller module 4.

[0063] The power switch module 22 provides main power to the MCU when no overvoltage is detected; when the "OUT" signal of the comparator module 21 is detected to flip, it cuts off the main power supply to the microcontroller module 4 so as to realize the overvoltage protection function.

[0064] The input terminal of the aforementioned backup switch module 31 is also connected to the "VCC_5V" port of the power conditioning module 1, and its control terminal is connected to the "OV_TEST_BSPL" port of the analog-to-digital converter module 32.

[0065] Before the microcontroller is initialized, the microcontroller controls this module to provide a backup power supply, which is then stepped down by a diode before being supplied to the microcontroller. One of its output terminals is connected to the power supply terminal of the microcontroller module 4 via the aforementioned diode, and the other is connected to the voltage acquisition branch of the analog-to-digital converter module 32. This is used to switch to the backup power supply when the main power supply is cut off and to provide a voltage sampling source to the analog-to-digital converter module 32.

[0066] The “OV_TEST_AD” port of the aforementioned analog-to-digital conversion module 32 is connected to the node between the voltage divider resistor and the grounding component to acquire the power supply voltage signal; the “OV_TEST_BSPL” port is connected to the control terminal of the backup switch module 31 to output the backup power enable control signal; and the “OV_TEST_TRIG” port is connected to the “REF” port of the detection and comparison module 21 to trigger the overvoltage reference adjustment.

[0067] After converting the acquired analog voltage signal into a digital signal, the module outputs an overvoltage diagnostic signal to the microcontroller module 4. The microcontroller determines whether the overvoltage protection circuit is working properly by reading the voltage value of "OV_TEST_AD". The shutdown operation of this diagnostic process is completed by shutting down the detection comparison module 21 and reading back the voltage value of "OV_TEST_AD" to confirm the status.

[0068] The “VCC_5V_PROT” port of the microcontroller module 4 receives power from the power switch module 22 or the backup switch module 31, and at the same time receives the overvoltage diagnostic signal output from the “OV_TEST_AD” port of the analog-to-digital converter module 32, so as to determine the working status of the overvoltage protection device.

[0069] In the self-diagnosis process, the microcontroller actively starts the detection and comparison module 21, causing the "OUT" output signal to flip. At this time, the output of the power switch module 22 is interrupted, and the microcontroller is powered by the voltage output from the backup switch module 31 and stepped down by the diode. Then, the overvoltage protection circuit is diagnosed by the voltage value of "OV_TEST_AD".

[0070] As described above, the overvoltage protection device of this utility model uses low-cost discrete components to replace the integrated PMIC / SBC solution, which can save the cost of high-priced integrated chips and a large number of dedicated external matching components, while simplifying the debugging process and significantly reducing the overall cost of material procurement, R&D debugging and subsequent maintenance.

[0071] It is important to note that, in this context, "discrete" refers to electronic components that are not integrated into a single power management integrated circuit (PMIC) or system base chip (SBC), but rather exist as independent entities. Examples include bandgap reference components, voltage divider resistors, and comparator devices required for the detection and comparison module in overvoltage protection circuits; switching transistors (such as MOSFETs) in power switching modules; and backup switching devices, analog-to-digital converter chips, anti-reverse current diodes, and associated resistors and capacitors in self-diagnostic circuits. These components each possess a single or specific function, allowing for flexible selection and combination based on the voltage specifications and overvoltage protection thresholds of the vehicle power system, without relying on the fixed internal architecture of integrated chips. Furthermore, when a component fails, it can be located and replaced individually without replacing the entire integrated module. This reduces material costs and R&D / debugging complexity, while also improving the convenience of later maintenance. This approach is significantly different from traditional high-cost integrated solutions and better suits the "low-cost, high-flexibility" requirements of low-to-mid-range automotive electronic systems.

