Braking position switching circuit common LED circuit

Abstract

The utility model discloses an LED circuit shared by a brake position switching circuit. On the original two independent brake and position loops, the brake lamp and the position lamp use different types of LEDs. In combination with the development of an existing automobile, the brake position switching circuit shares an LED circuit, only one LED is needed, the purpose of mutual switching of a brake lamp and a position lamp is achieved through control of a single chip microcomputer, overvoltage and undervoltage protection can be achieved, the cost of the LED is greatly saved, adjustment of various brightness of the LED is better facilitated, and the service life of the brake position switching circuit is prolonged. And the space utilization rate is effectively improved.

Description

Technical Field

[0001] The utility model relates to a combined taillight braking position lamp switching circuit. Background Art

[0002] In the past, automotive lighting lamps included incandescent lamps, halogen lamps, xenon lamps, etc. However, with the continuous expansion of LEDs in the field of vehicle lamps, LEDs can now be found in every position of automotive lighting lamps. The gradual rise of LEDs is closely related to its own excellent characteristics. For example, compared with the incandescent lamps used in automotive lighting lamps in the past, LEDs have significant advantages such as long lifespan, energy conservation, high light quality, simple LED structure, good seismic resistance, fast response speed, small applicable voltage, and small size, allowing for arbitrary transformation of the lamp shape. As people's pursuit of the visual appearance of automobiles becomes higher and higher, the development direction of vehicle lamps also tends towards miniaturization / integration / fineness, and the reuse of LEDs has become a development trend. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is that on the existing two independent braking and position circuits, different types of LEDs are used for the brake lamp and the position lamp.

[0004] To solve the above technical problem, the technical solution of the utility model is to provide a common LED circuit for a braking position switching circuit, characterized in that the position lamp signal input terminal PL+ is connected to the anodes of diode D1 and diode D9, and the brake lamp signal input terminal STOP+ is connected to the anodes of diode D6 and diode D10; the cathodes of diode D1 and diode D6 are connected to one end of capacitor C2, the other end of capacitor C2 is grounded, and a power supply signal VIN is led out from one end of capacitor C2; the power supply signal VIN is respectively connected to the anodes of two series-connected LED lamp bead series circuits, the cathode of one LED lamp bead series circuit is connected to the drain of MOS transistor Q1, and the cathode of the other LED lamp bead series circuit is connected to the drain of MOS transistor Q2. The source of MOS transistor Q1 is grounded via resistor R11, and the source of MOS transistor Q2 is grounded via resistor R12;

[0005] The cathodes of diode D9 and diode D10 are respectively connected to one end of resistor R13 and resistor R14; the other end of resistor R13 is connected to one end of resistor R16 and resistor R17, the other end of resistor R16 is grounded, the other end of resistor R17 is connected to the cathode of zener diode ZD1 and the first AD signal input pin of microcontroller U2, and the anode of zener diode ZD1 is grounded; the other end of resistor R14 is connected to one end of resistor R18 and resistor R15, the other end of resistor R18 is grounded, the other end of resistor R15 is connected to the cathode of zener diode ZD2 and the second AD signal input pin of microcontroller U2, and the anode of zener diode ZD2 is grounded;

[0006] The power supply input pin of the single-chip microcomputer U2 is connected to the power supply output pin of the LDO chip U3, and the power supply input pin of the LDO chip U3 is connected to the power supply signal VIN;

[0007] The first PWM signal output pin of the single-chip microcomputer U2 is connected to one end of the resistor R5. The other end of the resistor R5 is connected to one end of the resistor R9, the capacitor C6, and the resistor R6. The other ends of the resistor R9 and the capacitor C6 are grounded. The other end of the resistor R6 is connected to one end of the capacitor C72 and the input end of the first voltage follower circuit. The output end of the first voltage follower circuit is connected to the gate of the MOS transistor Q1. The second PWM signal output pin of the single-chip microcomputer U2 is connected to one end of the resistor R3. The other end of the resistor R3 is connected to one end of the resistor R10, the capacitor C8, and the resistor R4. The other ends of the resistor R10 and the capacitor C8 are grounded. The other end of the resistor R4 is connected to one end of the capacitor C96 and the input end of the second voltage follower circuit. The output end of the second voltage follower circuit is connected to the gate of the MOS transistor Q2.

