Full-on and full-off circuit

Abstract

The utility model discloses a full-on and full-off circuit, which comprises at least one group of LED drive circuits, and is characterized in that the signal sampling ends of all the LED drive circuits are connected on the same signal processing circuit, the output end of the signal processing circuit is connected with a control circuit, and the control circuit controls all the LED drive circuits; the signal processing circuit is provided with a sampling resistor R6, the front end of the sampling resistor R6 is connected with the LED drive circuit, the rear end of the sampling resistor R6 is connected with a high level comparison circuit and a low level comparison circuit, and the output end of the high level comparison circuit and the output end of the low level comparison circuit are connected to the control circuit in parallel. The LED lamp has the beneficial effects that all the LEDs can be turned off at one time under the condition that the LEDs are short-circuited or short-circuited.

Description

Technical Field

[0001] This utility model relates to the field of automotive lighting technology, and in particular to a circuit that allows for both full illumination and full extinguishing. Background Technology

[0002] In the automotive industry, certain warning lights, such as turn signals and high-mounted brake lights, are required by regulations to ensure that all LEDs turn off when one LED malfunctions, whether due to a short circuit or an open circuit. This is to prevent misunderstandings by other vehicles, which could lead them to misjudge the current vehicle's status and thus affect driving safety.

[0003] Currently, such as Figure 1 As shown, patent application CN 202321614748 discloses a circuit for turning off all LEDs when one is turned off. The working principle of this circuit is as follows: When the vehicle headlight LED malfunctions, the resistance of the LED is not connected to the circuit, causing the current flowing through resistor R9 to increase. This increases the source voltage of MOSFET T3, turning on transistor T5. When transistor T5 turns on, transistor T1 also turns on. The power supply port VCC, resistors R1 and R6, and ground form a circuit. The resistance values ​​of resistors R1 and R6 are much smaller than that of resistor R9. Due to the impedance mismatch, the vehicle headlight LED is close to being off, preventing all vehicle headlight circuits 1 from forming a circuit, thus uniformly controlling the turning off of all vehicle headlight LEDs.

[0004] However, the above circuit can only achieve the function of turning off all LEDs when the LEDs are short-circuited. When the LEDs are open-circuited, the current flowing through resistor R9 cannot increase. Moreover, when the LEDs are open-circuited or short-circuited, the bases of transistors T5 or T4 will have two states: when the LEDs are short-circuited, the base voltages of transistors T5 and T4 are high, and when the LEDs are open-circuited, the base voltages of transistors T5 and T4 are low. Therefore, the above circuit is unlikely to achieve the function of turning off all LEDs when the LEDs are open-circuited or short-circuited. Utility Model Content

[0005] The purpose of this invention is to provide a fully lit and fully extinguished circuit that can turn off all LEDs in the event of a short circuit or a single LED short circuit.

[0006] The key to the fully bright and fully dark circuit is that it includes at least one set of LED driver circuits. The signal sampling terminals of all LED driver circuits are connected to the same signal processing circuit. The output terminal of the signal processing circuit is connected to a control circuit, which controls all LED driver circuits.

[0007] The LED driver circuit is equipped with a power supply circuit for the LED lamp group. The power supply circuit for the LED lamp group is equipped with the signal sampling terminal. The signal sampling terminals of all LED driver circuits are connected in parallel to the signal processing circuit.

[0008] The signal processing circuit is provided with a sampling resistor R6. The front end of the sampling resistor R6 is connected to the LED driving circuit, and the rear end of the sampling resistor R6 is connected to a high-level comparison circuit and a low-level comparison circuit. The output terminals of the high-level comparison circuit and the low-level comparison circuit are connected in parallel to the control circuit.

[0009] The control circuit includes a transistor Q3, which is an NPN transistor. The base of transistor Q3 is connected to the output terminals of the high-level comparator circuit and the low-level comparator circuit. The emitter of transistor Q3 is grounded, and the collector of transistor Q3 is connected to the positive power supply VBAT through resistor R5. The collector of transistor Q3 is also connected to the negative terminal of diode D3, and the positive terminal of diode D3 is connected to the control terminal of the LED driver circuit.