[0072] Furthermore, "replaceable" refers to the multiple discrete electronic components that constitute the overvoltage protection circuit (including the bandgap reference element, voltage divider resistor, comparator device in the detection and comparison module, the switching transistor in the power switch module, and the matching resistors and capacitors directly related to the function of the circuit). When a fault occurs or the component parameters need to be changed to adapt to the voltage specifications of different vehicle power systems, it is not necessary to completely disassemble or replace the entire overvoltage protection circuit, nor is it necessary to replace the integrated module (such as the PMIC / SBC in the traditional solution). Only by using conventional circuit testing methods (such as multimeter measurement and oscilloscope troubleshooting) to locate the specific fault or the single / multiple discrete components to be adjusted, the old components can be removed individually and new adaptable components can be installed (such as replacing the switching transistor with the corresponding withstand voltage value and the voltage divider resistor with the corresponding resistance value). Moreover, the replacement process does not affect the normal function of other undamaged components in the circuit, and can quickly restore the working performance of the overvoltage protection circuit.

[0073] Finally, refer to Figure 5 The self-diagnostic process in the overvoltage protection device of this utility model is specifically explained in conjunction with the implementation method of the overvoltage protection and diagnostic circuit.

[0074] like Figure 5 As shown, the overvoltage self-diagnosis process can be roughly divided into seven steps, which are executed sequentially in conjunction with the interactions between the various module ports: Step 1: The process starts in the initial state, and the OV_TEST_BSPL port corresponding to the control terminal OV_TEST_BKPWR of the backup switch module 31 of the self-diagnostic circuit 3 and the OV_TEST_TRIG port corresponding to the REF (REF_MANIPULATE) port of the detection and comparison module 21 of the overvoltage protection circuit 2 are both set to "Disable".

[0075] At this time, the AD_OV_TEST signal acquired by the OV_TEST_AD port of the analog-to-digital converter module 32 should be "low" (LOW) to detect whether there is a short circuit fault in the backup switch module 31. If the signal is not "low", it is determined as "overvoltage self-diagnostic failed, NOK"; if the signal is "low", proceed to the next step. Step 2: Set the OV_TEST_BSPL (i.e. OV_TEST_BKPWR) output from the control terminal of the backup switch module 31 of the self-diagnostic circuit 3 to a high level, set the backup power supply to the "enabled" state (to prevent the microcontroller from being reset during the test), and wait for 3 milliseconds.

[0076] At this time, the power output from the backup switch module 31 supplies power to the VCC_5V_PROT port of the microcontroller module 4 via the diode, and simultaneously provides a signal to the voltage acquisition branch of the analog-to-digital converter module 32.

[0077] Step 3: The AD_OV_TEST signal acquired by the OV_TEST_AD port of the analog-to-digital converter module 32 should be "High". Verify whether the backup switch module 31 has been successfully enabled.

[0078] If the signal is not "high", it is determined as "overvoltage self-diagnosis failed, unqualified"; if the signal is "high", proceed to the next step.

[0079] Step 4: The microcontroller module 4 sets the output of the OV_TEST_TRIG port corresponding to the REF port (REF_MANIPULATE) of the detection and comparison module 21 of the overvoltage protection circuit 2 to "enable", adjusts the overvoltage reference value (used to simulate the overvoltage condition of the DC-DC converter of the power supply regulation module 1), and waits for 3 milliseconds.

[0080] Step 5: The AD_OV_TEST signal acquired by the OV_TEST_AD port of the analog-to-digital converter module 32 should be "Diagnostic" (DIAG), which detects whether the main power supply circuit of the power switch module 22 of the overvoltage protection circuit 2 has been cut off (i.e., whether the power switch module 22 disconnects the main power supply to the MCU due to overvoltage determination).

[0081] If the signal is not "diagnosis", it is determined as "overvoltage self-diagnosis failed, unqualified"; if the signal is "diagnosis", proceed to the next step.

[0082] Step 6: Microcontroller module 4 sets the output of the OV_TEST_TRIG port to "disable" (turns off the overvoltage reference adjustment of detection and comparison module 21), and at the same time sets the output of the OV_TEST_BSPL port to "disable" (disables the backup switch module 31), and waits for 3 milliseconds.

