Electronic controller with drive overvoltage clamping for inductive loads

Abstract

The utility model belongs to the field of automobile electron technology relates to the electronic controller with drive overvoltage clamping for inductive load, including clamping circuit one, power anti -reversal and power switch circuit, clamping circuit two, overvoltage detection circuit, microcontroller, inductive load drive circuit and its connection, the power anti -reversal and power switch circuit controlled by overvoltage detection circuit divides the power path in the electronic controller into two parts of power supply end and load supply end, and the clamping circuit and device selection of power supply end and load supply end are relatively independent, thus the clamping device of different clamping voltage with smaller power can be used respectively in power supply end and load supply end. By reducing the clamping voltage of load supply end, the device with lower voltage resistance value can be selected in the drive end, the flexibility of device selection scheme is increased, and the controller cost is reduced.

Description

Technical Field

[0001] This utility model relates to the field of automotive electronics technology, and in particular to an electronic controller (i.e., ECU) with drive overvoltage clamping for inductive loads, used for drive power supply overvoltage clamping protection during load shutdown or abnormal power failure. Background Technology

[0002] In vehicle systems, electronic controllers drive inductive loads such as solenoid valves and motors. When the load is turned off, it needs to release the inductive energy it stores. If the controller cannot provide an effective current discharge path, the inductive energy will be fed back to its power supply line, causing overvoltage damage to the internal components of the controller that use the same power supply.

[0003] For driving inductive loads, to avoid overvoltage on the power supply line, power regulators, such as transient voltage suppressor diodes (TVS), are often used to ground along the power supply path. Furthermore, automotive electronic controllers often require reverse connection protection and power switching circuits to provide reverse connection protection against external power input and turn-off control. This circuitry divides the power path of the drive circuit into two parts: the power supply end and the load power supply end. Overvoltage clamping at the power supply end primarily considers suppressing transient high voltage from the external power input to prevent overvoltage damage to power input-related components. Overvoltage clamping at the load power supply end primarily considers adapting the appropriate clamping voltage and clamping power devices based on the specific inductive load's instantaneous power supply energy during turn-off to prevent overvoltage damage to drive-end components.

[0004] The overvoltage conditions and clamping voltage requirements of the power supply side and the load power supply side are often different. The power supply side mainly considers the extreme voltage range of the external power supply, while the load power supply side considers the actual operating voltage range of the load. If only one clamping device is used to deal with the overvoltage of both the power supply input and the load feedback, the selection of clamping device will be limited, and the cost of the solution will be difficult to optimize.

[0005] Common technical solutions include: 1. To adapt to the low clamping voltage requirements of the load power supply, a high-power TVS is selected, which can simultaneously meet the clamping of the power line input voltage and the load feed voltage. This solution has a simple circuit structure, but the cost of high-power clamping devices is relatively high, and the current capability of the power input path needs to be improved accordingly; 2. A low-power TVS with a high clamping voltage is selected at the power input end, which can only clamp small pulses of the power input and has no large current input clamping. At the same time, a higher voltage-rated drive circuit and power devices are selected at the load drive end to allow the devices to withstand the high power supply feed voltage of the load. Due to the use of higher voltage-rated devices, the product cost of this solution also increases.

[0006] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this utility model, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0007] The purpose of this invention is to solve the technical problems existing in the background art. To this end, it provides an electronic controller with drive overvoltage clamping for inductive loads. First, a low-power TVS is used at the power supply end to ensure clamping of the high-voltage small pulse at the power input, protecting the power input-related components. Second, at the load power supply end, the overvoltage clamping circuit and clamping voltage can be specifically designed according to the inductive energy requirements. When the drive power supply overvoltage is caused by the inductive load being turned off, the inductive energy of the load can be effectively discharged, ensuring that the maximum clamping voltage at the load power supply end is within an acceptable range. Furthermore, when the input voltage at the controller power supply end is higher than the clamping voltage of the clamping circuit, the connection between the power supply end and the load power supply end needs to be disconnected to prevent the clamping circuit from being damaged by excessive clamping current due to the overvoltage clamping circuit at the load power supply end clamping the power input. Therefore, the selection of clamping circuits and components at the power supply end and the load power supply end is relatively independent; thus, lower-power clamping devices with different clamping voltages can be used at the power supply end and the load power supply end respectively. By reducing the clamping voltage at the load power supply end, devices with lower withstand voltage values ​​can be selected at the drive end, increasing the flexibility of device selection and further reducing controller costs.

