Driving circuit for double-path output LED vehicle lamp

Abstract

The invention discloses a driving circuit for a double-path output LED vehicle lamp. On and off of the two LED lamp sets are controlled by adopting an input MOSFET full-bridge rectifier circuit, a diode signal rectifier bridge and an output circuit of the LED lamp sets, the MOSFET full-bridge rectifier circuit integrates an existing MOSFET non-polarity reverse connection circuit, the circuit is simplified, meanwhile, an anti-interference first-stage triode control circuit is added, the applicability is wider, and use is more convenient; in addition, non-polarity can be achieved through the input bridge rectifier module, a user does not need to worry that a lamp is not turned on or automobile fuses are burnt out due to reverse insertion, and an original automobile is not damaged. The driving circuit is suitable for driving the double-path output LED car lamp, the LED car lamp is prevented from being damaged after input end signals are reversely connected, and meanwhile two paths of LED car lamp selection output are provided.

Description

Technical Field

[0001] The invention relates to the technical field of an anti-reverse connection driving circuit for an LED vehicle lamp, and in particular to a driving circuit for a dual-path output LED vehicle lamp. Background Art

[0002] More and more motor vehicle lights use light-emitting diodes as light sources. In order to prevent damage to electronic equipment, an anti-reverse connection circuit is usually added to the driving circuit of the LED headlight. The existing two-way LED headlight input technology solution: each group of inputs is assigned an anti-reverse connection circuit. The anti-reverse connection circuit can be implemented through a diode, an uncontrolled rectifier bridge or a MOSFET, but all of them have defects to varying degrees.

[0003] like Figure 1 The figure shows a non-polarity anti-reverse connection circuit using a diode or an uncontrolled rectifier bridge. The prior art has the following problems: a. If a rectifier diode is used as the diode, the on-state voltage drop is large, the power consumption is large, the heat generation is large, and the efficiency of the product is reduced; b. If a Schottky diode is used as the diode, although the on-state voltage is smaller, the unidirectional conductivity deteriorates after the temperature rises, affecting the function of the product.

[0004] like Figure 2 The figure shows a non-polarity anti-reverse connection circuit for MOSFET. The MOSFET circuit can realize the non-polarity anti-reverse connection function for two input terminals, but two sets of such circuits are required to correspond to the two input power supply circuits respectively, and the anti-reverse connection circuit structure is relatively complicated.

[0005] The Chinese invention patent with the publication number CN215187489U discloses a non-polarity dual-color LED decoding car light circuit with integrated daytime running lights and turn signals. The LED lights are driven by adopting a high-power daytime running white light buck constant current module and a turn yellow light buck constant current drive module. At the same time, in the yellow light buck constant current drive module, different powers can be set by replacing and adjusting the constant current sampling resistor to adapt to different decoding models. No external resistor decoding is required, which has wider applicability and is more convenient to use. Moreover, in this application, non-polarity can be achieved by inputting a rectifier bridge module, so there is no need to worry about the light not turning on due to reverse insertion or burning out the car fuse, and there is no damage to the original car. Although this technical solution adopts a non-polarity design, the circuit structure is complex and does not involve the dual output route selection of LED car lights.

[0006] In view of this, the present application aims to make improvements on the existing technology, realize non-polarity input on the three input terminals of the dual-output LED car, prevent the LED lights from being damaged after the input terminal signal is reversed, and realize the selection of the output circuit through the diode signal rectifier bridge and the switching circuit to control the lighting and extinguishing of different automatic LEDs. Summary of the invention

[0007] The purpose of the present invention is to provide a driving circuit for a dual-output LED lamp, so as to prevent the LED lamp from being damaged after the input terminal signal is reversely connected, and at the same time provide two-way LED lamp selection output.

[0008] To achieve the above-mentioned purpose, the present invention provides a driving circuit for a dual-output LED headlight, comprising: an input MOSFET full-bridge rectifier circuit, including a triode control circuit, an upper bridge arm circuit and a lower bridge arm circuit connected to a VIN1 input terminal, an upper bridge arm circuit and a lower bridge arm circuit connected to a VIN2 input terminal, and an upper bridge arm circuit and a lower bridge arm circuit connected to a VIN3 input terminal, the triode control circuit being connected to the lower bridge arm circuits of the three input terminals respectively, so as to prevent the lower bridge arm controlled by the floating terminal from being misconnected; a diode signal rectifier bridge, wherein the input terminal is connected to a switch circuit of an upper bridge arm circuit connected to the VIN2 input terminal and a switch circuit of a lower bridge arm circuit connected to the VIN3 input terminal, and the output terminal of the diode signal rectifier bridge is connected to a first LED headlight group output circuit and a second LED headlight group output circuit.

