A control circuit with overcurrent protection function for turn signal lamp

Abstract

The utility model relates to a control circuit with an overcurrent protection function for a turn signal lamp, comprising a single chip microcomputer, a transistor-driven turn signal lamp circuit, an ADC detection module, an overcurrent protection circuit, a turn switch and a turn signal lamp; the single chip microcomputer is connected to the ADC detection module to receive a detection signal sent by the ADC detection module, the single chip microcomputer is connected to the transistor-driven turn signal lamp circuit, the single chip microcomputer outputs a PWM control signal to the transistor-driven turn signal lamp circuit, the overcurrent protection circuit is respectively connected to the transistor-driven turn signal lamp circuit and the ADC detection module to perform overcurrent protection, and the ADC detection module is connected to the turn signal lamp through the turn switch. The utility model can perform switch detection and drive a light bulb to light up, and has an overcurrent protection function for the turn signal lamp control circuit, and can solve the current safety problem of the existing turn signal lamp control circuit.

Description

Technical Field

[0001] The utility model relates to the technical field of electric vehicle turn signal control, in particular to a circuit for input detection, output drive and overcurrent protection. Background Art

[0002] The turn signal control circuit of existing electric vehicles is generally driven by a flasher, and a turn switch is used to select a light bulb to turn on. However, in rainy weather or other harsh environments, once the turn signal is damp or flooded, the current of the drive circuit will increase, and in severe cases, the control circuit will be burned. Utility Model Content

[0003] In view of the above problems, the utility model proposes a control circuit with overcurrent protection function for turn signal lamps. The utility model can perform switch detection and drive the light bulb to light up. The turn signal lamp control circuit with overcurrent protection function can solve the current safety problem of the existing turn signal lamp control circuit.

[0004] The specific technical solutions are as follows:

[0005] A control circuit with a turn signal overcurrent protection function,

[0006] It includes a single-chip microcomputer, a transistor-driven turn signal light circuit, an ADC detection module, an overcurrent protection circuit, a turn switch and a turn signal light; the single-chip microcomputer is connected to the ADC detection module to receive a detection signal sent by the ADC detection module, the single-chip microcomputer is connected to the transistor-driven turn signal light circuit, the single-chip microcomputer outputs a PWM control signal to the transistor-driven turn signal light circuit, the overcurrent protection circuit is respectively connected to the transistor-driven turn signal light circuit and the ADC detection module to perform overcurrent protection, and the ADC detection module is connected to the turn signal light through the turn switch.

[0007] Furthermore, the ADC detection module includes resistors R2, R8, R12, and capacitor C3. One end of R2 is connected to VCC, and the other end is grounded through R8 and R12 in sequence. Capacitor C3 is connected in parallel with R12. The connecting ends of resistors R2 and R8 are connected to the turn signal through the turn switch, and the connecting ends of resistors R8 and R12 are connected to the microcontroller.

[0008] Furthermore, the transistor-driven turn signal circuit includes resistors R1, R3, R4, R5, capacitor C1, and transistors Q1 and Q2, Q1 is a PNP transistor, and Q2 is an NPN transistor; the emitter of Q1 is connected to VCC, the resistor R2 is connected between the emitter and the collector of Q1, the base of Q1 is connected to the collector of the transistor Q2 via the resistor R3, the resistor R3 is connected to VCC via a parallel structure composed of R1 and C1, the emitter of Q2 is grounded, R5 is connected between the emitter and the base of Q2, and the base of Q2 is connected to the single-chip computer via R4.

[0009] Furthermore, the overcurrent protection circuit includes resistors R9, R6, R7, R10, R11, capacitor C2, comparator U1, and transistor Q3; transistor Q3 is an NPN transistor, the collector of Q3 is connected to the base of Q2, the emitter of Q3 is grounded, the base of Q3 is connected to the output end of U1 via resistor R10, the output end of U1 is connected to the 5v power supply via resistor R7, the positive input end of U1 is connected to the 5v power supply via resistor R6, the negative input end of U1 is grounded after being connected to the parallel structure composed of C2 and R11, and the negative input end of U1 is connected to the connecting end of resistors R2 and R8.

[0010] Furthermore, a diode D1 is provided between the resistors R2 and R8; a voltage stabilizing diode DZ1 is provided between the negative input terminal of the comparator U1 and the ground, and a voltage stabilizing diode DZ2 is provided between the resistor R12.

[0011] Beneficial Effects

[0012] 1. Turn signal detection and drive circuit with both software and hardware overcurrent protection functions.

[0013] 2. Real-time ADC voltage acquisition can be used for switch status detection and over-current protection.

[0014] 3. The strobe of the turn signal is driven by the PWM wave output by the microcontroller, and the output is turned off when an abnormal ADC voltage value is collected.

[0015] 4. D1 is used to prevent reverse current inflow; DZ1 and DZ2 are voltage regulators to protect the microcontroller pins.

[0016] 5. The utility model can perform switch detection and drive the light bulb to light up. The turn signal control circuit with overcurrent protection function can solve the current safety problem of the existing turn signal control circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 , action flow chart;

[0018] Figure 2 , schematic diagram of the circuit of the utility model. DETAILED DESCRIPTION

[0019] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments. The embodiments are implemented based on the technical solution of the present invention. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0020] When the steering switch SW1 is turned to the middle and is in the closed state, the voltage collected at the ADC is Voff due to the voltage division of R2, R8, and R12. The MCU detects the Voff value and turns off the PWM output. This Voff value is the steering closing reference value; when the steering switch SW1 is turned to one side, the voltage at the ADC changes to Von due to the built-in bulb and resistor of the turn signal. The MCU detects the Von value and turns on the PWM output. This Von value is the steering opening reference value. When the turn signal is overcurrent due to moisture, the voltage of the 2nd pin of the comparator will be pulled down, making the comparator output high level, driving Q3 to conduct, and turning off the output of Q1 to form hardware overcurrent protection. Moreover, due to moisture, the built-in resistance component of the turn signal is changed. At this time, the value of ADC is not equal to Voff. The MCU judges the abnormality and turns off the PWM output, forming software overcurrent protection.