[0008] Preferably, one ends of the TVS diode TV1, the capacitor C1, and the resistor R1 are connected to the anode of the diode D1, and the other ends are grounded.

[0009] Preferably, one ends of the TVS diode TV2, the capacitor C4, and the resistor R2 are connected to the anode of the diode D6, and the other ends are grounded.

[0010] Preferably, the power supply input pin of the single-chip microcomputer U2 is grounded after being connected in series with the capacitor C15.

[0011] Preferably, the power supply output pin of the LDO chip U3 is connected to one ends of the capacitor C12 and the capacitor C13, and the other ends of the capacitor C12 and the capacitor C13 are grounded.

[0012] Preferably, the power supply input pin of the LDO chip U3 is connected to the enable signal input pin of the LDO chip U3 via the resistor R19; the power supply input pin of the LDO chip U3 is also connected to one ends of the capacitor C10 and the capacitor C11, and the other ends of the capacitor C10 and the capacitor C11 are grounded.

[0013] Preferably, the first voltage follower circuit includes an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected to the other end of the resistor R6. The inverting input terminal of the operational amplifier U1A is connected to the source electrode of the MOS transistor Q1. The power supply terminal of the operational amplifier U1A is connected to the power supply output pin of the LDO chip U3 and is also connected to the grounded capacitor C3.

[0014] Preferably, the second voltage follower circuit includes an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to the other end of the resistor R4, the inverting input terminal of the operational amplifier U1B is connected to the source electrode of the MOS transistor Q2, and the power supply terminal of the operational amplifier U1B is connected to the power supply output pin of the LDO chip U3 and is also connected to a grounded capacitor C5.

[0015] On the original two independent braking and position circuits, different types of LEDs are used for the brake light and the position light. Combining with the development of existing automobiles, the present invention provides a drive for sharing an LED for the brake and position lights. Only one type of LED is used, and the single-chip microcomputer is used to control to achieve the purpose of mutual switching between the brake light and the position light, and overvoltage and undervoltage protection can be realized, greatly saving the cost of the LED, being more conducive to the adjustment of various brightnesses of the LED, and effectively improving the space utilization rate. Brief Description of the Drawings

[0016] Figure 1 It is a circuit schematic diagram of a circuit for sharing an LED for a brake position switching circuit provided by the present invention. Detailed Embodiment

[0017] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and not to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms also fall within the scope defined by the appended claims of this application.

[0018] A circuit for sharing an LED for a brake position switching circuit disclosed in this embodiment is as Figure 1 shown, and its working principle is described as follows:

[0019] 1. When the power supply is applied to PL+ (position light):

[0020] The first line voltage flows through the TVS diode TV1, the capacitor C1, the resistor R1, the diode D1, and the capacitor C2 to the LED beads D2, D4, D7 and the LED beads D3, D5, D8;

[0021] The second line voltage flows through the diode D10, the resistor R14, the resistor R15, the resistor R18, and the zener diode ZD2 to the 18th pin (AD2 network) of the single-chip microcomputer U2. In this embodiment, the model of the single-chip microcomputer U2 is APM32F003F6U7;

[0022] The third line voltage flows through capacitor C10, capacitor C11, and resistor R19 to provide voltage for the LDO chip U3, enabling the LDO chip U3 to output a 5V power supply to power the microcontroller U2. In this embodiment, the model of the LDO chip U3 is MPQ2019.

[0023] 2. When STOP+ (brake light) is powered:

[0024] The first line voltage flows through the TVS diode TV2, capacitor C4, resistor R2, diode D6, and capacitor C2 to the LED beads D2, D4, D7 and the LED beads D3, D5, D8.

[0025] The second line voltage flows through diode D9, resistor R13, resistor R16, resistor R17, and zener diode ZD1 to pin 20 (AD1 network) of the microcontroller U2.

[0026] The third line voltage flows through capacitor C10, capacitor C11, and resistor R19 to provide voltage for the LDO chip U3, enabling the LDO chip U3 to output a 5V power supply to power the microcontroller U2.