[0008] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0009] An electronic controller with overvoltage clamping for inductive loads includes: clamping circuit one, power reverse protection and power switch circuit, clamping circuit two, overvoltage detection circuit, microcontroller and inductive load drive circuit.

[0010] The input terminal of clamping circuit one is connected to the external power supply of the controller. The output terminal of clamping circuit one is connected to the input terminal one of the power reverse protection and power switch circuit. The output terminal of the power reverse protection and power switch circuit is connected to the input terminal of clamping circuit two and the overvoltage detection circuit. The output terminal one of the overvoltage detection circuit is connected to the input terminal two of the power reverse protection and power switch circuit. The output terminal of clamping circuit two is connected to the input terminal one of the inductive load drive circuit. The output terminal two of the overvoltage detection circuit is connected to the input terminal of the microcontroller. The output terminal of the microcontroller is connected to the input terminal two of the inductive load drive circuit. The output terminal of the inductive load drive circuit is connected to the external inductive load of the controller.

[0011] The following is a further defined technical solution of this utility model: the highest safe operating clamping voltage V1 of the clamping circuit one is greater than or equal to the highest safe operating clamping voltage V2 of the clamping circuit two.

[0012] The following is a further defined technical solution of this utility model: the output terminal of the clamping circuit one serves as the power supply terminal, and the output terminal of the power anti-reverse and power switch circuit serves as the load power supply terminal.

[0013] The overvoltage detection circuit is used to detect the input voltage at the load power supply terminal. When the input voltage at the load power supply terminal is higher than the highest safe operating clamping voltage V2 of the clamping circuit 2, the overvoltage detection circuit outputs a shutdown control signal to the power supply anti-reverse and power switch circuit to disconnect the power supply terminal input.

[0014] When the input voltage at the load power supply terminal is lower than the preset value V3, an output conduction control signal is sent to the power supply anti-reverse and power switch circuit to connect the clamping circuit one at the power supply terminal and the clamping circuit two at the load power supply terminal, wherein V3≤V2.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] This invention designs a clamping circuit 1, a power reverse protection and power switch circuit, a clamping circuit 2, an overvoltage detection circuit, a microcontroller, an inductive load drive circuit, and their interconnections. The power reverse protection and power switch circuit, controlled by the overvoltage detection circuit, divides the power path within the electronic controller into two parts: a power supply end and a load power supply end. The clamping circuits and components for the power supply end and the load power supply end are selected relatively independently. Therefore, clamping devices with lower power and different clamping voltages can be used at the power supply end and the load power supply end, respectively. By reducing the clamping voltage at the load power supply end, devices with lower withstand voltage values ​​can be selected at the drive end, increasing the flexibility of component selection and reducing controller costs. The overvoltage detection circuit directly detects the overvoltage at the load power supply end through hardware circuitry and controls the on / off state of the power reverse protection and power switch circuits, achieving a microsecond overvoltage response and ensuring the timeliness of the voltage clamping effect.

[0017] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a system connection block diagram of the electronic controller in this utility model;

[0020] Figure 2 This is a circuit connection diagram of clamping circuit one and clamping circuit two of this utility model, wherein, Figure 2 The left side shows the circuit connection diagram of clamping circuit one. Figure 2 The right side shows the circuit connection diagram of clamping circuit two;

[0021] Figure 3 This is a circuit connection diagram of the power supply anti-reverse circuit and the power switch circuit in this utility model;

[0022] Figure 4 This is a circuit connection diagram of the overvoltage detection circuit in this utility model;

[0023] Figure 5 This is a circuit connection diagram of the inductive load driving circuit in this utility model. Detailed Implementation

[0024] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0025] This embodiment provides an electronic controller with overvoltage clamping for inductive loads. For example... Figure 1 As shown, the electronic controller includes: a clamping circuit 1 at the power supply end, a power reverse protection and power switch circuit 2, a clamping circuit 2 at the load power supply end 3, an overvoltage detection circuit 4, a microcontroller 5, and an inductive load drive circuit 6.

[0026] Among them, the clamping circuit 1 input is connected to the external power supply of the controller, and the corresponding circuit has the highest clamping voltage V1 for safe operation.

[0027] Among them, the power reverse protection and power switch circuit 2 includes a power reverse protection device and a power switch device. This part divides the power path in the electronic controller into two parts: the power supply end and the load power supply end. Its input is the output of clamping circuit 1, i.e. the power supply end; its output is connected to the input of clamping circuit 3, as the input of the load power supply end, i.e. the load power supply end.

