Constant current control device for LED circuits

Abstract

This utility model belongs to the field of LED control circuit technology, and particularly relates to a constant current control device for LED circuits. The device includes: an LED circuit for connecting to the working voltage; a switching circuit connected to the LED circuit; a current detection circuit connected to the switching circuit; a signal amplification circuit connected to the current detection circuit; and a reference comparison circuit including an adjustable precision reference source, one end of which is connected to the signal amplification circuit, and the other end of which is connected to the switching circuit. This device, through the switching circuit, current detection circuit, signal amplification circuit, and reference comparison circuit, forms a closed-loop control circuit, automatically adjusting the current of the LED circuit, solving the problem of current being affected by temperature and power supply fluctuations, and significantly improving the stability and lifespan of the LED operation.

Description

Technical Field

[0001] This application relates to the field of LED control circuit technology, and in particular to a constant current control device for LED circuits. Background Technology

[0002] LEDs are widely used due to their high efficiency and energy saving, leading to a surge in demand for high-power LEDs and multi-channel LEDs. However, their operating current is easily affected by temperature and power supply. Constant voltage power supply can cause current fluctuations, creating a vicious cycle that leads to uneven brightness, shortened lifespan, or even burnout. In multi-channel scenarios, current imbalance can also occur due to differences in components. Most related technologies use linear current regulator circuits to adjust the output current, but these circuits are inefficient and generate significant heat. Another approach is to use switching-type LED constant current control, which regulates the output current through the high-frequency switching of a switching transistor. While this solution is efficient, it may be difficult to independently and accurately control multiple channels, or it may require multiple chips, resulting in high cost and reduced reliability. Furthermore, some solutions lack sufficient current detection accuracy and response speed.

[0003] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0004] In view of at least one of the above technical problems, this application provides a constant current control device for LED circuits.

[0005] This application provides a constant current control device for an LED circuit, the device comprising:

[0006] LED circuitry is used to connect to the operating voltage;

[0007] The switching circuit is connected to the LED circuit.

[0008] The current detection circuit is connected to the switching circuit.

[0009] The signal amplification circuit is connected to the current detection circuit.

[0010] The reference comparator circuit includes an adjustable precision reference source, one end of which is connected to a signal amplification circuit, and the other end of which is connected to a switching circuit.

[0011] This device, through a closed-loop control circuit consisting of a switching circuit, a current detection circuit, a signal amplification circuit, and a reference comparison circuit, automatically adjusts the current of the LED circuit, solving the problem of current being affected by temperature and power supply fluctuations, and significantly improving the working stability and lifespan of the LED.

[0012] In some possible implementations, the switching circuit includes a power switch transistor, the drain of which is connected to the LED circuit, the source of which is connected to the current detection circuit, and the gate of which is connected to an adjustable precision reference source.

[0013] In some possible implementations, the power switch is an N-channel enhancement-mode MOSFET.

[0014] In some possible implementations, the current sensing circuit includes a sixth resistor, one end of which is connected to the switching circuit, the other end of which is grounded, and the input of the signal amplification circuit is connected in parallel with the sixth resistor.

[0015] In some possible implementations, the signal amplification circuit includes an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor. The first input terminal of the operational amplifier is connected to one end of the current detection circuit through the fourth resistor, the second input terminal of the operational amplifier is connected to the other end of the current detection circuit through the fifth resistor, the output terminal of the operational amplifier is connected to an adjustable precision reference source, and a third resistor is connected between the output terminal of the operational amplifier and the first input terminal of the operational amplifier.

[0016] The present invention will be further described below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the constant current control device for an LED circuit.

[0019] Figure 2 This is a circuit diagram of a constant current control device for an LED circuit. Detailed Implementation

[0020] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0021] Please see Figure 1 and Figure 2 , Figure 1 This is a schematic diagram of the constant current control device for an LED circuit. Figure 2 This is a circuit diagram of a constant current control device for an LED circuit. One embodiment provides a constant current control device for an LED circuit 100, the device including: an LED circuit 100, a switching circuit 200, a current detection circuit 300, a signal amplification circuit 400, and a reference comparison circuit 500.

[0022] The LED circuit 100 includes multiple LEDs connected in series. The LED circuit 100 is connected to the operating voltage to power the LEDs. A switching circuit 200 is connected in series with the LED circuit 100 to control the current flow of the LED circuit 100. A current detection circuit 300 is connected in series with the switching circuit 200 to collect the operating current of the LED circuit 100. A signal amplification circuit 400 is connected to the current detection circuit 300, receiving and amplifying the signal from the current detection circuit 300. The reference comparison circuit 500 includes an adjustable precision reference source U1. One end of the adjustable precision reference source U1 is connected to the signal amplification circuit 400, and the other end is connected to the switching circuit 200. One end of the adjustable precision reference source U1 receives the output of the signal amplification circuit 400, and the other end provides feedback to control the on / off state of the switching circuit 200.

[0023] During operation, after the LED circuit 100 is connected to the operating voltage, current flows through the switching circuit 200. The current detection circuit 300 collects the current signal and transmits it to the signal amplification circuit 400. The amplified signal is input to the adjustable precision reference source U1, compared with the internal reference, and then outputs a control signal to adjust the on / off state of the switching circuit 200, ultimately stabilizing the LED current.

