Self-recovery overvoltage protection circuit for automobile controller

Abstract

The utility model proposes a self-recovery overvoltage protection circuit for an automobile controller, and the circuit comprises a protection circuit, a first capacitor C1, a second capacitor C2, and a third capacitor C3, one end of the protection circuit is connected with one end of the first capacitor C1, the other end of the first capacitor C1 is grounded, the other end of the protection circuit is connected with a power supply, and the other end of the protection circuit is grounded. One end of the second capacitor C2 and one end of the third capacitor C3 are both connected with the other end of the protection circuit, and the other end of the second capacitor C2 and the other end of the third capacitor C3 are both grounded. According to the utility model, overvoltage protection of the automobile controller circuit is realized by using the protection circuit, the cost performance of the automobile controller overvoltage protection circuit is improved, and the automobile controller overvoltage protection circuit has strong transportability, can be directly used on any automobile controller, improves the development speed and the working efficiency of products, ensures the design robustness and the product quality, and is suitable for popularization and application. And meanwhile, the development time and the development cost of the product are reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile electronics, in particular to a self-recovery overvoltage protection circuit for an automobile controller. Background Art

[0002] The voltage input to the controller during auxiliary starting of the vehicle is too high. The controller is in a steady state at room temperature. Apply 2 times the power supply voltage to the controller input for 1 minute without damaging the controller.

[0003] The car engine starts with the battery. The internal DC resistance of the car battery will change with the ambient temperature and the battery's use environment, and the output capacity will also change. Especially in winter when the temperature is below -25℃, the battery capacity will drop significantly, causing the battery output voltage to drop accordingly. When the car engine starts, the instantaneous current is several times the rated current during normal rotation. The instantaneous voltage of the battery also drops significantly, causing difficulty in starting. It is necessary to use a starting device or another vehicle's battery for jump starting. When jump starting, a voltage twice higher than the normal working voltage will be generated, which will affect or even burn the control module in the vehicle.

[0004] Currently, circuit protection on the market is generally carried out by fuses or logic protection circuits. Fuse protection is not recoverable and is troublesome to replace; logic circuit protection device circuits are complex and costly. To solve the above problems, a protection circuit needs to be built.

[0005] For example, the utility model with the publication number of 201520882967.7 discloses a protection circuit for the whole vehicle controller against reverse connection, surge and overcurrent, including a power supply, a diode D1, a resettable fuse F1, a TVS tube D2 and a load R1. The positive pole of the diode D1 is connected to the positive pole of the power supply, the negative pole of the diode D1 is connected to one end of the resettable fuse F1, the negative pole of the TVS tube D2 is connected between the other end of the resettable fuse F1 and the positive end of the power supply of the load R1, and the positive pole of the TVS tube D2 is connected between the negative pole of the power supply and the negative end of the power supply of the load R1. This utility model is a protection circuit for the whole vehicle controller. When the power supply is reversely connected, the diode D1 is not turned on, and there is no reverse power flowing into the circuit, so the electronic components will not be burned; when there is a pulse voltage spike, the TVS tube D2 can immediately conduct a large current to the ground to protect the electronic components from being damaged; when a short circuit occurs at the load R1 end, the resettable fuse F1 consumes a large current. The triple protection increases the stability and safety of the vehicle. However, the protection circuit proposed in the application has low stability and poor EMC performance.

[0006] For example, the utility model with the publication number of 201820232744.X discloses an RS485 protection circuit, including an RS485 chip, an overvoltage protection circuit, a power management circuit, a first voltage-stabilizing diode, a second voltage-stabilizing diode, a first resettable fuse and a second resettable fuse; the output end of the overvoltage protection circuit is connected to the input end of the power management circuit, the output end of the power management circuit is connected to the voltage end of the RS485 chip, the first input end of the RS485 chip is connected to the first end of the first resettable fuse, the first end of the first resettable fuse is also connected to the cathode of the first voltage-stabilizing diode, and the anode of the first voltage-stabilizing diode is grounded; the second input end of the RS485 chip is connected to the first end of the second resettable fuse, the first end of the second resettable fuse is also connected to the cathode of the second voltage-stabilizing diode, and the anode of the second voltage-stabilizing diode is grounded. This technical solution realizes signal input protection and overvoltage protection of the power supply for the RS485 chip, which is simple and effective. However, the application circuit is relatively complex and the cost is high. Utility Model Content

[0007] In view of the technical problems that the existing protection circuit has a complex structure and a high cost, the utility model proposes a self-recovery overvoltage protection circuit for an automobile controller, which has a simple structure and improves the cost performance of the automobile controller overvoltage protection circuit.