[0083] Step 7: The AD_OV_TEST signal acquired by the OV_TEST_AD port of the analog-to-digital converter module 32 should be "high". After waiting for another 3 milliseconds, the acquired signal should be "low", thereby verifying whether the backup switch module 31 has been successfully turned off.

[0084] If the signal at any stage does not meet expectations, it is judged as "overvoltage self-diagnosis failed, unqualified"; if the signal eventually returns to "to", the entire self-diagnosis process is completed and it is judged as "diagnosis normal" (Diagnostic OK).

[0085] In each branch that is determined to be "unqualified", the corresponding disabling operation (such as disabling OV_TEST_BKPWR, disabling OV_TEST_TRIG, etc.) must be performed and wait for 3 milliseconds before finally ending the diagnostic process.

[0086] Therefore, through the port signal interaction and seven-step software logic coordination between the power regulation module 1, the overvoltage protection circuit 2 (detection and comparison module 21, power switch module 22), the self-diagnosis circuit 3 (backup switch module 31, analog-to-digital conversion module 32) and the microcontroller module 4, a comprehensive self-diagnosis of the overvoltage protection circuit function can be achieved, ensuring its reliability and ASIL-B level functional safety compliance in automotive scenarios.

[0087] (Technical effect) The overvoltage protection device of this invention can significantly reduce costs by using low-cost discrete components to replace integrated PMIC / SBC solutions, saving the cost of expensive integrated chips and a large number of dedicated external matching components. At the same time, it simplifies the debugging process and greatly reduces the overall cost of material procurement, R&D debugging and subsequent maintenance. It is especially suitable for mass application scenarios of low- and mid-end automotive electronic systems.

[0088] In addition, it can effectively improve design flexibility and R&D efficiency. The circuit topology is simple and easy to adjust. It can be flexibly adapted to different MCU models and power supply voltage specifications (such as 5V, 3.3V) without the need to re-optimize a large number of external circuits or software configurations, thus shortening the product development cycle and improving design adaptability.

[0089] This configuration effectively enhances self-diagnostic reliability. The integrated self-diagnostic circuit can proactively assess the functional status of the overvoltage protection circuit before power-on initialization. Combined with the voltage acquisition from the analog-to-digital converter module and the logic judgment of the microcontroller, it enables accurate identification of protection circuit faults, effectively improving system reliability, supporting preventative maintenance strategies, and meeting the diagnostic coverage requirements of ASIL-B functional safety.

[0090] In addition, it can greatly improve the convenience of maintenance. Based on the circuit architecture of discrete components, the fault point can be directly located through conventional testing methods without the need for special debugging tools. When a single component is damaged, it can be replaced in a targeted manner, reducing the difficulty and cost of after-sales maintenance, so as to improve the maintainability of the device.

[0091] In summary, this utility model's overvoltage protection device, while meeting the ASIL-B level functional safety requirements of vehicle electronic systems, solves the shortcomings of existing integrated solutions, such as high cost, complex design, and inconvenient maintenance. It achieves a technological breakthrough of "low cost, high flexibility, high reliability, and easy maintenance," providing a better solution for overvoltage protection and diagnosis of vehicle power supplies, thereby effectively ensuring the safety and economy of vehicle electronic systems.

[0092] It should be understood that this application is not limited to the precise structure described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this application is limited only by the appended claims.

Claims

1. An overvoltage protection device, the overvoltage protection device being applicable to vehicle power supplies, the overvoltage protection device comprising: The power regulation module (1) has its input end connected to the vehicle battery and its output end connected to the overvoltage protection circuit (2), which converts the voltage of the vehicle battery into the front-end voltage of the system and supplies it to the overvoltage protection circuit (2). Overvoltage protection circuit (2), the overvoltage protection circuit (2) detects the front stage voltage, and cuts off the main power supply to the microcontroller module (4) when the front stage voltage exceeds the overvoltage. as well as Microcontroller module (4), which is connected to the output terminal of the overvoltage protection circuit (2) and receives power from the overvoltage protection circuit (2), Its features are, The overvoltage protection circuit (2) consists of multiple replaceable discrete electronic components. It also includes a self-diagnostic circuit (3), which is connected in parallel with the overvoltage protection circuit (2), and its input terminal is connected to the output terminal of the power regulation module (1), for diagnosing the functional status of the overvoltage protection circuit (2). The microcontroller module (4) is also connected to the self-diagnostic circuit (3) to receive the diagnostic signal output by the self-diagnostic circuit (3) and send control signals to the self-diagnostic circuit (3).

