CN204272424U - Low-power BUCK circuit LED drive power supply that meets electromagnetic compatibility - Google Patents

Abstract

The utility model provides a kind of small-power BUCK circuit LED drive power meeting electromagnetic compatibility, comprise the current rectifying and wave filtering circuit connected successively, the typical BUCK circuit controlled by integrated chip U1 and electromagnetic compatibility anti-jamming circuit, current rectifying and wave filtering circuit input, namely, electrical network 220Vac voltage is directly connected between 2 pin of fuse F1 and 1 pin of safety electric capacity CX1, the output of current rectifying and wave filtering circuit, that is, 1 pin of inductance L 1 is connected with 1 pin of electrochemical capacitor C1 and 2 pin respectively with ground GND; Electric capacity C1 is the input of the typical BUCK circuit controlled by integrated chip U1, electromagnetic compatibility anti-jamming circuit anode is connected with power supply output cathode, negative terminal is connected with power supply output negative pole, and negative terminal series capacitance C4 to GND, 1 pin of electric capacity C3 in the typical BUCK circuit controlled by integrated chip U1 is connected with 2 pin of the electric capacity C4 of electromagnetic compatibility anti-jamming circuit.In the LED drive power based on small-power BUCK circuit, increase electromagnetic compatibility anti-jamming circuit part, electromagnetic compatibility circuit structure is simple, and Component selection is flexible, the electromagnetic compatibility problem of simple and effective solution small-power BUCK circuit LED drive power.

Description

Low-power BUCK circuit LED drive power supply that meets electromagnetic compatibility

technical field

The utility model relates to the field of LED driving power supply, in particular to a low-power BUCK circuit LED driving power supply meeting the requirement of electromagnetic compatibility.

Background technique

With the continuous development of society and science and technology, LED lighting will gradually replace traditional lighting. LED driving power based on BUCK circuit is widely used in low-power LED driving power due to its simple structure and low cost. At the same time, with the development of LED lighting, its safety requirements are gradually following up, so electromagnetic compatibility has become the key to the design of LED driving power.

Contents of the invention

The utility model researches and improves the electromagnetic compatibility problem of the LED driving power supply of the low-power BUCK circuit, and provides an electromagnetic compatibility anti-interference circuit to meet the electromagnetic compatibility problem of the LED driving power supply of the low-power BUCK circuit.

The technical scheme of the utility model is as follows:

A low-power BUCK circuit LED drive power supply that satisfies electromagnetic compatibility, including a rectification and filtering circuit connected in sequence, a typical BUCK circuit controlled by an integrated chip U1, and an electromagnetic compatibility anti-interference circuit. Pin 1 and pin 1 of safety capacitor CX1 are directly connected to the power grid 220Vac voltage, the output end of the rectification filter circuit, that is, pin 1 of inductor L1 and ground GND are respectively connected to pin 1 and pin 2 of electrolytic capacitor C1; capacitor C1 is The input terminal of a typical BUCK circuit controlled by the integrated chip U1, the positive terminal of the EMC anti-interference circuit is connected to the positive pole of the power output, the negative terminal is connected to the negative pole of the power output, and the negative terminal is connected in series with the capacitor C4 to GND, a typical buck circuit controlled by the integrated chip U1 Pin 1 of capacitor C3 in the BUCK circuit is connected to pin 2 of capacitor C4 in the EMC anti-interference circuit.

Furthermore, the positive terminal of the EMC anti-jamming circuit is connected in series with the capacitor C5 to GND, and the pin 2 of the capacitor C3 in the typical BUCK circuit controlled by the integrated chip U1 is connected to the pin 2 of the capacitor C5 of the EMC anti-jamming circuit.

Further, the capacitances of capacitors C4 and C5 range from 10nF to 56nF.

Further, the rated working voltage of the capacitors C4 and C5 is ≥500V.

The beneficial technical effects of the utility model are: the electromagnetic compatibility anti-interference circuit part is added to the LED drive power supply based on the low-power BUCK circuit, the electromagnetic compatibility circuit structure is simple, the component selection is flexible, and it can be solved simply and effectively with appropriate PCB drawing Electromagnetic Compatibility of Low Power BUCK Circuit LED Driver Power Supply.

Description of drawings

Fig. 1 is a kind of preferred circuit schematic diagram of the present utility model;

Fig. 2 is another preferred circuit principle diagram of the utility model.

Detailed ways

The specific embodiment of the utility model will be further described below in conjunction with the accompanying drawings.

As shown in FIG. 1 , the circuit of this LED driving power supply includes a rectification and filtering circuit 1 connected in sequence, a typical BUCK circuit 2 controlled by an integrated chip U1 , and an electromagnetic compatibility anti-interference circuit 3 . The input end of the rectification filter circuit, that is, the 2nd pin of the fuse F1 and the 1st pin of the safety capacitor CX1 are directly connected to the power grid 220Vac voltage; the output end of the rectification filter circuit, that is, the 1st pin of the inductor L1 and the ground GND are respectively connected to the electrolytic capacitor Pin 1 and pin 2 of C1 are connected, C1 is the input end of typical BUCK circuit 2 controlled by integrated chip U1; pin 1 of capacitor C3 in typical BUCK circuit 2 controlled by integrated chip U1 is in phase with pin 2 of C4, electromagnetic The compatible circuit includes the positive terminal ("+") connected to the positive output of the power supply, the negative terminal ("-") connected to the negative output of the power supply, and the negative terminal ("-") connected in series with the capacitor C4 to GND. The electromagnetic compatibility anti-interference circuit 3 has a simple structure, and according to the test results, only the capacitor C4 can be used to meet the requirements of electronic compatibility. The capacitance value of capacitor C4 is recommended to be used in the range of 10~56nF. In order to ensure the reliability of the LED drive power supply, its rated working voltage is recommended to be ≥500V.

