LED constant current driving circuit with fault feedback

Abstract

The utility model provides an LED constant current drive circuit with fault feedback, comprising a power supply module for providing electric energy, the power supply module is respectively connected with an LED circuit and a comparison circuit, the output end of the comparison circuit is connected with the LED circuit, and the comparison circuit is used for adjusting the circulating current on an LEF circuit; the power supply module comprises a KL30-prot port for providing electric energy, the LED circuit comprises an LED lamp and a triode T1, an input end of the LED lamp is connected with the KL30-prot port, an output end of the LED lamp is connected with a collector electrode of the triode T1, a base electrode of the triode T1 is connected with the comparison circuit, and the comparison circuit adjusts the conduction degree of the comparison circuit by adjusting the voltage of the base electrode of the triode T1. According to the utility model, the current stability of the vehicle lamp can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to car lamp power supply technical field, concretely relates to a LED constant current drive circuit with fault feedback. BACKGROUND

[0002] When designing car lamp circuit, through the vehicle-mounted power supply, the lamp module integrates multiple functions such as daytime running lamp, turn signal, position lamp, etc., based on the different required brightness of different car lamps, and the power supply current is not the same, and when the car lamp is turned on, turned off or interfered, transient current is easy to produce, which can affect the performance and service life of the car lamp. Therefore, a constant current drive circuit is needed. SUMMARY

[0003] Therefore, the utility model wants to solve the problem to provide a LED constant current drive circuit with fault feedback, which can improve the stability of the car lamp current.

[0004] To solve the above technical problems, the utility model adopts the technical scheme of:

[0005] A LED constant current drive circuit with fault feedback, comprising a power supply module for providing electric energy, the power supply module is connected with LED circuit and comparison circuit respectively, the output end of the comparison circuit is connected with the LED circuit, and the current flowing through the LED circuit is adjusted.

[0006] The power supply module comprises a KL30-prot port for providing electric energy, the LED circuit comprises an LED lamp and a triode T1, the input end of the LED lamp is connected with the KL30-prot port, the output end of the LED lamp is connected with the collector of the triode T1, the base of the triode T1 is connected with the comparison circuit, and the comparison circuit adjusts the on-conductance of the triode T1 by adjusting the base voltage of the triode T1.

[0007] Further, the comparison circuit comprises a triode T5, a triode T6 and an operational amplifier chip U1, the emitter and the base of the triode T5 are connected with the KL30-prot port, the collector of the triode T5 is connected with the base of the triode T6 in sequence through a resistor R9, a resistor R11 and a resistor R17; the collector of the triode T5 is connected with the base of the triode T6, and the collector of the triode T6 is connected with the KL30-prot port.

[0008] The IN1+ pin of the operational amplifier chip U1 is connected between the resistor R11 and the resistor R17, the IN1+ pin and the IN1- pin of the operational amplifier chip U1 are connected in series with a capacitor C5, and the OUT1 pin of the operational amplifier chip U1 is connected with the base of the triode T1.

[0009] Further, the collector of the triode T5 is connected with the ground pole in series with the stabilizing diode D4.

[0010] Further, the KL30-prot port is connected with the ground pole in series with the capacitor C3 and the capacitor C4 respectively.

[0011] Further, the comparison circuit is provided with the fault feedback circuit between the comparison circuit and the vehicle lamp control module, the fault feedback circuit comprises the resistor R1 connected in series between the KL30-prot port and the IN2-pin of the operational amplifier chip U1, the IN2+ pin of the operational amplifier chip U1 is connected with the collector of the triode T1, and the OUT2-pin of the operational amplifier chip U1 is connected with the vehicle lamp control module in series with the reverse diode D1.

[0012] The LED constant current driving circuit with fault feedback has the advantages and positive effects that:

[0013] The LED circuit is provided with the triode T1 connected in series, the base of the triode T1 is connected with the comparison circuit, the conduction degree of the triode T1 is adjusted through the comparison circuit, the current on the LED circuit is controlled, and the stability of the current on the LED circuit is improved.

