Automobile interior and exterior small lamp driving circuit

Abstract

The utility model belongs to the technical field of automobile LED control circuits, and particularly relates to an automobile interior and exterior small lamp driving circuit which comprises a power input, an LDO driving module and a constant-current driving circuit module, the constant-current driving circuit module has two modes, and after an LDO chip provides stable voltage required by LED voltage drop, the constant-current driving circuit module is connected with the power input. The constant current driving circuit provides constant current to drive multiple paths of LEDs, stable working voltage and working current can be provided for LED working, the circuit structure is simple, the number of used components is small, the cost is low, the circuit working efficiency is high, the components can be placed on a circuit board with a small size, the weight is light, and usable space inside and outside an automobile is saved. Due to the fact that the circuit is a multi-path parallel drive circuit and each string of circuit is only connected with one LED lamp bead, whether each branch circuit is short-circuited or open-circuited can be distinguished through input current, and maintenance and repair are easy.

Description

Technical Field

[0001] The utility model relates to the technical field of automobile LED control circuits, in particular to a driving circuit for an automobile interior and exterior small lamp. Background Art

[0002] The brightness of LED lights is determined by the current flowing through them. As a constant current load, LEDs have strict requirements on the working voltage and current. When the input voltage changes, the current flowing through the LED lights will change, and the brightness of the LEDs will also change. When the current flowing through the LED lights increases, the brightness of the LED lights becomes stronger, and vice versa.

[0003] In actual automotive electronic products, many require the brightness of LED lights to remain constant. Therefore, it is necessary to design a driving circuit that can keep the current flowing through the LED light constant under different input driving voltages, so that the brightness of the LED light remains constant. And with the development of the new energy vehicle industry, some constant current circuits that can only drive one string of LED light sources at the same time no longer meet the demand. If you want to realize an integrated circuit module that drives multiple strings of LEDs and multiple LED light sources at the same time, the circuit cost is relatively high. Utility Model Content

[0004] The purpose of the utility model is to provide a driving circuit for a small interior and exterior lamp of an automobile to solve the problems raised in the above-mentioned background technology.

[0005] To achieve the above-mentioned purpose, the utility model provides the following technical solutions: a small interior and exterior lamp driving circuit for an automobile, comprising a power input, an LDO driving module and a constant current driving circuit module, wherein the constant current driving circuit module has two modes, namely, using a PNP transistor or an NPN transistor driving circuit, and including an LED lamp bead inside the constant current driving circuit module; the power input and the output end of the LDO driving module are connected to the constant current driving circuit module, and each driving output end of the constant current driving circuit module is connected to an LED lamp bead;

[0006] The power input and LDO driving module includes a connector J1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, a TVS tube D2, a resistor R1, a resistor R2, a magnetic bead LF1, and a chip U1;

[0007] The constant current drive circuit module-PNP transistor interlocking constant current circuit comprises resistors R3, R4, R5, R6, PNP transistors Q1, Q2, Q3, Q4, and the LED lamp beads comprise LED1, LED2, and LED3;

[0008] The constant current drive circuit module - NPN transistor interlocking constant current circuit includes resistors R7, R8, R9, and R10, NPN transistors Q5, Q6, NPN transistors Q7, and Q8, and the LED lamp beads include LED4, LED5, and LED6.

[0009] Preferably, one end of the TVS tube D2 is connected to a 12V power input, the other end of the TVS tube D2 is grounded, the positive electrode of the diode D1 is connected to a 12V power input, the negative electrode of the diode D1 is connected to a capacitor C1 and a magnetic bead LF1, the other end of the capacitor C1 is grounded, the other end of the magnetic bead LF1 is connected to one end of the capacitor C2, one end of C5 and the 8th and 5th pins of the chip U1, the other ends of the capacitors C2 and C5 are grounded, one end of the resistor R1 is connected to the 1st pin, C4 and C3 of the chip U1, the other end of the resistor R1 is connected to the 3rd pin of the chip U1, one end of R2 and the other end of C4, the other end of the capacitor C3 is grounded, the other end of the resistor R2 is grounded, the 2nd and 7th pins of the chip U1 are suspended and not connected to any components, the 4th and 6th pins of the chip U1 are grounded, and the 1st pin of the chip U1 is a 5V power output.