[0024] This device, through a switch circuit 200, a current detection circuit 300, a signal amplification circuit 400, and a reference comparison circuit 500, forms a closed-loop control circuit to automatically adjust the current of the LED circuit 100, solving the problem of current being affected by temperature and power supply fluctuations, and significantly improving the working stability and lifespan of the LED.

[0025] like Figure 1 and Figure 2 As shown, in some embodiments, the switching circuit 200 includes a power switch Q1, the drain of the power switch Q1 is connected to the LED circuit 100, the source of the power switch Q1 is connected to the current detection circuit 300, and the gate of the power switch Q1 is connected to the adjustable precision reference source U1.

[0026] When the amplified signal is input to the adjustable precision reference source U1, the LED operating current exceeds the set value, causing the adjustable precision reference source U1 to conduct. This pulls the drive voltage of the power switch Q1 down to a low level, thus turning off the power switch Q1. After the power switch Q1 is turned off, no current flows through the current detection circuit 300, the signal amplification circuit 400 outputs a low level, and the power switch Q1 is cut off, making the drive voltage high. This causes the power switch Q1 to conduct again, and this cycle continues to control the operating current of the LED circuit 100 at a constant value.

[0027] The power switching transistor Q1 has a fast switching speed and strong current carrying capacity, making it suitable for the current regulation requirements of high-power LEDs, and it also has better regulation accuracy and response speed.

[0028] like Figure 1 and Figure 2 As shown, in some embodiments, the power switch Q1 is an N-channel enhancement-mode MOSFET. Thus, the N-channel enhancement-mode MOSFET is suitable for high-voltage side control, exhibiting low switching losses, low on-resistance, reduced circuit heating, and improved efficiency. Simultaneously, it possesses good linearity in its switching characteristics, facilitating fine current adjustment and ensuring constant current accuracy.

[0029] like Figure 1 and Figure 2 As shown, in some embodiments, the current detection circuit 300 includes a sixth resistor R6, one end of which is connected to the switching circuit 200, and the other end of which is grounded. The input terminal of the signal amplification circuit 400 is connected in parallel with the sixth resistor R6. Thus, a single resistor serves as the detection element, resulting in a very simple and low-cost circuit. It directly converts current into voltage using Ohm's law, providing a reliable basic signal for constant current regulation.

[0030] like Figure 1 and Figure 2 As shown, in some embodiments, the signal amplification circuit 400 includes an operational amplifier U2A, a third resistor R3, a fourth resistor R4, and a fifth resistor R5. The first input terminal of the operational amplifier U2A is connected to one end of the current detection circuit 300 through the fourth resistor R4, and the second input terminal of the operational amplifier U2A is connected to the other end of the current detection circuit 300 through the fifth resistor R5. The output terminal of the operational amplifier U2A is connected to the adjustable precision reference source U1, and the third resistor R3 is connected between the output terminal and the first input terminal of the operational amplifier U2A. The differential amplification structure of the operational amplifier U2A can suppress common-mode interference and improve signal purity. In addition, by precisely setting the amplification factor through the resistor ratio, the weak voltage signal of the sixth resistor R6 is amplified to a range suitable for reference source processing, which greatly improves the subsequent comparison accuracy and ensures the accuracy of constant current control.

[0031] In the embodiments of this application, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0032] The above are merely preferred embodiments of this application and do not constitute any limitation on this application. Any person skilled in the art can make many possible variations and modifications to the technical solution of this application, or modify it into equivalent embodiments, without departing from the scope of the technical solution of this application. Therefore, all equivalent changes made based on the shape, structure, and principle of this application without departing from the content of the technical solution of this application should be covered within the protection scope of this application.

Claims

1. A constant current control device for an LED circuit, characterized in that, The device includes: LED circuitry is used to connect to the operating voltage; A switching circuit is connected to the LED circuit. A current detection circuit is connected to the switching circuit; A signal amplification circuit is connected to the current detection circuit. The reference comparison circuit includes an adjustable precision reference source, one end of which is connected to the signal amplification circuit, and the other end of which is connected to the switching circuit.

2. The constant current control device for LED circuits according to claim 1, characterized in that, The switching circuit includes a power switch transistor, the drain of which is connected to the LED circuit, the source of which is connected to the current detection circuit, and the gate of which is connected to the adjustable precision reference source.

3. The constant current control device for LED circuits according to claim 2, characterized in that, The power switch is an N-channel enhancement-mode MOSFET.

4. The constant current control device for LED circuits according to claim 1, characterized in that, The current detection circuit includes a sixth resistor, one end of which is connected to the switching circuit and the other end of which is grounded. The input terminal of the signal amplification circuit is connected in parallel with the sixth resistor.

5. The constant current control device for LED circuits according to claim 1, characterized in that, The signal amplification circuit includes an operational amplifier, a third resistor, a fourth resistor, and a fifth resistor. The first input terminal of the operational amplifier is connected to one end of the current detection circuit through the fourth resistor. The second input terminal of the operational amplifier is connected to the other end of the current detection circuit through the fifth resistor. The output terminal of the operational amplifier is connected to the adjustable precision reference source. The third resistor is connected between the output terminal of the operational amplifier and the first input terminal of the operational amplifier.

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