[0014] The triode T5, the triode T6 and the operational amplifier chip U1 are arranged in the comparison circuit, only the triode T5 is turned on when the output current of the power module does not exceed the preset value, the triode T5 and the triode T6 are turned on at the same time when the output current of the power module exceeds the preset value, the current on the triode T5 is shunted, the output voltage of the OUT1 pin of the operational amplifier chip U1 is reduced, the conduction degree of the triode T1 is reduced, and the stability of the current on the LED circuit is improved. BRIEF DESCRIPTION OF DRAWINGS

[0015] The drawings are used to provide further understanding of the LED constant current driving circuit with fault feedback, constitute a part of the specification, are used together with the embodiments of the LED constant current driving circuit with fault feedback to explain the LED constant current driving circuit with fault feedback, and do not constitute the limitation on the LED constant current driving circuit with fault feedback. In the drawings:

[0016] Figure 1 It is the overall system diagram of the LED constant current driving circuit with fault feedback of the LED constant current driving circuit with fault feedback;

[0017] Figure 2 It is the comparison circuit diagram of the LED constant current driving circuit with fault feedback of the LED constant current driving circuit with fault feedback;

[0018] Figure 3 It is the LED circuit diagram of the LED constant current driving circuit with fault feedback of the LED constant current driving circuit with fault feedback;

[0019] Figure 4 It is the fault feedback circuit diagram of the LED constant current driving circuit with fault feedback of the LED constant current driving circuit with fault feedback. Detailed Implementation

[0020] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0022] This utility model provides an LED constant current drive circuit with fault feedback, such as... Figure 1 As shown, it includes a power supply module that provides electrical energy. The power supply module is connected to an LED circuit and a comparator circuit. The comparator circuit receives the output current of the power supply module and compares it with a preset current. Based on the comparison result, it adjusts the power supply current on the LED circuit to achieve constant current power supply.

[0023] like Figure 3 As shown, the power supply module includes a KL30-prot port that provides power supply current. The LED circuit includes an LED and a transistor T1. The input terminal of the LED is connected to the KL30-prot port, and the output terminal of the LED is connected to the collector of the transistor T1. A resistor R12 is connected in series between the emitter and ground of the transistor T1. The base of the transistor T1 is connected to a comparator circuit. The comparator circuit adjusts the conduction of the transistor T1, thereby adjusting the conduction current on the transistor T1 and improving the stability of the current flowing through the LED.

[0024] like Figure 2 As shown, the comparator circuit includes diode D3, transistor T5, and transistor T6. A resistor R3 is connected in series between the emitter of transistor T5 and the KL30-prot port. A capacitor C6 is connected in series between the collector of transistor T5 and ground. Resistors R9, R11, and R17 are connected in series between the collector of transistor T5 and ground in sequence. A reverse-biased diode D3 is connected in series between the base of transistor T5 and the KL30-prot port. A resistor R16 is connected in series between the base of transistor T5 and ground. A resistor R10 is connected in series between the collector of transistor T5 and the base of transistor T6. A resistor R4 is connected in series between the collector of transistor T6 and the KL30-prot port. A capacitor C9 is connected in series between the emitter of transistor T6 and ground.

[0025] When the KL30-prot port is normally powered, the transistor T5 is turned on, the transistor T6 is not turned on, and the current output at the collector of the transistor T5 passes through the resistor R9, the resistor R11 and the resistor R17 in turn. When the output current of the KL30-prot port increases and exceeds the threshold value, the voltage at the collector of the transistor T5 increases, so that the transistor T6 is turned on. Due to the shunt of the transistor T6, the current passing through the transistor T5 decreases.

[0026] The zener diode D4 is connected in series between the collector of the transistor T5 and the ground. When the output current of the KL30-prot port is too large to cause the zener diode D4 to be reversely broken down, the voltage across the zener diode D4 remains stable, so that the voltage at the collector of the transistor T5 is prevented from being too high, and the control of the rear circuit is prevented from being interfered.

[0027] The IN1+ pin of the operational amplifier chip U1 is directly connected in series with the resistor R17, the capacitor C7 and the capacitor C8, respectively. The capacitor C5 is connected in series between the IN1+ pin and the IN1- pin of the operational amplifier chip U1. The OUT1 pin of the operational amplifier chip U1 is connected to the base of the transistor T1.