[0028] Among them, the highest clamping voltage V2 for safe operation of clamping circuit 2 3 is V2, and V2≤V1; its output clamped voltage serves as the power supply input for inductive load drive circuit 6.

[0029] The overvoltage detection circuit 4 detects the input voltage at the load power supply terminal. When the voltage is higher than the preset value V2, it outputs a shutdown control signal to the power supply anti-reverse and power switch circuit 2 to disconnect the power supply terminal input. When the voltage is lower than the preset value V3, it outputs a conduction control signal to the power supply anti-reverse and power switch circuit 2 to connect the clamping circuit 1 at the power supply terminal and the clamping circuit 3 at the load power supply terminal. V3 ≤ V2, and the voltage difference between V2 and V3 provides hysteresis control for the on / off switching of the power supply anti-reverse and power switch circuit 2. The overvoltage detection circuit 4 also outputs an overvoltage status signal to the microcontroller 5.

[0030] Among them, the microcontroller 5 outputs a load control signal to the inductive load drive circuit 6. This control signal is a switching signal or a PWM modulation signal. The microcontroller 5 also acquires the overvoltage status output signal of the overvoltage detection circuit 4 and records and responds to overvoltage faults as needed by the system.

[0031] The inductive load drive circuit 6 includes a power switching device, is powered by the clamped voltage output from the clamping circuit 3, and receives control signals from the microcontroller 5 to drive the inductive load.

[0032] Based on the continuous power supply voltage range that the electronic controller may be provided from the outside, Vrating_power_min to Vrating_power_max, and the highest power supply voltage Vin_max that the internal power input circuitry of the electronic controller can withstand, the highest clamping operating voltage V1 of the clamping circuit 1 at the power supply end is determined to satisfy: Vrating_power_max≤V1≤Vin_max. The main function of the clamping circuit 1 at the power supply end is to clamp possible pulse voltage interference higher than Vrating_power_max, ensuring that the internal power input circuitry of the controller is not damaged.

[0033] Based on the voltage range Vfunction_power_min to Vfunction_power_max for the continuous operation of the electronic controller, and the continuous power supply voltage Vdriver_max for the load drive circuit inside the electronic controller, determine the highest clamping operating voltage V2 of clamping circuit 23 at the load power supply end, such that Vfunction_power_max is satisfied. <V2≤Vdirver_max;

[0034] The above clamping voltage values ​​satisfy:

[0035] Vfunction_power_max<V2≤Varting_power_max≤V1≤Vin_max

[0036] wherein, when the external power supply voltage is between Vfunction_power_max and Varting_power_max, the electronic controller is not required to have full functions, but overvoltage damage to internal devices is not allowed;

[0037] For V2<Vrating_power_max≤V1, when the overvoltage detection circuit 4 detects that the voltage of the load power supply terminal is higher than V2, in order to prevent the second clamping circuit 3 at the load power supply terminal from continuously clamping the external power supply of the controller, a turn-off control signal is output to the reverse power protection and power switch circuit 2, for disconnecting the connection between the first clamping circuit 1 at the power supply terminal and the second clamping circuit 3 at the load power supply terminal; when the overvoltage detection circuit 4 detects that the voltage of the load power supply terminal is lower than V3, a turn-on control signal is output to the reverse power protection and power switch circuit 2, for connecting the connection between the first clamping circuit 1 at the power supply terminal and the second clamping circuit 3 at the load power supply terminal, allowing power supply to the load driving terminal through the outside of the controller;

[0038] The overvoltage detection circuit 4 directly detects the overvoltage at the load power supply terminal through a hardware circuit and controls the on-off of the reverse power protection and power switch circuit 2, which can achieve microsecond overvoltage response and ensure the timeliness of the voltage clamping effect; meanwhile, after the overvoltage detection circuit 4 identifies the overvoltage, it outputs an effective overvoltage status signal to the microcontroller 5, so that the microcontroller 5 can identify the fault status and perform fault recording and fault response with low timeliness requirements according to system requirements.

[0039] When the controller operates normally, the microcontroller 5 provides driving control for the inductive load driving circuit 6; when the controller is abnormally powered off, or the microcontroller 5 abnormally turns off the inductive load, the second clamping circuit 3 effectively discharges the inductive energy of the load, ensuring that the maximum clamping voltage at the load power supply terminal is within the acceptable range of the driving circuit.

[0040] Matching components for the second clamping circuit 3 can be selected according to the load current and the magnitude of the inductive energy. In design, appropriately reducing the maximum clamping operating voltage V2 of the second clamping circuit 3 allows the use of components with lower voltage resistance in the inductive load driving circuit 6, thereby improving the flexibility of the solution and reducing the cost of the controller.