[0010] Preferably, one end of the resistor R4, one end of the resistor R5, one end of the resistor R6, and the E pole of the PNP transistor Q1 are connected to the 5V output, the B pole of the PNP transistor Q1 is connected to the other end of the resistor R4 and the E pole of the PNP transistor Q2, the C pole of the PNP transistor Q1 is connected to the B pole of the PNP transistor Q2, the B pole of the PNP transistor Q3, the B pole of the PNP transistor Q4, and one end of the resistor R3, and the other end of the resistor R3 is grounded. The C pole of the PNP transistor Q2 is connected to the positive pole of the LED lamp bead LED1, the C pole of the PNP transistor Q3 is connected to the positive pole of the LED lamp bead LED2, the C pole of the PNP transistor Q4 is connected to the positive pole of the LED lamp bead LED3, the negative poles of the LED lamp beads LED1, LED2, and LED3 are grounded, the other end of the resistor R5 is connected to the E pole of the PNP transistor Q3, and the other end of the resistor R6 is connected to the E pole of the PNP transistor Q4.

[0011] Preferably, one end of the resistor R7, the positive electrode of the LED lamp bead LED4, the positive electrode of the LED lamp bead LED5, and the positive electrode of the LED lamp bead LED6 are connected to the 5V output, the other end of the resistor R7 is connected to the C pole of the NPN transistor Q5, the B pole of the NPN transistor Q6, the B pole of the NPN transistor Q7, and the B pole of the NPN transistor Q8, the cathode of the LED lamp bead LED4 is connected to the C pole of the NPN transistor Q6, and the cathode of the LED lamp bead LED5 is connected to the NPN transistor Q8. The C pole of the N-type transistor Q7 and the negative pole of the LED lamp bead LED6 are connected to the C pole of the NPN-type transistor Q8, the E pole of the NPN-type transistor Q6 is connected to one end of the resistor R8 and the B pole of the NPN-type transistor Q5, the E pole of the NPN-type transistor Q7 is connected to one end of the resistor R9, the E pole of the NPN-type transistor Q8 is connected to one end of the resistor R10, and the E pole of the NPN-type transistor Q5, the other end of the resistor R8, the other end of the resistor R9, and the other end of the resistor R10 are grounded.

[0012] Preferably, the model of the chip U1 is TLV767-Q1.

[0013] Compared with the prior art, the beneficial effects of the utility model are:

[0014] In this application, after the LDO chip provides the stable voltage required for the LED voltage drop, a constant current driving circuit provides a constant current to drive multiple LEDs, which can provide stable working voltage and working current for the LED operation, and the circuit structure is simple, the number of components used is small, the cost is low, and the circuit working efficiency is high. The components can be placed on a smaller circuit board with light weight, saving usable space inside and outside the car; it is easy to know the problem after the abnormal lighting, because the circuit is a multi-channel parallel driving circuit, and each string of circuits is only connected to one LED lamp bead, the input current can be used to identify whether each branch is short-circuited or open-circuited, and maintenance and repair are simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the schematic diagram of power input and LDO drive module, constant current drive circuit module - PNP type transistor interlock constant current;

[0016] Figure 2 It is the schematic diagram of power input, LDO drive module, constant current drive circuit module - NPN transistor interlocking constant current. DETAILED DESCRIPTION

[0017] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0018] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0019] Example

[0020] See also Figure 1-2 , the utility model provides a technical solution:

[0021] A small car interior and exterior lamp driving circuit includes a power input, an LDO driving module and a constant current driving circuit module. The constant current driving circuit module has two modes, namely, using a PNP transistor or an NPN transistor driving circuit, and including an LED lamp bead inside the constant current driving circuit module; the power input and the output end of the LDO driving module are connected to the constant current driving circuit module, and each driving output end of the constant current driving circuit module is connected to an LED lamp bead;

