Vehicle-mounted control port protection circuit

Abstract

The utility model discloses a vehicle-mounted control port protection circuit, which comprises a protection device and drive circuit, a voltage stabilizing diode D2 and a biasing circuit, the protection device and drive circuit is connected with an input end INPUT, and the biasing circuit is connected with a control end GPIO. According to the utility model, the negative electrode end of the voltage stabilizing diode D2 is connected with the protection device and the driving circuit, when the voltage of the input end INPUT is too high, the protection device and the driving circuit are broken down, and reverse cut-off is carried out through the voltage stabilizing diode D2, so that the rear-end biasing circuit and the control end GPIO are protected. Meanwhile, due to the fact that the voltage-stabilizing diode D2 has the voltage drop characteristic, the driving capacity of the protection device and the driving circuit can be reduced, and therefore the bias circuit is arranged, corresponding bias voltage is introduced, the voltage drop problem caused by the voltage-stabilizing diode D2 is counteracted, and the driving capacity of the protection device and the driving circuit is guaranteed.

Description

Technical Field

[0001] The utility model relates to the technical field of port protection circuits, in particular to a vehicle-mounted control port protection circuit. Background Art

[0002] Device external ports typically incorporate ESD protection devices, such as fuses and voltage regulator diodes, to prevent static electricity or surge damage. However, due to excessive surge energy and delayed ESD discharge, downstream MOSFETs can be damaged, potentially damaging the GPIOs on the control side and the control chip, ultimately leading to unpredictable risks for the entire device.

[0003] Therefore, the existing technology has defects and needs to be improved. Utility Model Content

[0004] The purpose of the utility model is to overcome the deficiencies of the prior art and provide a vehicle-mounted control port protection circuit.

[0005] The technical solution of the present utility model is as follows: A vehicle-mounted control port protection circuit is provided, including: a protection device and a drive circuit, a voltage regulator diode D2 connected to the protection device and the drive circuit, and a bias circuit connected to the voltage regulator diode D2, the protection device and the drive circuit are connected to the input terminal INPUT, the negative terminal of the voltage regulator diode D2 is connected to the protection device and the drive circuit, the positive terminal of the voltage regulator diode D2 is connected to the bias circuit, and the bias circuit is connected to the control terminal GPIO.

[0006] Furthermore, the protection device and driving circuit include: a fuse F1, a voltage-stabilizing diode D1, a MOS transistor Q1, and a resistor R1. One end of the fuse F1 is connected to the input end INPUT, the other end of the fuse F1 is connected to the negative end of the voltage-stabilizing diode D1 and the drain of the MOS transistor Q1, the gate of the MOS transistor Q1 is connected to one end of the resistor R1 and the negative end of the voltage-stabilizing diode D2, and the positive end of the voltage-stabilizing diode D1, the source of the MOS transistor Q1, and the other end of the resistor R1 are grounded respectively.

[0007] Furthermore, the bias circuit includes: a MOS transistor Q2, a MOS transistor Q3, a resistor R2, and a resistor R3. The drain of the MOS transistor Q2 is connected to the positive terminal of the voltage zener diode D2, the source of the MOS transistor Q2 is connected to one end of the resistor R2, the gate of the MOS transistor Q2 is connected to the drain of the MOS transistor Q3 and one end of the resistor R3, the gate of the MOS transistor Q3 is connected to the control terminal GPIO, the other end of the resistor R2 and the other end of the resistor R3 are connected in parallel to the power supply VCC, and the source of the MOS transistor Q3 is grounded.

[0008] Adopting the above solution, the present invention connects the cathode terminal of the voltage-stabilizing diode D2 to the protection device and the drive circuit. When the voltage at the input terminal INPUT is too high, the protection device and the drive circuit are broken down, and the voltage-stabilizing diode D2 is reversely blocked, thereby protecting the back-end bias circuit and the control terminal GPIO. At the same time, due to the inherent voltage drop characteristic of the voltage-stabilizing diode D2, it will reduce the driving capability of the protection device and the drive circuit. Therefore, by providing a bias circuit, a corresponding bias voltage is introduced to offset the voltage drop caused by the voltage-stabilizing diode D2, thereby ensuring the driving capability of the protection device and the drive circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is a circuit connection diagram of the utility model. DETAILED DESCRIPTION

[0010] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0011] See also Figure 1 The utility model provides a vehicle-mounted control port protection circuit, including: a protection device and a drive circuit, a voltage regulator diode D2 connected to the protection device and the drive circuit, and a bias circuit connected to the voltage regulator diode D2. The protection device and the drive circuit are connected to the input terminal INPUT, the cathode terminal of the voltage regulator diode D2 is connected to the protection device and the drive circuit, the anode terminal of the voltage regulator diode D2 is connected to the bias circuit, and the bias circuit is connected to the control terminal GPIO.

[0012] Because Zener diode D2 has a unidirectional conduction characteristic, connecting the cathode of Zener diode D2 to the protection device and drive circuit will cause the protection device and drive circuit to break down when the input voltage is too high, and Zener diode D2 will reversely cut off the circuit, thereby protecting the back-end bias circuit and the control terminal GPIO. At the same time, due to the inherent voltage drop characteristic of Zener diode D2, it will reduce the driving capability of the protection device and drive circuit. Therefore, by providing a bias circuit, it introduces a corresponding bias voltage to offset the voltage drop caused by Zener diode D2, thereby ensuring the driving capability of the protection device and drive circuit.