[0009] According to an embodiment of the present application, the transistor control circuit includes a transistor Q9, a transistor Q10 and a transistor Q12, the emitter of the transistor Q9 is connected to the positive pole of the power supply, the collector of the transistor Q9 is connected to the lower bridge arm circuit connected to the VIN1 input terminal, and the base of the transistor Q9 is connected to the parallel resistors R6 and R7; the emitter of the transistor Q10 is connected to the positive pole of the power supply, the collector of the transistor Q9 is connected to the lower bridge arm circuit connected to the VIN2 input terminal, and the base of the transistor Q9 is connected to the parallel resistors R13 and R14; the emitter of the transistor Q12 is connected to the positive pole of the power supply, the collector of the transistor Q12 is connected to the lower bridge arm circuit connected to the VIN3 input terminal, and the base of the transistor Q12 is connected to the parallel resistors R30 and R21.

[0010] According to an embodiment of the present application, any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the positive terminal of the power supply, the corresponding upper bridge arm switch circuit is turned on, and the corresponding lower bridge arm switch circuit is turned off.

[0011] According to an embodiment of the present application, any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the negative end of the power supply, the corresponding upper bridge arm switch circuit is cut off, and the corresponding lower bridge arm switch circuit is turned on.

[0012] According to an embodiment of the present application, the switch circuits of the upper bridge arm and the lower bridge arm corresponding to the terminal of any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal that is not connected to the input power supply are turned off.

[0013] According to an embodiment of the present application, the VIN1 input terminal is connected to the positive pole of the power supply, the VIN2 input terminal is connected to the negative pole of the power supply, and the current flow path is VIN1 input terminal, upper bridge arm Q1, load, transistor Q9, and VIN2 input terminal in sequence.

[0014] According to an embodiment of the present application, the diode signal rectifier bridge includes a diode D1 capable of preventing reverse connection, and the diode D1 is connected in parallel with an adjusting resistor R4 capable of adjusting a set current value.

[0015] According to an embodiment of the present application, the first LED headlight group and the second LED headlight group are composed of a plurality of LED lamp beads connected in series or in parallel.

[0016] According to an embodiment of the present application, the first LED light group output circuit is provided with a transistor Q15, one end of the transistor Q15 is connected to the first LED light group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of the parallel resistor R28.

[0017] According to an embodiment of the present application, the second LED light group output circuit is provided with a transistor Q14, one end of the transistor Q14 is connected to the second LED light group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of the parallel resistor R26.

[0018] The beneficial effects of the technical solution of the present invention compared with the prior art are:

[0019] 1. This application adopts an input MOSFET full-bridge rectifier circuit. In the full-bridge rectifier circuit, there are 6 bridge arms of the full-bridge rectifier circuit. The existing 2 groups of separate power supply circuits are integrated into a whole. The 4 input terminals of the 2 groups are reduced to three input terminals, and one input terminal is shared, which simplifies the circuit. The dual-channel output LED car can realize 3 input terminals to achieve non-polarity input, thereby improving the convenience of car light application.

[0020] 2. Add a transistor switching circuit to the upper and lower arms of the input rectifier bridge. The switch circuit of the upper arm enables a single end to directly control the conduction of a single upper arm; the transistor control circuit added to the lower arm control circuit prevents the lower arm controlled by the floating end from being mis-conducted.

[0021] 3. The output circuit is selected through the diode signal rectifier bridge and the switching circuit to control the lighting and extinguishing of different automatic LEDs. The lighting and extinguishing logic of the output LED is automatically selected according to the port connected to the power input.

[0022] 4. Compared with the diode rectifier bridge, the MOSFET tube voltage drop is smaller. The diode rectifier bridge voltage drop of two diodes is about 2x0.7V=1.4V, and the MOSFET voltage drop is about 2*0,3V=0.6V.