In order to further optimize electromagnetic compatibility, two capacitors, C4 and C5, can be used at the same time. As shown in Figure 2, pin 1 of capacitor C3 in a typical BUCK circuit 2 controlled by integrated chip U1 is in phase with pin 1 of C4, and capacitor C3 Pin 2 of C5 is connected to pin 2 of C5; the electromagnetic compatibility circuit includes the positive terminal ("+") connected to the positive pole of the power supply output, the negative terminal ("-") connected to the negative pole of the power supply output, and the positive terminal ("+") connected in series with the capacitor C5 to GND, negative terminal ("-") in series with capacitor C4 to GND. Properly adjusting the capacitance ranges of the two can well meet the electromagnetic compatibility requirements. Capacitors C4 and C5 are recommended to use a range of 10~56nF. In order to ensure the reliability of the LED drive power supply, it is recommended that their rated working voltage be ≥500V. When drawing the PCB, in a typical BUCK circuit 2 controlled by the integrated chip U1, the copper foil path between pin 1 of the diode D1, pins 5 and 6 of the integrated chip U1, and pin 2 of the inductor L2 should be as short as possible; pin 2 of the diode D1 The copper foil path between capacitor C3 and capacitor C3 should be as short as possible; the copper foil path between capacitor C4 in EMC circuit 3 and the negative pole of the power output should be as short as possible; the copper foil path between capacitor C5 and the power output should be as short as possible.

The working principle of the utility model is as follows:

The 220Vac input passes through the rectification and filtering circuit 1, and the typical BUCK circuit 2 controlled by the integrated chip U1 drives the light-emitting diode LED with a constant current. Since the BUCK circuit works in a high-frequency state, the voltage and current change rate is large, resulting in electromagnetic compatibility problems. After the typical BUCK circuit 2 controlled by chip U1, an EMC anti-interference circuit 3 is added, which can effectively absorb the switching noise generated by U1's built-in MOS and diode D1, reduce the voltage and current change rate of both, and solve the EMC problem simply and effectively. question.

The main components list in Figure 1:

serial number Component code Component type Component parameters or models 1 F1 Fuse resistance RXF-10Ω-0.5W 2 CX1,C3 Metal Film Capacitors CL21X-400V-0.1uF 3 BD1 rectifier bridge MB8S 4 L1 Color Code Inductance AL0510-1mH 5 L2 inductance EE10-14mH 6 C1 electrolytic capacitor LKF-4.7uF-400V 7 R1, R3, R4, R6 Chip Resistor 1206/0805 8 C2,C4,C5 Chip capacitors 1206/0805 9 U1 Integrated chip DU8613 10 C1 electrolytic capacitor GT-25V-220uF (6.3*11 )_SAMXON 11 D1 SMD diode ES1J

The above are only preferred implementations of the utility model, and the utility model is not limited to the above examples. It can be understood that other improvements and changes directly derived or conceived by those skilled in the art without departing from the spirit and concept of the present utility model shall be considered to be included in the protection scope of the present utility model.

Claims (4)

1. A low-power BUCK circuit LED drive power supply that satisfies electromagnetic compatibility, is characterized in that: comprise the rectifying and filtering circuit connected in sequence, the typical BUCK circuit and electromagnetic compatibility anti-jamming circuit controlled by integrated chip U1, rectifying and filtering circuit input end, That is, the 2nd pin of the fuse F1 and the 1st pin of the safety capacitor CX1 are directly connected to the 220Vac voltage of the power grid, and the output end of the rectification filter circuit, that is, the 1st pin of the inductor L1 and the ground GND are respectively connected to the 1st pin and 2nd pin of the electrolytic capacitor C1. The capacitor C1 is the input terminal of a typical BUCK circuit controlled by the integrated chip U1. The positive terminal of the EMC anti-interference circuit is connected to the positive terminal of the power supply output, the negative terminal is connected to the negative terminal of the power supply output, and the negative terminal is connected in series with the capacitor C4 to GND. Pin 1 of the capacitor C3 in the typical BUCK circuit controlled by the integrated chip U1 is connected to pin 2 of the capacitor C4 of the EMC anti-interference circuit. 2. The low-power BUCK circuit LED drive power supply satisfying electromagnetic compatibility according to claim 1, characterized in that: the positive terminal of the electromagnetic compatibility anti-interference circuit is connected in series with the capacitor C5 to GND, and the capacitor in the typical BUCK circuit controlled by the integrated chip U1 Pin 2 of C3 is connected with pin 2 of capacitor C5 of the EMC anti-jamming circuit. 3. The low-power BUCK circuit LED drive power supply satisfying electromagnetic compatibility according to claim 2, characterized in that: the capacitors C4 and C5 have a capacitance ranging from 10 to 56nF. 4. The low-power BUCK circuit LED drive power supply satisfying electromagnetic compatibility according to claim 2 or 3, characterized in that: the rated working voltage of capacitors C4 and C5 is ≥ 500V.