Design of PWM dimming LED driver

In order to solve the problems of the requirement of emerge-saving and dimming in many different situations,the dimmable LED driver was investigated.The relative merits and the applications of the three dimming methods were analyzed,including PWM dimming,analog dimming,and SCR dimming,a PWM dimmable LED driver,which consists of a single-stage PFC constant voltage circuit based on L6562 and a constant current circuit based on HV9910,was presented to implement dimming.The whole performance was evaluated on the PWM dimmable LED driver,the sample of 40 W PWM dimmable LED driver was tested.The experimental results show that the LED driver has many advantages,such as high power factor and efficiency,dimming range around 2%～100%,very small load regulation,and which can work stable.