[0023] 5. In this application, polarity-free can be achieved by inputting a rectifier bridge module, so there is no need to worry about the light not turning on due to reverse insertion or burning out the car fuse, and there is no damage to the original car. It has the advantages of wider applicability, convenient use and no damage to the original car, and solves the problem that the current modification of LED lights requires an external decoder. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of a diode / rectifier bridge non-polarity reverse connection circuit in the prior art;

[0025] Figure 2 It is a schematic diagram of a non-polarity reverse connection circuit of a MOSFET in the prior art;

[0026] Figure 3 The figure is a hardware circuit diagram of a driving circuit for a dual-output LED vehicle lamp according to an example of the present invention. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments. The following embodiments are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0028] See also Figure 3 As shown, a driving circuit for a dual-output LED lamp is shown, comprising Figure 3 In the left box, enter the MOSFET full-bridge rectifier circuit and Figure 3 The diode signal rectifier bridge and output circuit in the right frame, Figure 3 According to the power supply selection of the three input terminals, the switching circuits of the upper bridge arm circuit and the lower bridge arm circuit in the input MOSFET full-bridge rectifier circuit select the lighting and extinguishing logic of the output LED. Compared with the diode rectifier bridge in the prior art, the MOSFET voltage drop of the present application is small, and the four input terminals of the two groups in the MOSFET non-polarity reverse connection circuit are reduced to three input terminals, and one input terminal is shared, which improves the convenience of car light application.

[0029] In this embodiment, the input MOSFET full-bridge rectifier circuit includes a transistor control circuit, an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN1 input terminal, an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN2 input terminal, and an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN3 input terminal. The transistor control circuit is respectively connected to the lower bridge arm circuits of the three input terminals to prevent the lower bridge arm controlled by the floating terminal from being misconnected.

[0030] Specifically, Figure 3As shown, in the full-bridge rectifier circuit, Q1~Q6 are the bridge arms of the full-bridge rectifier circuit, among which Q1, Q3 and Q5 are the upper bridge arms, and Q2, Q4 and Q6 are the lower bridge arms. In the application, the input voltage is applied to two terminals among the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal. When any terminal is connected to the positive terminal of the high power supply, the corresponding upper bridge arm MOSFET is turned on and the lower bridge arm MOSFET is turned off; when any terminal is connected to the negative terminal of the high power supply, the corresponding upper bridge arm MOSFET is turned off and the lower bridge arm MOSFET is turned on; the upper bridge arm and the lower bridge arm corresponding to the terminal not connected to the input power supply are turned off. For example: if the VIN1 input terminal is connected to the positive pole of the power supply and the VIN3 input terminal is connected to the negative pole of the power supply, then Q1 and Q6 are turned on, and Q2, Q3, Q4, and Q5 are all turned off.

[0031] Specifically, the VIN1 input end is connected to the upper bridge arm of Q1 and the lower bridge arm of Q2, the upper bridge arm of Q1 is connected to one end of the resistor R1, and the lower bridge arm of Q2 is connected to one end of the resistor R5; the VIN2 input end is connected to the upper bridge arm of Q3 and the lower bridge arm of Q4, the upper bridge arm of Q3 is connected to one end of the resistor R10, and the lower bridge arm of Q4 is connected to one end of the resistor R11; the VIN3 input end is connected to the upper bridge arm of Q5 and the lower bridge arm of Q6, the upper bridge arm of Q5 is connected to one end of the resistor R11, and the lower bridge arm of Q6 is connected to one end of the resistor R18.

[0032] Specifically, the transistor control circuit includes transistor Q9, transistor Q10 and transistor Q12. The emitter of transistor Q9 is connected to the positive pole of the power supply, the collector of transistor Q9 is connected to the lower bridge arm circuit connected to the input terminal of VIN1, and the base of transistor Q9 is connected to the parallel resistors R6 and R7; the emitter of transistor Q10 is connected to the positive pole of the power supply, the collector of transistor Q9 is connected to the lower bridge arm circuit connected to the input terminal of VIN2, and the base of transistor Q9 is connected to the parallel resistors R13 and R14; the emitter of transistor Q12 is connected to the positive pole of the power supply, the collector of transistor Q12 is connected to the lower bridge arm circuit connected to the input terminal of VIN3, and the base of transistor Q12 is connected to the parallel resistors R30 and R21. Figure 2 By comparing with the prior art, it can be seen that a first-stage transistor control circuit is added to the full-bridge rectifier circuit of the present application. The main function of this stage of circuit is to isolate the output of the rectifier circuit to prevent the output voltage of the rectifier circuit from generating interference signals between different bridge arms, thereby affecting the output selection of the first LED car light group output circuit or the second LED car light group output circuit.

[0033] Specifically, if any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the positive terminal of the high power supply, the corresponding upper bridge arm switch circuit is turned on, and the corresponding lower bridge arm switch circuit is turned off; if any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the negative terminal of the high power supply, the corresponding upper bridge arm switch circuit is turned off, and the corresponding lower bridge arm switch circuit is turned on; if any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is not connected to the input power supply, the corresponding upper bridge arm and lower bridge arm switch circuits are turned off.