[0008] In order to achieve the above-mentioned purpose, the technical solution of the utility model is implemented as follows: a self-recovering overvoltage protection circuit for an automobile controller, characterized in that it includes a protection circuit, a first capacitor C1 and a voltage stabilizing filter capacitor group, one end of the protection circuit is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is grounded, one end of the protection circuit and one end of the first capacitor C1 are both connected to a power supply, the other end of the protection circuit is connected to one end of the voltage stabilizing filter capacitor group, and the other end of the protection circuit and the other end of the voltage stabilizing filter capacitor group are both grounded.

[0009] The protection circuit includes a first diode D1, a second diode D2 and a resettable fuse F1. The power supply and one end of the first capacitor C1 are connected to the input end of the first diode D1, the output end of the first diode D1 is connected to one end of the resettable fuse F1, the other end of the resettable fuse F1, one end of the second capacitor C2 and one end of the third capacitor C3 are connected to the output end of the second diode D2, and the input end of the second diode D2 is grounded.

[0010] The voltage stabilizing filter capacitor group includes a second capacitor C2 and a third capacitor C3, one end of the second capacitor C2 and one end of the third capacitor C3 are both connected to the other end of the protection circuit, and the other end of the second capacitor C2 and the other end of the third capacitor C3 are both grounded.

[0011] The second diode D2 is a clamping diode.

[0012] The first capacitor C1 is a 100 pF capacitor.

[0013] The third capacitor C3 is a 100 pF capacitor.

[0014] The second capacitor C2 is a 47 uF / 50V capacitor.

[0015] The second diode D2 is a diode with a breakdown voltage of 40.8 V and an Ipp peak of 28.2 A.

[0016] The resettable fuse F1 is a resettable fuse with a holding current of 0.2 A at room temperature and an operating current of less than 14 A.

[0017] The first diode D1 is a diode with a breakdown voltage of 40.8 V and an Ipp peak of 28.2 A.

[0018] The beneficial effects of the utility model are as follows: the application proposes a self-recovering overvoltage protection circuit, which uses the first diode D1 to sort out the current of the power input to prevent the power supply from being reversed. At the same time, the application uses the self-recovering fuse F1 and the second diode D2 to protect the subsequent automotive circuit from overvoltage, and uses the characteristics of the self-recovering fuse F1 and the second diode D2 to achieve self-recovery of the protection circuit after the power supply returns to normal. The application improves the cost-effectiveness of the automotive controller overvoltage protection circuit, and has strong portability. It can be directly used on any automotive controller, which improves the product development speed and work efficiency, ensures the design robustness and product quality, and reduces the product development time and development cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is a structural schematic diagram of the utility model. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] like Figure 1 As shown, a self-recovery overvoltage protection circuit for an automobile controller includes a protection circuit, a first capacitor C1, a second capacitor C2 and a third capacitor C3, one end of the protection circuit is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is grounded, the other end of the protection circuit is connected to a power supply, one end of the second capacitor C2 and one end of the third capacitor C3 are both connected to the other end of the protection circuit, and the other end of the second capacitor C2 and the other end of the third capacitor C3 are both grounded.

[0023] The protection circuit is mainly used to protect the automobile circuit from overvoltage when the input voltage is too high. The first capacitor C1 is mainly used for high-frequency filtering, and the first capacitor C1 uses a 100 pF capacitor. The second capacitor C2 is mainly used for voltage stabilization, and the second capacitor C2 uses a 47 uF / 50V capacitor. The third capacitor C3 is mainly used for high-frequency filtering, and the third capacitor C3 uses a 100 pF capacitor.

[0024] The protection circuit includes a first diode D1, a second diode D2 and a resettable fuse F1. The power supply and one end of the first capacitor C1 are connected to the input end of the first diode D1, the output end of the first diode D1 is connected to one end of the resettable fuse F1, the other end of the resettable fuse F1, one end of the second capacitor C2 and one end of the third capacitor C3 are connected to the output end of the second diode D2, and the input end of the second diode D2 is grounded.

[0025] Among them, the first diode D1 is mainly used to sort out the current of the power input, and at the same time, the diode characteristics are used to protect the automotive circuit to prevent the power supply from being reversed. The second diode D2 is mainly used to clamp the automotive circuit against voltage overvoltage, and the second diode D2 is a clamping diode (TVS tube). The self-recovery fuse F1 is mainly used to prevent abnormal current from passing when the power input is abnormal, thereby protecting the subsequent automotive circuit.

[0026] When in use, the output current of the power supply is filtered at high frequency through the first capacitor C1 to filter out the high frequency harmonics on the input power supply and protect the subsequent circuit from the influence of high frequency harmonics. Subsequently, the first diode D1 is used to sort out the filtered current to prevent the reverse voltage generated at the moment of opening or closing the load from flowing back to the power supply. Subsequently, the current passes through the self-recovery fuse F1, and the self-recovery fuse F1 is used to protect the subsequent automotive circuit from overcurrent, and the second diode D2 is used to clamp the subsequent automotive circuit for overvoltage protection to prevent the subsequent automotive circuit from being damaged due to overvoltage. The voltage after clamping protection is stabilized by the second capacitor C2 to filter out the low frequency harmonics on the input power supply, so that the voltage output to the load is more stable, and the third capacitor C3 is used for high frequency filtering to filter out the high frequency harmonics generated at the moment of opening or closing the load, eliminate the influence of high frequency harmonics on the power supply, and enter the subsequent automotive circuit after filtering. After adding the first capacitor C1, the second capacitor C2 and the third capacitor C3, the stability of the circuit is effectively improved, and the EMC performance of the circuit is improved.