[0010] When the LED light group is working normally, the LED driver circuit is working normally, the output terminals of the high-level comparator circuit and the low-level comparator circuit are low-level, the transistor Q3 is cut off, and the LED light group is lit normally.

[0011] When the LED light group is short-circuited, the voltage at the signal sampling terminal of the corresponding LED driver circuit increases, the output of the high-level comparator circuit is high, the output of the low-level comparator circuit is low, the transistor Q3 is turned on, the LED driver circuit is turned off, and all the LED lights are turned off.

[0012] When the LED light group is open-circuited, the voltage at the signal sampling terminal of the corresponding LED driver circuit drops, the voltage UI decreases, the output of the high-level comparator circuit is low, the output of the low-level comparator circuit is high, the transistor Q3 is turned on, the LED driver circuit is cut off, and all the LED lights in the group are turned off.

[0013] Therefore, in the event of a short circuit or a complete short circuit, all LEDs can be turned off simultaneously.

[0014] At the same time, when all LED lights are turned off, the LED driver circuit is controlled to cut off, so that the LEDs are turned off normally, thus avoiding a short circuit in the LED power supply and avoiding the problem of high circuit power consumption.

[0015] Furthermore, the high-level comparison circuit includes a high-level comparator IC1A. The inverting input of the high-level comparator IC1A is connected to a high reference level VH, the non-inverting input of the high-level comparator IC1A is connected to the rear end of the sampling resistor R6, the output of the high-level comparator IC1A is connected to the positive terminal of diode D1, the negative terminal of diode D1 is connected to the base of transistor Q3 via resistor R7, and the output of the high-level comparator IC1A is also connected to the positive power supply VBAT via pull-up resistor R3.

[0016] The low-level comparison circuit includes a low-level comparator IC1B. The inverting input of IC1B is connected to the rear end of the sampling resistor R6, and the non-inverting input is connected to the low reference level VL. The output of IC1B is connected to the positive terminal of diode D2, and the negative terminal of diode D2 is connected to the base of transistor Q3 via resistor R7. The output of IC1B is also connected to the positive power supply VBAT via pull-up resistor R8.

[0017] Furthermore, the LED driving circuit is equipped with a driving transistor Q1, which is an NPN transistor. The base of the driving transistor Q1 is connected to the positive terminal of the diode D3, and the emitter and collector of the driving transistor Q1 are connected in series in the power supply circuit of the LED lamp group.

[0018] The power supply circuit of the LED lamp group is equipped with an LED lamp group. One end of the LED lamp group is connected to the positive power supply VBAT, and the other end of the LED lamp group is connected to the front end of the resistor R2. The rear end of the resistor R2 is connected to the collector of the driving transistor Q1. The front end of the resistor R2 is also connected to the front end of the sampling resistor R6. The emitter of the driving transistor Q1 is grounded through the resistor R4.

[0019] The LED driving circuit also includes a clamp transistor Q2, which is an NPN transistor. The base of the clamp transistor Q2 is connected to the emitter of the driving transistor Q1. The base of the clamp transistor Q2 is also grounded through a capacitor C1. The collector of the clamp transistor Q2 is connected to the base of the driving transistor Q1. The collector of the clamp transistor Q2 is also connected to the positive power supply VBAT through a resistor R1. The emitter of the clamp transistor Q2 is grounded.

[0020] The constant current drive circuit, composed of driving transistor Q1 and clamping transistor Q2, clamps each other, gradually stabilizing the current flowing through the LED group. This ensures a constant current drive for the LED group. When the positive power supply VBAT fluctuates, the current flowing through the LED group remains unchanged, preventing the luminous intensity of the LED group from increasing or decreasing with fluctuations in the input voltage. This maintains stable brightness and uniformity of the LED group, reduces temperature rise, prevents overheating, slows down light decay, and extends its lifespan.

[0021] Furthermore, the LED light group is provided with light-emitting diodes LED1 and LED2. The positive terminal of LED1 is connected to the positive power supply VBAT, the negative terminal of LED1 is connected to the positive terminal of LED2, and the negative terminal of LED2 is connected to the front end of resistor R2.