[0013] The protective device and drive circuit include: a fuse F1, a Zener diode D1, a MOS transistor Q1, and a resistor R1. One end of the fuse F1 is connected to the input terminal INPUT, the other end of the fuse F1 is connected to the cathode terminal of the Zener diode D1 and the drain of the MOS transistor Q1, the gate of the MOS transistor Q1 is connected to one end of the resistor R1 and the cathode terminal of the Zener diode D2, and the positive terminal of the Zener diode D1, the source of the MOS transistor Q1, and the other end of the resistor R1 are grounded. During operation, the fuse F1 and the Zener diode D1 serve as the primary protection, and the MOS transistor Q1 serves as the drive circuit. When the voltage at the input terminal INPUT is too high, the fuse F1 will melt, thereby preventing the excessive energy from damaging the MOS transistor Q1. At the same time, the Zener diode D1 can conduct when a voltage surge occurs, absorbing excess energy and protecting the circuit from damage. When the surge energy is too large and the Zener diode D1 cannot discharge the energy in time, and the fuse F1 has not yet melted due to the high current causing the temperature to rise, the MOS tube Q1 is broken down. The gate voltage of the MOS tube Q1 is much higher than the drain voltage of the MOS tube Q2. The Zener diode D2 is used for reverse cutoff, thereby protecting the back-end MOS tubes Q2 and Q3 and the control terminal GPIO from damage caused by the surge, effectively ensuring the safety of the back-end control chip and effectively reducing the difficulty and cost of maintenance.

[0014] The bias circuit includes: a MOS transistor Q2, a MOS transistor Q3, a resistor R2, and a resistor R3. The drain of the MOS transistor Q2 is connected to the positive terminal of a voltage-stabilizing diode D2, the source of the MOS transistor Q2 is connected to one end of the resistor R2, the gate of the MOS transistor Q2 is connected to the drain of the MOS transistor Q3 and one end of the resistor R3, the gate of the MOS transistor Q3 is connected to a control terminal GPIO, the other ends of the resistors R2 and R3 are connected in parallel to a power supply VCC, and the source of the MOS transistor Q3 is grounded. By introducing the power supply VCC to turn on the MOS transistors Q2 and Q3, the voltage on the positive terminal side of the voltage-stabilizing diode D2 is increased, thereby increasing the gate drive voltage of the MOS transistor Q1 and preventing the voltage-reducing effect of the voltage-stabilizing diode D2 from affecting the drive voltage of the MOS transistor Q1. Furthermore, by providing resistors R2 and R3, the current in the bias circuit is limited, thereby reducing the overall circuit power consumption.

[0015] In summary, the present invention connects the cathode terminal of the voltage-stabilizing diode D2 to the protection device and the drive circuit. When the voltage at the input terminal INPUT is too high, the protection device and the drive circuit are broken down, and the voltage-stabilizing diode D2 is reversely blocked, thereby protecting the back-end bias circuit and the control terminal GPIO. At the same time, due to the inherent voltage drop characteristic of the voltage-stabilizing diode D2, which reduces the driving capability of the protection device and the drive circuit, a bias circuit is provided to introduce a corresponding bias voltage to offset the voltage drop caused by the voltage-stabilizing diode D2, thereby ensuring the driving capability of the protection device and the drive circuit.

[0016] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A vehicle-mounted control port protection circuit, characterized in that: include: A protection device and a driving circuit, a voltage regulator diode D2 connected to the protection device and the driving circuit, and a bias circuit connected to the voltage regulator diode D2, the protection device and the driving circuit are connected to the input terminal INPUT, the negative terminal of the voltage regulator diode D2 is connected to the protection device and the driving circuit, the positive terminal of the voltage regulator diode D2 is connected to the bias circuit, and the bias circuit is connected to the control terminal GPIO.

2. The vehicle-mounted control port protection circuit according to claim 1, characterized in that: The protection device and driving circuit include: a fuse F1, a voltage-stabilizing diode D1, a MOS transistor Q1, and a resistor R1. One end of the fuse F1 is connected to the input end INPUT, the other end of the fuse F1 is connected to the negative end of the voltage-stabilizing diode D1 and the drain of the MOS transistor Q1, the gate of the MOS transistor Q1 is connected to one end of the resistor R1 and the negative end of the voltage-stabilizing diode D2, and the positive end of the voltage-stabilizing diode D1, the source of the MOS transistor Q1, and the other end of the resistor R1 are grounded respectively.

3. The vehicle-mounted control port protection circuit according to claim 1, characterized in that: The bias circuit includes: a MOS transistor Q2, a MOS transistor Q3, a resistor R2, and a resistor R3. The drain of the MOS transistor Q2 is connected to the positive terminal of the voltage stabilizing diode D2, the source of the MOS transistor Q2 is connected to one end of the resistor R2, the gate of the MOS transistor Q2 is connected to the drain of the MOS transistor Q3 and one end of the resistor R3, the gate of the MOS transistor Q3 is connected to the control terminal GPIO, the other end of the resistor R2 and the other end of the resistor R3 are connected in parallel to the power supply VCC, and the source of the MOS transistor Q3 is grounded.

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