[0028] When the transistor T6 is turned on, the voltages at the IN1+ pin and the IN1- pin of the operational amplifier chip U1 decrease, so that the output voltage at the OUT1 pin of the operational amplifier chip U1 decreases, and the conductivity of the transistor T1 also decreases. Therefore, the stability of the current passing through the LED lamp is improved, and the frequent passing of transient large current through the LED lamp is prevented, so that the service life of the LED lamp is affected.

[0029] The capacitor C3 and the capacitor C4 are connected in series between the KL30-prot port and the ground, respectively. The capacitor C3 and the capacitor C4 are used to improve the stability of the voltage of the KL30-prot port, improve the detection accuracy of the comparison circuit, and improve the stability of the power supply voltage of the LED lamp.

[0030] The fault feedback circuit is arranged between the comparison circuit and the vehicle lamp control module. The fault feedback circuit is used to monitor the power supply current of the LED circuit, and feedback the power supply fault signal to the vehicle lamp control module in time.

[0031] As shown in Figure 4 The fault feedback circuit includes the diode D1 and the diode D2. The resistor R1 and the forward diode D2 are connected in series between the KL30-prot port and the ground. The IN2- pin of the operational amplifier chip U1 is connected between the resistor R1 and the diode D2. The resistor R2 is connected in series between the collector of the transistor T1 and the IN2+ pin of the operational amplifier chip U1. The OUT2- pin of the operational amplifier chip U1 is connected in series with the reverse diode D1 between the OUT2- pin of the operational amplifier chip U1 and the vehicle lamp control module.

[0032] When the LTD lamp is normal, the output voltage of the OUT2- pin of the operational amplifier chip U1 is not passed through because the diode D1 is reversed; when the LTD lamp is faulty, the voltage of the IN2- pin is unchanged, but the voltage of the IN2+ pin is reduced or 0V, the voltage of the OUT2- pin is reduced, the diode D1 is turned on, and the fault signal is transmitted to the vehicle lamp control module.

[0033] The above has carried out the detailed explanation to the embodiment of the utility model, but the content described can only be the preferred embodiment of the utility model, cannot be considered for limiting the implementation scope of the utility model. All equivalent changes and improvements made in the scope of the utility model should still belong to the scope covered by the patent.

Claims

1. An LED constant current driving circuit with fault feedback, characterized in that, The power module includes a KL30-prot port for providing electric energy, and the LED circuit includes an LED lamp and a triode T1, wherein the input end of the LED lamp is connected with the KL30-prot port, the output end of the LED lamp is connected with the collector of the triode T1, the base of the triode T1 is connected with the comparison circuit, and the comparison circuit adjusts the on-conductance of the triode T1 by adjusting the voltage of the base of the triode T1. The comparison circuit includes a triode T5, a triode T6 and an operational amplifier chip U1, wherein the emitter and the base of the triode T5 are connected with the KL30-prot port, the collector of the triode T5 is connected with the base of the triode T6 in sequence through a resistor R9, a resistor R11 and a resistor R17, and the collector of the triode T6 is connected with the KL30-prot port.

2. The LED constant current driving circuit with fault feedback according to claim 1, characterized in that, The IN1+ pin of the operational amplifier chip U1 is connected between the resistor R11 and the resistor R17, the IN1+ pin and the IN1- pin of the operational amplifier chip U1 are connected in series through a capacitor C5, and the OUT1 pin of the operational amplifier chip U1 is connected with the base of the triode T1. The collector and the ground of the triode T5 are connected in series through a stabilizing diode D4.

3. The LED constant current driving circuit with fault feedback according to claim 2, characterized in that, The KL30-prot port and the ground are connected in series through a capacitor C3 and a capacitor C4 respectively.

4. The LED constant current driving circuit with fault feedback according to claim 1, characterized in that, The comparison circuit and the vehicle lamp control module are provided with a fault feedback circuit, the fault feedback circuit includes a resistor R1 connected in series between the KL30-prot port and the IN2- pin of the operational amplifier chip U1, the IN2+ pin of the operational amplifier chip U1 is connected with the collector of the triode T1, and the OUT2- pin of the operational amplifier chip U1 is connected in series with the vehicle lamp control module through a reverse diode D1.

5. The LED constant current driving circuit with fault feedback according to claim 1, characterized in that, ​

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