[0022] The power input and LDO driving module includes a connector J1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, a TVS tube D2, a resistor R1, a resistor R2, a magnetic bead LF1, and a chip U1;

[0023] The constant current drive circuit module-PNP transistor interlocking constant current circuit comprises resistors R3, R4, R5, R6, PNP transistors Q1, Q2, Q3, Q4, and the LED lamp beads comprise LED1, LED2, and LED3;

[0024] The constant current drive circuit module - NPN transistor interlocking constant current circuit includes resistors R7, R8, R9, and R10, NPN transistors Q5, Q6, NPN transistors Q7, and Q8, and the LED lamp beads include LED4, LED5, and LED6.

[0025] The LED connection method in this embodiment is a single LED connection, 3-way parallel connection, specifically two LEDs can be connected in series or a single LED can be connected in multiple ways in parallel. In this embodiment, the number of LEDs is 3, divided into 3 ways in parallel, and in other cases, the appropriate number of lamp beads can be set according to needs.

[0026] The above LED driving module can change its driving mode according to information such as the number of LEDs and LED power, such as adding a similar module to the transistor Q2. The module specifically includes the following components: resistor R4 and transistor Q2.

[0027] The following is an explanation of the working state of the constant current drive circuit module - PNP type transistor interlock constant current drive mode:

[0028] The input voltage VDD is 5V, that is, high level, and the B poles of PNP transistors Q2, Q3, and Q4 are pulled down to GND by R3. At this time, PNP transistors Q2, Q3, and Q4 are in the on state, and the current passing through R4, R5, and R6 is small. The voltage drop between the E pole and the B pole of Q1 is small. At this time, Q1 is in the off state. When the voltage drop across R4 reaches Vbe, Q1 is turned on, and current passes through R3. The B pole currents of Q2, Q3, and Q4 decrease, and the C pole current decreases accordingly, achieving the effect of current limiting. Therefore, the conduction of Q1 will limit the B pole currents of Q2, Q3, and Q4, so that the output current of the circuit is stable at a certain current value. This cycle is repeated, and finally the currents of each branch in the circuit are stabilized at ILED1=Vbe / R4, ILED2=Vbe / R5, and ILED3=Vbe / R6 (ignoring the B pole currents of Q2, Q3, Q4 and Q1 transistors). No matter how the power supply voltage VCC changes, the current remains constant.

[0029] The following is an explanation of the working state of the constant current drive circuit module - NPN type transistor interlocking constant current drive mode:

[0030] The input voltage VDD is 5V, that is, high level. The B poles of NPN transistors Q6, Q7, and Q8 are pulled up to VDD by R7, and NPN transistors Q6, Q7, and Q8 are turned on. At the same time, the B pole of NPN transistor Q5 is pulled high, and Q5 will be turned on. When Q5 is turned on, the B pole voltage of Q6, Q7, and Q8 transistors is pulled down and cut off. The load LED does not work, and no current flows through Q5. The B pole voltage of Q5 is pulled down to the ground, Q5 is cut off, and the B poles of Q6, Q7, and Q8 are released, and Q6, Q7, and Q8 are turned on again. This cycle works repeatedly, and finally the current of each branch in the circuit is stabilized at ILED4=Vbe / R8, ILED5=Vbe / R9, and ILED6=Vbe / R10 (ignore the B pole current of Q6, Q7, Q8 and Q5 transistors). No matter how the power supply voltage VCC changes, the current remains constant.

[0031] This constant current source is expandable, and new branches are connected in parallel. The current of the new branches follows Ohm's law. The smaller the branch resistance, the greater the branch LED current.