[0034] Specifically, the VIN1 input terminal is connected to the positive pole of the power supply, the VIN2 input terminal is connected to the negative pole of the power supply, and the current flow path is the VIN1 input terminal, the upper bridge arm Q1, the load, the transistor Q9, and the VIN2 input terminal in sequence.

[0035] In this embodiment, the input end of the diode signal rectifier bridge is connected to the switching circuit of the upper bridge arm circuit, the input end of VIN2 is connected to the switching circuit of the upper bridge arm circuit, and the input end of VIN3 is connected to the switching circuit of the lower bridge arm circuit, and the output end of the diode signal rectifier bridge is connected to the output circuit of the first LED light group and the output circuit of the second LED light group.

[0036] Specifically, the diode signal rectifier bridge includes a diode D1 capable of preventing reverse connection, and the diode D1 is connected in parallel with an adjusting resistor R4 capable of adjusting a set current value.

[0037] Specifically, the first LED light group and the second LED light group are composed of a plurality of LED lamp beads connected in series or in parallel. Figure 3 As shown, the first LED light group consists of LED1, LED2 and LED3, and the second LED light group consists of LED4, LED5 and LED6.

[0038] Specifically, the output circuit of the first LED light group is provided with a transistor Q15, one end of the transistor Q15 is connected to the first LED light group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of the parallel resistor R28.

[0039] Specifically, the second LED light group output circuit is provided with a transistor Q14, one end of the transistor Q14 is connected to the second LED light group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of the parallel resistor R26.

[0040] Example 1

[0041] a. Working process of full-bridge rectifier circuit:

[0042] The VIN1 input terminal is connected to the +12V of the power supply, the VIN2 input terminal is connected to the negative pole of the power supply, the lower bridge arm of Q7 is turned on, the PIN1 of the upper bridge arm of Q1 is pulled low, the upper bridge arm of Q1 is turned on, and the voltage of point A is 11.6V. The E pole of transistor Q9 is 11.6V, and the B pole of transistor Q9 is low level, then transistor Q9 is turned on, the PIN1 of the lower bridge arm of Q4 is high level, and the lower bridge arm of Q4 is turned on; the current flow path is VIN1 input terminal, upper bridge arm Q1, load, transistor Q9, and VIN2 input terminal. The upper bridge arm is turned on, the voltage of point A is 11.6V, the VIN3 input terminal is floating, then the transistor Q12 is turned off, the PIN1 of the lower bridge arm of Q6 is low level, the lower bridge arm of Q6 is turned off, and the diode D1 has no output. If there is no control circuit at the level of Q9, Q10, and Q12, when the working voltage is applied to any two input terminals, the lower bridge arm corresponding to the floating end will also be turned on. If this floating lower bridge arm is Q4 or Q6, D1 will malfunction and cause the wrong LED to light up.

[0043] b. Output selection circuit

[0044] 1) When the input voltage is applied to the VIN2 input terminal and the VIN3 input terminal at the same time, the diode D1 rectifier bridge is turned on and outputs a high level, the transistor Q13 is turned on, the PIN1 of the transistor Q14 is a high level, the transistor Q14 is turned on, the PIN1 of the transistor Q15 is a low level, the transistor Q15 is cut off, the LED light group of the first LED light group output circuit (0UPUT1 path) is off, and the LED light group of the second LED light group output circuit (0UTPUT2 path) is on.

[0045] 2) On the contrary, when the input voltage is only applied to one of the VIN2 input terminal and the VIN3 input terminal, the diode D1 rectifier bridge is not conducting, the transistor Q13 is cut off, the PIN1 of the transistor Q14 is at a low level, the transistor Q14 is cut off, the PIN1 of the transistor Q15 is at a high level, the transistor Q15 is turned on, the LED light on the output circuit of the first LED light group (OUPUT1 path) is on, and the LED light on the output circuit of the second LED light group (OUTPUT2 path) is off.

[0046] In a driving circuit for a dual-output LED lamp, only one set of LED lamps is lit at the same time. In such an application scenario, the output logic relationship is as shown in Table 1:

[0047] Table 1

[0048]

[0049] In summary, the technical solution of the present application has the following beneficial effects:

[0050] 1. This application adopts an input MOSFET full-bridge rectifier circuit. In the full-bridge rectifier circuit, there are 6 bridge arms of the full-bridge rectifier circuit. The existing 2 groups of separate power supply circuits are integrated into a whole. The 4 input terminals of the 2 groups are reduced to three input terminals, and one input terminal is shared, which simplifies the circuit. The dual-channel output LED car can realize 3 input terminals to achieve non-polarity input, thereby improving the convenience of car light application.