[0027] 3. When PL+ (position light) is powered:

[0028] The first line voltage flows through TV1, C1, R1, D1, C2 to D2 - D4 - D7, D3 - D5 - D8.

[0029] The second line voltage flows through D10, R14, R15, R18, ZD2 to pin 18 (AD2 network) of U2.

[0030] The third line voltage flows through C10, C11, R19 to provide voltage for U3 (LDO), enabling U3 to output 5V to power U2 (microcontroller).

[0031] 4. When STOP+ (brake light) is powered alone:

[0032] After the microcontroller U2 detects the power supply signal, its pin 14 (PWM1) and pin 12 (PWM2) output high levels. After being divided and filtered by resistor R5 and resistor R9, a stable voltage is provided for resistor R6 and resistor R4. Utilizing the "voltage follower characteristic" of operational amplifier U1A and operational amplifier U1B, that is, the voltages between the two input pins of the operational amplifier, pin 3 and pin 2 of U1A and pin 5 and pin 6 of U1B, are equal. When a stable voltage is input to resistor R4 and resistor R6, the voltages across resistor R11 and resistor R12 are also Vin. Therefore, regardless of how the external circuit changes, the current flowing through resistor R7 remains unchanged, achieving the effect of constant current for the brake light.

[0033] 5. When PL+ (position light) is powered alone:

[0034] After the single-chip microcomputer U2 collects the power supply signal, its pin 14 (PWM1) and pin 12 (PWM2) output a duty cycle of 10%. After being divided and filtered by resistor R5 and resistor R9, it provides a stable voltage for resistor R6 and resistor R4. The "voltage follower characteristic" of operational amplifier U1A and operational amplifier U1B is utilized, that is, the voltages between pin 3 and pin 2 of U1A and between pin 5 and pin 6 of U1B, the two input pins of the operational amplifier, are equal to achieve this. When a stable voltage is input to resistor R4 and resistor R6, the voltages across resistor R11 and R12 are also Vin. Therefore, no matter how the external circuit changes, the current flowing through resistor R7 remains unchanged, so as to achieve the effect of constant current for the position lamp.

[0035] 6. When STOP+ (brake lamp) and PL+ (position lamp) are powered on simultaneously, the brake lamp lighting effect is achieved.

[0036] 7. According to Ohm's law, current is equal to voltage divided by resistance. Therefore, the currents flowing through resistor R11 and R12 are: V1 / R11, V2 / R12. Since the voltages across resistor R11 and R12 are always V1 and V2, no matter how the external circuit changes, the currents flowing through resistor R11 and resistor R12 always remain unchanged. Similar to the principle of the triode constant current circuit, the currents of LED lamp beads D2, D4, D7 and LED lamp beads D3, D5, D8 are also equal to the currents of resistor R11 and resistor R12. Therefore, even if the voltages of LED lamp beads D2, D4, D7 and LED lamp beads D3, D5, D8 are variable voltages, the currents of LED lamp beads D2, D4, D7 and LED lamp beads D3, D5, D8 can remain fixed and unchanged, achieving the effect of constant current.

[0037] 8. The normal voltage range of the lamp is 9 - 16V. To prevent damage to the lamp caused by overvoltage or undervoltage input, the present utility model adds an over- and under-voltage protection mechanism. When the voltage is lower than 7.5V or higher than 17V, the 20th pin (AD1) and 18th pin (AD2) of the single-chip microcomputer U2 output low level, and MOS transistors Q1 and Q2 are turned off, and the LED lamp beads go out, so as to achieve the effect of protecting the LED.