[0032] One end of the TVS tube D2 is connected to the 12V power input, and the other end of the TVS tube D2 is grounded. The positive electrode of the diode D1 is connected to the 12V power input, and the negative electrode of the diode D1 is connected to the capacitor C1 and the magnetic bead LF1. The other end of the capacitor C1 is grounded. The other end of the magnetic bead LF1 is connected to one end of the capacitor C2, one end of C5 and the 8th and 5th pins of the chip U1. The other ends of the capacitors C2 and C5 are grounded. One end of the resistor R1 is connected to the 1st pin, C4 and C3 of the chip U1. The other end of the resistor R1 is connected to the 3rd pin of the chip U1, one end of R2 and the other end of C4. The other end of the capacitor C3 is grounded. The other end of the resistor R2 is grounded. The 2nd and 7th pins of the chip U1 are suspended without connecting any components. The 4th and 6th pins of the chip U1 are grounded. The 1st pin of the chip U1 is a 5V power output.

[0033] One end of the resistor R4, one end of the resistor R5, one end of the resistor R6, and the E pole of the PNP transistor Q1 are connected to the 5V output, the B pole of the PNP transistor Q1 is connected to the other end of the resistor R4 and the E pole of the PNP transistor Q2, the C pole of the PNP transistor Q1 is connected to the B pole of the PNP transistor Q2, the B pole of the PNP transistor Q3, the B pole of the PNP transistor Q4, and one end of the resistor R3, and the other end of the resistor R3 is grounded. The C pole of the PNP transistor Q2 is connected to the positive pole of the LED lamp bead LED1, the C pole of the PNP transistor Q3 is connected to the positive pole of the LED lamp bead LED2, the C pole of the PNP transistor Q4 is connected to the positive pole of the LED lamp bead LED3, the negative poles of the LED lamp beads LED1, LED2, and LED3 are grounded, the other end of the resistor R5 is connected to the E pole of the PNP transistor Q3, and the other end of the resistor R6 is connected to the E pole of the PNP transistor Q4.

[0034] One end of the resistor R7, the positive pole of the LED lamp bead LED4, the positive pole of the LED lamp bead LED5, and the positive pole of the LED lamp bead LED6 are connected to the 5V output, the other end of the resistor R7 is connected to the C pole of the NPN transistor Q5, the B pole of the NPN transistor Q6, the B pole of the NPN transistor Q7, and the B pole of the NPN transistor Q8, the cathode of the LED lamp bead LED4 is connected to the C pole of the NPN transistor Q6, and the cathode of the LED lamp bead LED5 is connected to the NPN transistor Q8. The C pole of the transistor Q7 and the negative pole of the LED lamp bead LED6 are connected to the C pole of the NPN transistor Q8, the E pole of the NPN transistor Q6 is connected to one end of the resistor R8 and the B pole of the NPN transistor Q5, the E pole of the NPN transistor Q7 is connected to one end of the resistor R9, the E pole of the NPN transistor Q8 is connected to one end of the resistor R10, and the E pole of the NPN transistor Q5, the other end of the resistor R8, the other end of the resistor R9, and the other end of the resistor R10 are grounded.

[0035] The model of the chip U1 is TLV767-Q1.

[0036] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. For those skilled in the art, it is obvious that the utility model is not limited to the details of the above exemplary embodiments, and the utility model can be implemented in other specific forms without departing from the spirit or basic features of the utility model; therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the utility model is limited by the attached claims rather than the above description. Therefore, it is intended to include all changes within the meaning and scope of the equivalent elements of the claims in the utility model, and any figure marks in the claims should not be regarded as limiting the claims involved.

[0037] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A small car interior and exterior lamp driving circuit, comprising a power input, an LDO driving module and a constant current driving circuit module, characterized in that: There are two ways to describe the constant current drive circuit module, namely, using a PNP transistor or an NPN transistor drive circuit, and including an LED lamp bead inside the constant current drive circuit module; the power input and the output end of the LDO drive module are connected to the constant current drive circuit module, and each drive output end in the constant current drive circuit module is connected to an LED lamp bead; The power input and LDO driving module includes a connector J1, a capacitor C1, a capacitor C2, a capacitor C3, a capacitor C4, a capacitor C5, a diode D1, a TVS tube D2, a resistor R1, a resistor R2, a magnetic bead LF1, and a chip U1; The constant current drive circuit module-PNP transistor interlocking constant current circuit comprises resistors R3, R4, R5, R6, PNP transistors Q1, Q2, Q3, Q4, and the LED lamp beads comprise LED1, LED2, and LED3; The constant current drive circuit module - NPN transistor interlocking constant current circuit includes resistors R7, R8, R9, and R10, NPN transistors Q5, Q6, NPN transistors Q7, and Q8, and the LED lamp beads include LED4, LED5, and LED6.