[0021] With Figure 1 The action flow diagram shown is as follows: Figure 2 This is a specific schematic diagram of the voltage acquisition and driving solution.

[0022] Figure 2 Detailed explanation: R2, R8, R12, C3 and the internal circuit of the turn signal constitute the ADC detection module;

[0023] R1, R3, R4, R5, C1, Q1, and Q2 form a transistor-driven turn signal circuit; R9, R6, R7, R10, R11, C2, U1, and Q3 form an overcurrent protection circuit, and D1 is used to prevent reverse current inflow; DZ1 and DZ2 are voltage regulators to protect the microcontroller pins.

[0024] The ADC detection module includes resistors R2, R8, R12, and capacitor C3. One end of R2 is connected to VCC, and the other end is connected to ground through R8 and R12 in turn. Capacitor C3 is connected in parallel with R12. The connecting ends of resistors R2 and R8 are connected to the turn signal through the turn switch, and the connecting ends of resistors R8 and R12 are connected to the single-chip computer.

[0025] The transistor-driven turn signal light circuit includes resistors R1, R3, R4, R5, capacitor C1, and transistors Q1 and Q2, Q1 is a PNP transistor, and Q2 is an NPN transistor; the emitter of Q1 is connected to VCC, the resistor R2 is connected between the emitter and the collector of Q1, the base of Q1 is connected to the collector of the transistor Q2 via the resistor R3, the resistor R3 is connected to VCC via a parallel structure composed of R1 and C1, the emitter of Q2 is grounded, R5 is connected between the emitter and the base of Q2, and the base of Q2 is connected to the single-chip computer via R4;

[0026] The overcurrent protection circuit includes resistors R9, R6, R7, R10, R11, capacitor C2, comparator U1, and transistor Q3; transistor Q3 is an NPN transistor, the collector of Q3 is connected to the base of Q2, the emitter of Q3 is grounded, the base of Q3 is connected to the output end of U1 via resistor R10, the output end of U1 is connected to the 5v power supply via resistor R7, the positive input end of U1 is connected to the 5v power supply via resistor R6, the negative input end of U1 is grounded after passing through the parallel structure composed of C2 and R11, and the negative input end of U1 is connected to the connecting end of resistors R2 and R8.

Claims

1. A control circuit with a turn signal overcurrent protection function, characterized in that: It includes a single chip microcomputer, a transistor driving turn signal light circuit, an ADC detection module, an overcurrent protection circuit, a turn switch and a turn signal light; The single-chip microcomputer is connected to the ADC detection module to receive the detection signal sent by the ADC detection module. The single-chip microcomputer is connected to the transistor-driven turn signal circuit. The single-chip microcomputer outputs a PWM control signal to the transistor-driven turn signal circuit. The overcurrent protection circuit is respectively connected to the transistor-driven turn signal circuit and the ADC detection module to perform overcurrent protection. The ADC detection module is connected to the turn signal through a turn switch.

2. A control circuit with a turn signal overcurrent protection function according to claim 1, characterized in that: The ADC detection module includes resistors R2, R8, R12, and capacitor C3. One end of R2 is connected to VCC, and the other end is grounded through R8 and R12 in turn. Capacitor C3 is connected in parallel with R12. The connecting ends of resistors R2 and R8 are connected to the turn signal through the turn switch, and the connecting ends of resistors R8 and R12 are connected to the microcontroller.

3. A control circuit with a turn signal overcurrent protection function according to claim 1 or 2, characterized in that: The transistor driven turn signal circuit includes resistors R1, R3, R4, R5, capacitor C1, and transistors Q1 and Q2, Q1 is a PNP transistor, and Q2 is an NPN transistor; the emitter of Q1 is connected to VCC, the resistor R2 is connected between the emitter and the collector of Q1, the base of Q1 is connected to the collector of the transistor Q2 via the resistor R3, the resistor R3 is connected to VCC via the parallel structure composed of R1 and C1, the emitter of Q2 is grounded, R5 is connected between the emitter and the base of Q2, and the base of Q2 is connected to the single chip computer via R4.

4. A control circuit with a turn signal overcurrent protection function according to claim 3, characterized in that: The overcurrent protection circuit includes resistors R9, R6, R7, R10, R11, capacitor C2, comparator U1, and transistor Q3; transistor Q3 is an NPN transistor, the collector of Q3 is connected to the base of Q2, the emitter of Q3 is grounded, the base of Q3 is connected to the output end of U1 via resistor R10, the output end of U1 is connected to the 5v power supply via resistor R7, the positive input end of U1 is connected to the 5v power supply via resistor R6, the negative input end of U1 is grounded after being connected to the parallel structure composed of C2 and R11, and the negative input end of U1 is connected to the connecting end of resistors R2 and R8.

5. A control circuit with a turn signal overcurrent protection function according to claim 4, characterized in that: A diode D1 is also provided between the resistors R2 and R8; a voltage zener diode DZ1 is also provided between the negative input terminal of the comparator U1 and the ground, and a voltage zener diode DZ2 is provided between the resistor R12.

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