[0051] 2. Add a transistor switching circuit to the upper and lower arms of the input rectifier bridge. The switch circuit of the upper arm enables a single end to directly control the conduction of a single upper arm; the transistor control circuit added to the lower arm control circuit prevents the lower arm controlled by the floating end from being mis-conducted.

[0052] 3. The output circuit is selected through the diode signal rectifier bridge and the switching circuit to control the lighting and extinguishing of different automatic LEDs. The lighting and extinguishing logic of the output LED is automatically selected according to the port connected to the power input.

[0053] 4. Compared with the diode rectifier bridge, the MOSFET tube voltage drop is smaller. The diode rectifier bridge voltage drop of two diodes is about 2x0.7V=1.4V, and the MOSFET voltage drop is about 2*0,3V=0.6V.

[0054] 5. In this application, polarity-free can be achieved by inputting a rectifier bridge module, so there is no need to worry about the light not turning on due to reverse insertion or burning out the car fuse, and there is no damage to the original car. It has the advantages of wider applicability, convenient use and no damage to the original car, and solves the problem that the current modification of LED lights requires an external decoder.

[0055] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A driving circuit for a dual-output LED vehicle lamp, characterized in that: include: An input MOSFET full-bridge rectifier circuit includes a transistor control circuit, an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN1 input terminal, an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN2 input terminal, and an upper bridge arm circuit and a lower bridge arm circuit connected to the VIN3 input terminal. The transistor control circuit is respectively connected to the lower bridge arm circuits of the three input terminals to prevent the lower bridge arm controlled by the floating terminal from being mis-conducted; A diode signal rectifier bridge, the input end of which is connected to the switching circuit of the upper bridge arm circuit, the input end of which is connected to the switching circuit of the lower bridge arm circuit, and the output end of which is connected to the output circuit of the first LED headlight group and the output circuit of the second LED headlight group.

2. A driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The transistor control circuit includes a transistor Q9, a transistor Q10 and a transistor Q12, wherein the emitter of the transistor Q9 is connected to the positive electrode of the power supply, the collector of the transistor Q9 is connected to the lower bridge arm circuit connected to the VIN1 input terminal, and the base of the transistor Q9 is connected to parallel resistors R6 and R7; the emitter of the transistor Q10 is connected to the positive electrode of the power supply, the collector of the transistor Q9 is connected to the lower bridge arm circuit connected to the VIN2 input terminal, and the base of the transistor Q9 is connected to parallel resistors R13 and R14; the emitter of the transistor Q12 is connected to the positive electrode of the power supply, the collector of the transistor Q12 is connected to the lower bridge arm circuit connected to the VIN3 input terminal, and the base of the transistor Q12 is connected to parallel resistors R30 and R21.

3. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: When any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the positive terminal of the power supply, the corresponding upper bridge arm switch circuit is turned on, and the corresponding lower bridge arm switch circuit is turned off.

4. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: When any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal is connected to the negative terminal of the power supply, the corresponding upper bridge arm switch circuit is turned off, and the corresponding lower bridge arm switch circuit is turned on.

5. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The switch circuits of the upper bridge arm and the lower bridge arm corresponding to the terminal of any one of the VIN1 input terminal, the VIN2 input terminal and the VIN3 input terminal that is not connected to the input power supply are turned off.

6. A driving circuit for a dual-output LED vehicle lamp according to claim 2, characterized in that: The VIN1 input terminal is connected to the positive pole of the power supply, the VIN2 input terminal is connected to the negative pole of the power supply, and the current flow path is VIN1 input terminal, upper bridge arm Q1, load, transistor Q9, and VIN2 input terminal in sequence.

7. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The diode signal rectifier bridge includes a diode D1 capable of preventing reverse connection, and the diode D1 is connected in parallel with an adjusting resistor R4 capable of adjusting a set current value.

8. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The first LED headlight group and the second LED headlight group are composed of a plurality of LED lamp beads connected in series or in parallel.

9. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The first LED headlight group output circuit is provided with a transistor Q15, one end of the transistor Q15 is connected to the first LED headlight group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of a parallel resistor R28.

10. The driving circuit for a dual-output LED vehicle lamp according to claim 1, characterized in that: The second LED light group output circuit is provided with a transistor Q14, one end of the transistor Q14 is connected to the second LED light group, the other end is connected to the diode signal rectifier bridge, and the other end is connected to one end of the parallel resistor R26.

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