[0022] The signal sampling terminal can be either the front end of resistor R2 or the rear end of resistor R2.

[0023] Under normal operating conditions, the high reference level VH > the voltage value UI at the back end of the sampling resistor R6 > the low reference level VL.

[0024] When the LED light group is working normally, the LED driver circuit is working normally. The voltage at the inverting input terminal of the high-level comparator IC1A and the voltage at the forward and inverting input terminals of the low-level comparator IC1B are both UI. The voltage values ​​UI, high reference voltage VH, and low reference voltage VL satisfy VH>UI>VL. At this time, the output of the high-level comparator IC1A is low, the output of the low-level comparator IC1B is low, the transistor Q3 is cut off, and the LED light group is lit normally.

[0025] When the LED light group is short-circuited, the voltage at the signal sampling terminal of the corresponding LED driver circuit increases, and the voltage value UI increases accordingly. The voltage values ​​UI, high reference voltage VH, and low reference voltage VL satisfy UI>VH>VL. At this time, the output of high-level comparator IC1A is high, the output of low-level comparator IC1B is low, transistor Q3 is turned on, the control circuit is turned on, the LED driver circuit is turned off, and all LED lights are turned off.

[0026] When the LED lamp group is open-circuited, the voltage at the signal sampling terminal of the corresponding LED driving circuit is pulled down to the ground, the voltage value UI decreases accordingly, and the voltage values of the voltage value UI, the high reference voltage VH, and the low reference voltage VL satisfy UI < VL < VH. At this time, the output of the high-level comparator IC1A is low level, the output of the low-level comparator IC1B is high level, the triode Q3 conducts, the control circuit conducts, the LED driving circuit is cut off, and all the LED lamp groups are turned off.

[0027] Beneficial effects: 1. The utility model can achieve all LEDs being turned off simultaneously when the LEDs are short-circuited or open-circuited. At the same time, when all the LED lamp groups are turned off, the LED driving circuit is controlled to be cut off, so that the LEDs are normally turned off, thus avoiding the situation of short-circuiting the power supply of the LEDs and preventing the problem of large circuit power consumption.

[0028] 2. The utility model forms a constant-current driving circuit through the driving triode Q1 and the current-limiting triode Q2, so as to drive the LED lamp group with constant current. When the power supply voltage fluctuates, the current flowing through the LED lamp group does not change, and the luminous intensity of the LED lamp group will not increase or decrease with the fluctuation of the input voltage. Thus, the brightness of the LED lamp group is kept stable, the brightness and chromaticity of the LED lamp group are made uniform, the temperature rise of the LED lamp group is reduced, the LED lamp group is prevented from overheating, the light decay of the LEDs is delayed, and the service life is extended. Description of the Drawings

[0029] Figure 1 It is a circuit diagram for realizing all LEDs being turned off simultaneously;

[0030] Figure 2 It is a circuit diagram for all-on and all-off. Detailed Embodiment

[0031] The following further details the specific embodiment and working principle of the utility model in conjunction with the drawings.

[0032] As Figure 2 shown, the all-on and all-off circuit includes the first LED driving circuit 1 and the second LED driving circuit 2 with the same structure. The signal sampling terminals of the first LED driving circuit 1 and the second LED driving circuit 2 are connected to the input end of the signal processing circuit 3, and the output end of the signal processing circuit 3 is connected with a control circuit 4, and the control circuit 4 controls the first LED driving circuit 1 and the second LED driving circuit 2;

[0033] The signal processing circuit 3 is provided with a sampling resistor R6. The front end of the sampling resistor R6 is connected to the signal sampling terminal of the first LED driving circuit 1 and the second LED driving circuit 2. The rear end of the sampling resistor R6 is connected to a high-level comparison circuit and a low-level comparison circuit. The output terminals of the high-level comparison circuit and the low-level comparison circuit are connected in parallel to the control circuit 4.