2. The driving circuit for an automobile interior and exterior small lamp according to claim 1, characterized in that: One end of the TVS tube D2 is connected to the 12V power input, and the other end of the TVS tube D2 is grounded. The positive electrode of the diode D1 is connected to the 12V power input, and the negative electrode of the diode D1 is connected to the capacitor C1 and the magnetic bead LF1. The other end of the capacitor C1 is grounded. The other end of the magnetic bead LF1 is connected to one end of the capacitor C2, one end of C5 and the 8th pin and the 5th pin of the chip U1. The other ends of the capacitors C2 and C5 are grounded. One end of the resistor R1 is connected to the 1st pin, C4 and C3 of the chip U1. The other end of the resistor R1 is connected to the 3rd pin of the chip U1, one end of R2 and the other end of C4. The other end of the capacitor C3 is grounded. The other end of the resistor R2 is grounded. The 2nd and 7th pins of the chip U1 are suspended without connecting any components. The 4th and 6th pins of the chip U1 are grounded. The 1st pin of the chip U1 is a 5V power output.

3. The driving circuit for an automobile interior and exterior small lamp according to claim 1, characterized in that: One end of the resistor R4, one end of the resistor R5, one end of the resistor R6, and the E pole of the PNP transistor Q1 are connected to the 5V output, the B pole of the PNP transistor Q1 is connected to the other end of the resistor R4 and the E pole of the PNP transistor Q2, the C pole of the PNP transistor Q1 is connected to the B pole of the PNP transistor Q2, the B pole of the PNP transistor Q3, the B pole of the PNP transistor Q4, and one end of the resistor R3, and the other end of the resistor R3 is grounded. The C pole of the PNP transistor Q2 is connected to the positive pole of the LED lamp bead LED1, the C pole of the PNP transistor Q3 is connected to the positive pole of the LED lamp bead LED2, the C pole of the PNP transistor Q4 is connected to the positive pole of the LED lamp bead LED3, the negative poles of the LED lamp beads LED1, LED2, and LED3 are grounded, the other end of the resistor R5 is connected to the E pole of the PNP transistor Q3, and the other end of the resistor R6 is connected to the E pole of the PNP transistor Q4.

4. The driving circuit for an automobile interior and exterior small lamp according to claim 1, characterized in that: One end of the resistor R7, the positive pole of the LED lamp bead LED4, the positive pole of the LED lamp bead LED5, and the positive pole of the LED lamp bead LED6 are connected to the 5V output, the other end of the resistor R7 is connected to the C pole of the NPN transistor Q5, the B pole of the NPN transistor Q6, the B pole of the NPN transistor Q7, and the B pole of the NPN transistor Q8, the cathode of the LED lamp bead LED4 is connected to the C pole of the NPN transistor Q6, and the cathode of the LED lamp bead LED5 is connected to the NPN transistor Q8. The C pole of the transistor Q7 and the negative pole of the LED lamp bead LED6 are connected to the C pole of the NPN transistor Q8, the E pole of the NPN transistor Q6 is connected to one end of the resistor R8 and the B pole of the NPN transistor Q5, the E pole of the NPN transistor Q7 is connected to one end of the resistor R9, the E pole of the NPN transistor Q8 is connected to one end of the resistor R10, and the E pole of the NPN transistor Q5, the other end of the resistor R8, the other end of the resistor R9, and the other end of the resistor R10 are grounded.

5. The driving circuit for an automobile interior and exterior small lamp according to claim 1, characterized in that: The model of the chip U1 is TLV767-Q1.

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