Claims

1. A braking position switching circuit sharing an LED circuit, characterized in that, The position lamp signal input terminal PL+ is connected to the anodes of diode D1 and diode D9, and the brake lamp signal input terminal STOP+ is connected to the anodes of diode D6 and diode D10; the cathodes of diode D1 and diode D6 are connected to one end of capacitor C2, the other end of capacitor C2 is grounded, and a power supply signal VIN is led out from one end of capacitor C2; the power supply signal VIN is respectively connected to the anodes of two series-connected LED lamp bead series circuits. The cathode of one LED lamp bead series circuit is connected to the drain of MOS transistor Q1, and the cathode of the other LED lamp bead series circuit is connected to the drain of MOS transistor Q2. The source of MOS transistor Q1 is grounded via resistor R11, and the source of MOS transistor Q2 is grounded via resistor R12; the cathodes of diode D9 and diode D10 are respectively connected to one ends of resistor R13 and resistor R14; the other end of resistor R13 is connected to one ends of resistor R16 and resistor R17. The other end of resistor R16 is grounded, and the other end of resistor R17 is connected to the cathode of zener diode ZD1 and the first AD signal input pin of microcontroller U2, and the anode of zener diode ZD1 is grounded; the other end of resistor R14 is connected to one ends of resistor R18 and resistor R15. The other end of resistor R18 is grounded, and the other end of resistor R15 is connected to the cathode of zener diode ZD2 and the second AD signal input pin of microcontroller U2, and the anode of zener diode ZD2 is grounded; the power supply input pin of microcontroller U2 is connected to the power supply output pin of LDO chip U3, and the power supply input pin of LDO chip U3 is connected to the power supply signal VIN; the first PWM signal output pin of microcontroller U2 is connected to one end of resistor R5, the other end of resistor R5 is connected to one ends of resistor R9, capacitor C6 and resistor R6. The other ends of resistor R9 and capacitor C6 are grounded, and the other end of resistor R6 is connected to one end of capacitor C72 and the input end of the first voltage follower circuit. The output end of the first voltage follower circuit is connected to the gate of MOS transistor Q1; the second PWM signal output pin of microcontroller U2 is connected to one end of resistor R3, the other end of resistor R3 is connected to one ends of resistor R10, capacitor C8 and resistor R4. The other ends of resistor R10 and capacitor C8 are grounded, and the other end of resistor R4 is connected to one end of capacitor C96 and the input end of the second voltage follower circuit. The output end of the second voltage follower circuit is connected to the gate of MOS transistor Q2.

2. The shared LED circuit for a braking position switching circuit as described in claim 1, wherein One ends of TVS diode TV1, capacitor C1 and resistor R1 are connected to the anode of diode D1, and the other ends are grounded.

3. A braking position switching circuit sharing an LED circuit as described in claim 1, characterized in that, One ends of TVS diode TV2, capacitor C4 and resistor R2 are connected to the anode of diode D6, and the other ends are grounded.

4. A braking position switching circuit sharing an LED circuit according to claim 1, characterized in that, The power supply input pin of microcontroller U2 is grounded through capacitor C15 in series.

5. A braking position switching circuit sharing an LED circuit according to claim 1, characterized in that, The power supply output pin of LDO chip U3 is connected to one ends of capacitor C12 and capacitor C13, and the other ends of capacitor C12 and capacitor C13 are grounded.

6. The common LED circuit for a braking position switching circuit according to claim 1, characterized in that, The power supply input pin of the LDO chip U3 is connected to the enable signal input pin of the LDO chip U3 via a resistor R19; the power supply input pin of the LDO chip U3 is also connected to one end of a capacitor C10 and a capacitor C11, and the other ends of the capacitor C10 and the capacitor C11 are grounded.

7. A braking position switching circuit sharing an LED circuit according to claim 1, characterized in that, The first voltage follower circuit includes an operational amplifier U1A. The non-inverting input terminal of the operational amplifier U1A is connected to the other end of the resistor R6, the inverting input terminal of the operational amplifier U1A is connected to the source electrode of the MOS transistor Q1, and the power supply terminal of the operational amplifier U1A is connected to the power supply output pin of the LDO chip U3 and is also connected to a grounded capacitor C3.

8. A braking position switching circuit sharing an LED circuit according to claim 1, characterized in that, The second voltage follower circuit includes an operational amplifier U1B. The non-inverting input terminal of the operational amplifier U1B is connected to the other end of the resistor R4, the inverting input terminal of the operational amplifier U1B is connected to the source electrode of the MOS transistor Q2, and the power supply terminal of the operational amplifier U1B is connected to the power supply output pin of the LDO chip U3 and is also connected to a grounded capacitor C5.

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