2. The overvoltage protection device as described in claim 1, characterized in that, The overvoltage protection circuit (2) includes a detection comparison module (21) and a power switch module (22). The input terminal of the detection comparison module (21) is connected to the output terminal of the power regulation module (1) for detecting the front-end voltage. The input terminal of the power switch module (22) is connected to the output terminal of the power regulation module (1), the control terminal is connected to the output terminal of the detection comparison module (21), and the output terminal is connected to the microcontroller module (4). When an overvoltage is detected, the main power supply to the microcontroller module (4) is cut off.

3. The overvoltage protection device as described in claim 2, characterized in that, The detection and comparison module (21) includes an overvoltage trigger module (211) and a reference comparator module (212). The input terminal of the overvoltage trigger module (211) is connected to the pre-stage voltage and overvoltage trigger signal output by the power supply regulation module (1), and the output terminal is connected to the reference comparator module (212). The reference comparator module (212) uses a bandgap reference as a reference to compare and judge the output of the overvoltage trigger module (211), and outputs a cut-off control signal to the power switch module (22) when an overvoltage is confirmed.

4. The overvoltage protection device as described in claim 3, characterized in that, The input terminal of the power switch module (22) is connected to the pre-amplifier voltage output by the power regulation module (1), and the control terminal receives the level signal output by the detection and comparison module (21). When no overvoltage is detected, the power switch module (22) provides main power to the microcontroller module (4); when it receives the flip-level signal output by the detection comparison module (21), it cuts off the main power supply.

5. The overvoltage protection device as described in claim 1, characterized in that, The self-diagnostic circuit (3) includes a backup switch module (31) and an analog-to-digital converter module (32). The input terminal of the backup switch module (31) is connected to the output terminal of the power regulation module (1), the control terminal is connected to the analog-to-digital converter module (32), and the output terminal is connected to the microcontroller module (4), for providing backup power to the microcontroller module (4). The analog-to-digital converter module (32) is connected to the microcontroller module (4) and the overvoltage protection circuit (2) and is used to collect voltage signals and convert them into digital signals, and output overvoltage diagnostic signals to the microcontroller module (4).

6. The overvoltage protection device as described in claim 5, characterized in that, The output of the backup switch module (31) is divided into two paths: one path is connected to the microcontroller module (4) to provide backup power, and the other path is connected to the voltage acquisition terminal of the analog-to-digital converter module (32) to provide voltage sampling signals to the analog-to-digital converter module (32).

7. The overvoltage protection device as described in claim 5 or 6, characterized in that, A diode is connected in series between the output terminal of the backup switch module (31) and the microcontroller module (4). The diode is used to enable unidirectional conduction to prevent reverse voltage flow and to step down the voltage output from the backup switch module (31) to match the operating voltage requirements of the microcontroller module (4).

8. The overvoltage protection device as described in claim 7, characterized in that, The diode is positioned between the output terminal of the power switch module (22) and the output terminal of the backup switch module (31), with one end connected to the output terminal of the backup switch module (31) and the other end connected to the power supply port of the microcontroller module (4).

9. The overvoltage protection device as described in claim 8, characterized in that, In the self-diagnosis process, the microcontroller module (4) can actively control the detection comparison module (21) to flip the output signal, thereby triggering the power switch module (22) to cut off the main power supply. The microcontroller module (4) is powered by the backup power output from the backup switch module (31), and determines whether the overvoltage protection circuit (2) is normal by reading the voltage value of the port of the analog-to-digital converter module (32).

Images