A digital control method for LED driving power supply without electrolytic capacitor

Abstract

The invention relates to a digital control method of a non-electrolytic capacitor LED driving power supply. The digital controller achieves high power factor and constant current output by collecting the output voltage of the PFC circuit and the LED load current and performing weighted feedback, and determines the timing of the drive signal required by the switching tube of the half-bridge resonant circuit by collecting the output voltage of the rectifier circuit and the LED load power And the size of the duty cycle, when the instantaneous value of the PFC output voltage increases, the duty cycle of the switch tube increases, when the instantaneous value of the output voltage of the PFC circuit decreases, the duty cycle of the switch tube decreases, so that the half-bridge resonant circuit The working duty cycle of the switching tube can automatically follow the instantaneous value change of the PFC output voltage, thereby effectively suppressing the low-frequency ripple of the PFC circuit output voltage and reducing the capacity of the energy storage capacitor at the output end of the PFC circuit. Film capacitors can be used instead of electrolytic capacitors. Capacitor, to achieve electrolytic capacitance.

Description

technical field [0001] The invention relates to a digital control method of a non-electrolytic capacitor LED driving power supply. Background technique [0002] In recent years, LED technology has developed rapidly. It is popular among the public because of its advantages of energy saving, long life and high light efficiency, and it has become a new generation of lighting source. Since the LED drive power supply requires an electrolytic capacitor to balance the input and output power, and the life of the electrolytic capacitor decreases sharply with the increase of temperature, the advantages of the long life of the LED lamp cannot be fully utilized. Therefore, it is necessary to develop an LED driving power supply with high reliability, high power factor and long life that matches the LED light source. [0003] For high-power applications, the performance requirements of LED drive power usually adopt a two-stage structure. The first-stage power factor correction circuit us...

AI Technical Summary

Problems solved by technology

The lifespan of electrolytic capacitors is usually only about 10,000 hours, which is extremely inconsistent with the lifespan of LEDs of 80,000 to 100,000 hours, and the lifespan 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. Therefore, the electrolytic capacitor has become the main factor affecting the life of the LED drive power supply, and the electrolytic capacitor has a large volume, which limits the further improvement of the power density of the drive power supply.

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