High-efficiency LED (light-emitting diode) drive circuit and drive method thereof

Abstract

According to a high-efficiency LED drive circuit and its drive method of the present invention, when the LED load fails, the secondary side of the flyback converter still absorbs the electric energy transmitted by the primary side, causing the problem of excessive charging on the capacitor, and Allowing the output voltage of the first-stage conversion circuit to fluctuate to a certain extent further reduces the volume and cost of the output capacitor so that no electrolytic capacitor is used, which further improves the reliability of the entire circuit. At the same time, the topology of the second-stage conversion circuit is preferably a non-isolated converter, and it is located on the low-voltage side of the transformer, so the withstand voltage requirements for the corresponding components are reduced, and high withstand voltage components are not required, thereby reducing costs. According to the LED drive circuit of the present invention, the signal representing the dimming of the system and the dimming signal representing the conduction angle of the thyristor can be calculated, and the current of the LED load can be controlled according to the result of the calculation without the need to convert the signal of the output side The system dimming signal is transmitted through the optocoupler, which further reduces the cost.

Description

technical field [0001] The invention relates to the field of LED lighting, in particular to a high-efficiency LED driving circuit and a driving method thereof. Background technique [0002] With the continuous innovation and rapid development of the lighting industry, coupled with the increasing importance of energy saving and environmental protection, LED lighting, as a revolutionary energy-saving lighting technology, is developing rapidly. However, due to the volt-ampere characteristics and temperature characteristics of the LED itself, the sensitivity of the LED to the current is higher than the sensitivity to the voltage, so the traditional power supply cannot directly supply power to the LED. Therefore, to use LED as a lighting source, we must first solve the problem of power drive. [0003] The principle block diagram of the traditional driving circuit that uses two-stage structure to supply power to LED is as follows: figure 1 As shown, the AC input power supply AC ...

AI Technical Summary

Problems solved by technology

[0004] In view of this, the purpose of the present invention is to provide a high-efficiency LED driving circuit and its driving method, to overcome the problems of high cost and low efficiency in the prior art