[0041] as Figure 2 shown, the first clamping circuit 1 can adopt a bidirectional TVS diode, and the second clamping circuit 3 can adopt a unidirectional TVS diode, and preferably, the maximum overvoltage clamping operating voltage V1 of the first clamping circuit 1 is higher than the maximum overvoltage clamping operating voltage V2 of the second clamping circuit 3.

[0042] as Figure 3 As shown, the power supply reverse protection and power switch circuit 2 can be a series structure of dual NMOS transistors. The driving voltage is provided by the output of the charge pump (i.e., the charge pump drive circuit), and the on and off of the dual NMOS transistors are controlled by the enable signal issued by the overvoltage detection circuit 4.

[0043] like Figure 4 As shown, the overvoltage detection circuit 4 can be constructed from a voltage comparator chip; resistors R1 and R2 form a voltage divider resistor, used to detect the output voltage of the power supply reverse protection and power switch circuit 2, and input it to the negative reference input terminal of the comparator chip; the reference voltage Vref is connected to the positive reference input terminal of the comparator chip through resistor R3 and the signal supply voltage VCC is connected through resistor R4 to provide a hysteresis reference voltage for overvoltage detection; the output of the comparator chip outputs an overvoltage status signal to the microcontroller 5 through resistor R6; the output of the comparator chip outputs an enable control signal to the power supply reverse protection and power switch circuit 2 through resistor R7.

[0044] like Figure 5 As shown, an H-bridge inductive load drive circuit 6 is constructed using NMOS. When the load is turned off or the controller is abnormally powered off, the inductive energy stored in the load can be fed back to the drive power supply terminal through the body diode of the H-bridge power transistor, resulting in an increase in the supply voltage.

[0045] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model in any way. Any person skilled in the art can make many possible variations and modifications to the technical solution of this utility model using the disclosed methods and techniques, or modify it into equivalent embodiments with equivalent changes, without departing from the scope of the technical solution of this utility model. Therefore, all equivalent changes made based on the shape, structure, and principle of this utility model without departing from its technical solution should be covered within the protection scope of this utility model.

Claims

1. Electronic controller with drive overvoltage clamping for inductive loads, characterized in that, include: Clamping circuit 1 (1), power supply reverse protection and power switch circuit (2), clamping circuit 2 (3), overvoltage detection circuit (4), microcontroller (5) and inductive load drive circuit (6); The input terminal of the clamping circuit one (1) is connected to the external power supply of the controller. The output terminal of the clamping circuit one (1) is connected to the input terminal of the power supply anti-reverse and power switch circuit (2). The output terminal of the power supply anti-reverse and power switch circuit (2) is connected to the input terminal of the clamping circuit two (3) and the overvoltage detection circuit (4). The output terminal of the overvoltage detection circuit (4) is connected to the input terminal of the power supply anti-reverse and power switch circuit (2). The output terminal of the clamping circuit two (3) is connected to the input terminal of the inductive load drive circuit (6). The output terminal of the overvoltage detection circuit (4) is connected to the input terminal of the microcontroller (5). The output terminal of the microcontroller (5) is connected to the input terminal of the inductive load drive circuit (6). The output terminal of the inductive load drive circuit (6) is connected to the external inductive load of the controller.

2. Electronic controller with drive overvoltage clamping for inductive loads according to claim 1, characterized in that, The highest safe operating clamping voltage V1 of the clamping circuit one (1) is greater than or equal to the highest safe operating clamping voltage V2 of the clamping circuit two (3).

3. Electronic controller with drive overvoltage clamping for inductive loads according to claim 2, characterized in that, The output terminal of the clamping circuit (1) is used as the power supply terminal, and the output terminal of the power anti-reverse and power switch circuit (2) is used as the load power supply terminal. The overvoltage detection circuit (4) is used to detect the input voltage of the load power supply terminal. When the input voltage of the load power supply terminal is higher than the safe operating maximum clamping voltage V2 of the clamping circuit 2 (3), the overvoltage detection circuit (4) outputs a shutdown control signal to the power supply anti-reverse and power switch circuit (2) to disconnect the power supply terminal input. When the input voltage at the load power supply terminal is lower than the preset value V3, the output conduction control signal is sent to the power supply anti-reverse and power switch circuit (2) to connect the clamping circuit one (1) at the power supply terminal and the clamping circuit two (3) at the load power supply terminal, wherein V3≤V2.

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