[0034] The control circuit 4 is equipped with a transistor Q3, which is an NPN transistor. The base of the transistor Q3 is connected to the output terminals of the high-level comparator circuit and the low-level comparator circuit. The emitter of the transistor Q3 is grounded, and the collector of the transistor Q3 is connected to the positive power supply VBAT through resistor R5. The collector of the transistor Q3 is also connected to the negative terminal of diode D3, and the positive terminal of diode D3 is connected to the control terminal of the first LED driving circuit 1 and the second LED driving circuit 2.

[0035] The high-level comparison circuit includes a high-level comparator IC1A. The inverting input of IC1A is connected to a high reference level VH, and the non-inverting input is connected to the rear end of the sampling resistor R6. The output of IC1A is connected to the positive terminal of diode D1, and the negative terminal of diode D1 is connected to the base of transistor Q3 via resistor R7. The output of IC1A is also connected to the positive power supply VBAT via pull-up resistor R3. The positive power supply of IC1A is connected to the positive power supply VBAT, and the negative power supply of IC1A is grounded.

[0036] The low-level comparison circuit includes a low-level comparator IC1B. The inverting input of IC1B is connected to the rear end of the sampling resistor R6. The non-inverting input of IC1B is connected to the low reference level VL. The output of IC1B is connected to the positive terminal of diode D2. The negative terminal of diode D2 is connected to the base of transistor Q3 via resistor R7. The output of IC1B is also connected to the positive power supply VBAT via pull-up resistor R8. The positive power supply of IC1B is connected to the positive power supply VBAT, and the negative power supply of IC1B is grounded.

[0037] The high reference level VH > the back-end voltage value UI of the sampling resistor R6 > the low reference level VL.

[0038] The first LED driving circuit 1 is equipped with a driving transistor Q1, which is an NPN transistor. The base of the driving transistor Q1 is connected to the positive terminal of the diode D3. The emitter of the driving transistor Q1 is connected to the rear end of the resistor R2. The front end of the resistor R2 is connected to the negative terminal of the light-emitting diode LED2 in the first LED group. The positive terminal of the light-emitting diode LED2 is connected to the negative terminal of the light-emitting diode LED1. The positive terminal of the light-emitting diode LED1 is connected to the positive power supply VBAT. The front end of the resistor R2 is also connected to the front end of the sampling resistor R6. The emitter of the driving transistor Q1 is grounded through the resistor R4.

[0039] The first LED driving circuit 1 is further provided with a clamping transistor Q2, which is an NPN transistor. The base of the clamping transistor Q2 is connected to the emitter of the driving transistor Q1. The base of the clamping transistor Q2 is also grounded through a capacitor C1. The collector of the clamping transistor Q2 is connected to the base of the driving transistor Q1. The collector of the clamping transistor Q2 is also connected to the positive power supply VBAT through a resistor R1. The emitter of the clamping transistor Q2 is grounded.

[0040] The second LED driving circuit 2 is equipped with a driving transistor Q4, which is an NPN transistor. The base of the driving transistor Q4 is connected to the positive terminal of the diode D3. The emitter of the driving transistor Q4 is connected to the rear end of the resistor R10. The front end of the resistor R10 is connected to the negative terminal of the light-emitting diode LED4 in the second LED group. The positive terminal of the light-emitting diode LED4 is connected to the negative terminal of the light-emitting diode LED3. The positive terminal of the light-emitting diode LED3 is connected to the positive power supply VBAT. The front end of the resistor R10 is also connected to the front end of the sampling resistor R6. The emitter of the driving transistor Q4 is grounded through the resistor R11.

[0041] The second LED driving circuit 2 is further provided with a clamp transistor Q5, which is an NPN transistor. The base of the clamp transistor Q5 is connected to the emitter of the driving transistor Q4. The base of the clamp transistor Q5 is also grounded through capacitor C2. The collector of the clamp transistor Q5 is connected to the base of the driving transistor Q4. The collector of the clamp transistor Q5 is also connected to the positive power supply VBAT through resistor R9. The emitter of the clamp transistor Q5 is grounded.

