A single-stage non-isolated high power factor electrolytic capacitor-less LED drive power supply

Abstract

The invention relates to a single-stage non-isolated high power factor electrolytic capacitor LED drive power supply, comprising an AC input power supply, an input rectification circuit, a flyback conversion circuit, an auxiliary circuit, an LED load and the like. The flyback conversion circuit works in the current discontinuous mode to realize the power factor correction function and provide constant current output for the LED load; the auxiliary circuit is composed of an auxiliary switch tube, an auxiliary diode and an energy storage capacitor, and is used to balance the instantaneous power between input and output. power and absorb the voltage spike of the switching tube. The invention can greatly reduce the low-frequency ripple of the LED load current, so that a small-capacity film capacitor can be used instead of a large-capacity electrolytic capacitor. The invention has the advantages of low voltage stress of the switching tube, high power factor, and high reliability.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a single-stage non-isolated high power factor electrolytic capacitor-less LED drive power supply. Background technique [0002] With its many advantages such as energy saving, environmental protection, high efficiency and long life, LED has become a new generation of green lighting source. With the maturity of LED lighting technology, it is widely used in various fields. [0003] In the case of AC power supply, in order to meet the harmonic requirements of IEC61000-3-2, LED drive power supply needs to perform power factor correction. Single-stage power factor correction circuit topology is widely used in low-power applications due to its advantages of simple structure, low cost, high power factor and high efficiency. However, due to the imbalance between the instantaneous input power and the constant output power of the single-stage power factor LED drive circuit, the...

AI Technical Summary

Problems solved by technology

However, due to the imbalance between the instantaneous input power and the constant output power of the single-stage power factor LED drive circuit, there is a large low-frequency ripple in the output current, and it is usually necessary to use a large-capacity electrolytic capacitor as an energy storage capacitor to balance it. The service life of electrolytic capacitors is often only a few thousand hours, far lower than the service life of LED light-emitting diodes, and the service life of electrolytic capacitors is greatly affected by the ambient temperature. Every time the temperature rises by 10 degrees, its service life will be reduced by half, so the use of electrolytic capacitors It has become the main factor affecting the life of LED drive power supply, restricting the development of high-performance LED drive power supply

Images