[0027] Specifically, when the power supply is abnormal and outputs a high voltage, the voltage across the second diode D2 increases to the clamping voltage of the second diode D2, and the second diode D2 turns to the on state, absorbing the high voltage and limiting the voltage to a safe voltage value. At the same time, because the second diode D2 turns to the on state, the current value passing through the self-recovery fuse F1 increases rapidly under the action of the high voltage, and the temperature of the self-recovery fuse F1 increases accordingly. Under the action of the overcurrent characteristic, the resistance of the self-recovery fuse F1 increases, thereby blocking the passage of large current and preventing Vcc from increasing, thereby achieving the purpose of protecting the subsequent automotive circuit. When the power supply is normal, the voltage across the second diode D2 is lower than the clamping voltage, and the second diode D2 turns back to the off state, the current value passing through the self-recovery fuse F1 decreases, and the temperature of the self-recovery fuse F1 decreases, and then the resistance of the self-recovery fuse F1 also decreases, and the overvoltage protection circuit returns to a normal state.

[0028] The first diode D1 and the second diode D2 are selected to have a breakdown voltage of 40.8 V and an Ipp peak of 28.2 A. The resettable fuse F1 is selected to have a holding current of 0.2 A at room temperature and an operating current of less than 14 A. When the current passing through the resettable fuse F1 is 14 A, the fuse off time is 1 ms.

[0029] According to the Ipp peak value, the current of this type of diode can rise to 28.2A within 10us when in use, and decrease to 14.1A after 1s, while the current on the self-recovery fuse F1 exceeds 14A, and the fuse is turned off after 1ms. That is, when the input voltage is higher than 40.8V, the overvoltage protection circuit will be turned off within 1ms to prevent abnormal voltage from damaging the car circuit.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A self-recovery overvoltage protection circuit for an automobile controller, characterized in that: It includes a protection circuit, a first capacitor C1 and a voltage stabilizing filter capacitor group, one end of the protection circuit is connected to one end of the first capacitor C1, the other end of the first capacitor C1 is grounded, one end of the protection circuit and one end of the first capacitor C1 are both connected to a power supply, the other end of the protection circuit is connected to one end of the voltage stabilizing filter capacitor group, and the other end of the protection circuit and the other end of the voltage stabilizing filter capacitor group are both grounded.

2. The self-recovery overvoltage protection circuit for automobile controller according to claim 1, characterized in that: The protection circuit includes a first diode D1, a second diode D2 and a resettable fuse F1. The power supply and one end of the first capacitor C1 are connected to the input end of the first diode D1, the output end of the first diode D1 is connected to one end of the resettable fuse F1, the other end of the resettable fuse F1, one end of the second capacitor C2 and one end of the third capacitor C3 are connected to the output end of the second diode D2, and the input end of the second diode D2 is grounded.

3. The self-recovery overvoltage protection circuit for automobile controller according to claim 2, characterized in that: The voltage stabilizing filter capacitor group includes a second capacitor C2 and a third capacitor C3, one end of the second capacitor C2 and one end of the third capacitor C3 are both connected to the other end of the protection circuit, and the other end of the second capacitor C2 and the other end of the third capacitor C3 are both grounded.

4. The self-recovery overvoltage protection circuit for automobile controller according to claim 3, characterized in that: The second diode D2 is a clamping diode.

5. The self-recovery overvoltage protection circuit for automobile controller according to claim 3 or 4, characterized in that: The first capacitor C1 is a 100 pF capacitor.

6. The self-recovery overvoltage protection circuit for automobile controller according to claim 5, characterized in that: The third capacitor C3 is a 100 pF capacitor.

7. The self-recovery overvoltage protection circuit for automobile controller according to claim 6, characterized in that: The second capacitor C2 is a 47 uF / 50V capacitor.

8. The self-recovery overvoltage protection circuit for automobile controller according to claim 7, characterized in that: The second diode D2 is a diode with a breakdown voltage of 40.8 V and an Ipp peak of 28.2 A.

9. The self-recovery overvoltage protection circuit for automobile controller according to claim 8, characterized in that: The resettable fuse F1 is a resettable fuse with a holding current of 0.2 A at room temperature and an operating current of less than 14 A.

10. The self-recovery overvoltage protection circuit for an automobile controller according to claim 8 or 9, characterized in that: The first diode D1 is a diode with a breakdown voltage of 40.8 V and an Ipp peak of 28.2 A.

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