Claims

1. A fully illuminated and fully extinguished circuit, comprising at least one set of LED driving circuits, characterized in that, The signal sampling terminals of all LED driver circuits are connected to the same signal processing circuit, and the output terminal of the signal processing circuit is connected to a control circuit, which controls all LED driver circuits. The LED driver circuit is equipped with a power supply circuit for the LED lamp group. The power supply circuit for the LED lamp group is equipped with the signal sampling terminal. The signal sampling terminals of all LED driver circuits are connected in parallel to the signal processing circuit. The signal processing circuit is provided with a sampling resistor R6. The front end of the sampling resistor R6 is connected to the LED driving circuit, and the rear end of the sampling resistor R6 is connected to a high-level comparison circuit and a low-level comparison circuit. The output terminals of the high-level comparison circuit and the low-level comparison circuit are connected in parallel to the control circuit. The control circuit includes a transistor Q3, which is an NPN transistor. The base of transistor Q3 is connected to the output terminals of the high-level comparator circuit and the low-level comparator circuit. The emitter of transistor Q3 is grounded, and the collector of transistor Q3 is connected to the positive power supply VBAT through resistor R5. The collector of transistor Q3 is also connected to the negative terminal of diode D3, and the positive terminal of diode D3 is connected to the control terminal of the LED driver circuit.

2. The fully lit / fully extinguished circuit according to claim 1, characterized in that, The high-level comparison circuit includes a high-level comparator IC1A. The inverting input of the high-level comparator IC1A is connected to a high reference level VH, and the non-inverting input of the high-level comparator IC1A is connected to the rear end of the sampling resistor R6. The output of the high-level comparator IC1A is connected to the positive terminal of diode D1, and the negative terminal of diode D1 is connected to the base of transistor Q3 via resistor R7. The output of the high-level comparator IC1A is also connected to the positive power supply VBAT via pull-up resistor R3. The low-level comparison circuit includes a low-level comparator IC1B. The inverting input of IC1B is connected to the rear end of the sampling resistor R6, and the non-inverting input is connected to the low reference level VL. The output of IC1B is connected to the positive terminal of diode D2, and the negative terminal of diode D2 is connected to the base of transistor Q3 via resistor R7. The output of IC1B is also connected to the positive power supply VBAT via pull-up resistor R8.

3. The fully lit / fully extinguished circuit according to claim 2, characterized in that, The LED driving circuit is equipped with a driving transistor Q1, which is an NPN transistor. The base of the driving transistor Q1 is connected to the positive terminal of the diode D3, and the emitter and collector of the driving transistor Q1 are connected in series in the power supply circuit of the LED lamp group. The power supply circuit of the LED lamp group is equipped with an LED lamp group. One end of the LED lamp group is connected to the positive power supply VBAT, and the other end of the LED lamp group is connected to the front end of the resistor R2. The rear end of the resistor R2 is connected to the collector of the driving transistor Q1, and the emitter of the driving transistor Q1 is grounded through the resistor R4. The LED driving circuit also includes a clamp transistor Q2, which is an NPN transistor. The base of the clamp transistor Q2 is connected to the emitter of the driving transistor Q1. The base of the clamp transistor Q2 is also grounded through a capacitor C1. The collector of the clamp transistor Q2 is connected to the base of the driving transistor Q1. The collector of the clamp transistor Q2 is also connected to the positive power supply VBAT through a resistor R1. The emitter of the clamp transistor Q2 is grounded.

4. The fully lit / fully extinguished circuit according to claim 3, characterized in that, The LED light group is provided with LED1 and LED2. The positive terminal of LED1 is connected to the positive power supply VBAT, the negative terminal of LED1 is connected to the positive terminal of LED2, and the negative terminal of LED2 is connected to the front end of resistor R2.

5. The fully lit / fully extinguished circuit according to claim 3, characterized in that, The front end of resistor R2 is the signal sampling terminal.

6. The fully lit / fully extinguished circuit according to claim 3, characterized in that, The rear end of resistor R2 is the signal sampling terminal.

7. The fully lit / fully extinguished circuit according to claim 2, characterized in that, Under normal operating conditions, the high reference level VH > the voltage value UI at the back end of the sampling resistor R6 > the low reference level VL.

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