LED driving circuit

Abstract

The invention provides an LED driving circuit. The LED driving circuit comprises a rectifying circuit, a power supplying circuit, a load driving circuit and a switch circuit. A zero-cross detecting unit of the switch circuit is used for detecting the source electrode voltage of a first power switch pipe to obtain the on-off time and the conduction time of a fly-wheel diode, and then LED constant current driving is achieved. According to the LED driving circuit, a driving power source can be simplified, the size of a PCB of the LED driving power source can be reduced, and the cost of an LED driving power application system is reduced; according to the driving circuit, the zero current time of the fly-wheel diode can be obtained with the only requirement for collecting the source electrode voltage of the first power switch pipe, and the design difficulty, the area and the cost of a chip can be reduced; when the driving circuit is in a BCM, the switch loss can be reduced, the power transfer efficiency is improved, and the EMI can be improved.

Description

technical field [0001] The invention relates to the field of circuit electronics and integrated circuits, in particular to a driving circuit for supplying power to LEDs. Background technique [0002] LED (Light Emitting Diode) is a semiconductor electronic component that can emit light. LED can only be turned on (energized) in one direction. When current flows, electrons and holes recombine in it to emit monochromatic light. Luminescence effect, and the wavelength and color of light are related to the type of semiconductor material used and the elemental impurities doped. It has the advantages of high efficiency, long life, not easy to break, high switching speed, high reliability, etc. that traditional light sources cannot match. Because LED has the advantages of energy saving and environmental protection, it is gradually popularized and used. At the same time, users have put forward higher and higher requirements for its performance, especially the cost control requiremen...

AI Technical Summary

Problems solved by technology

[0004] The flyback switching circuit uses the auxiliary winding NA to detect the zero-crossing moment of the current of the diode D, and the feedback circuit needs to use components such as rectifier diodes and voltage divider resistors, which will complicate the design of the entire circuit system and make The PCB board size of the LED drive circuit system increases, which will increase the cost of the LED power supply system and limit its use.

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