Design Considerations for LED Thermal Stress Minimization in Electrolytic Capacitor-Less Single Stage Power Converter

The Light-emitting diode (LED) driving current of an electrolytic capacitor-less ac-to-dc single stage power converter with power factor correction contains pulsating component whose frequency is twice the line frequency. The luminous efficacy of a LED is proportional to the average value of the pulsating current. However, the peak current results in some problems such as luminous flux saturation, thermal stress of the junction, etc. Therefore, it is necessary to minimize the peak value of the LED driving pulsating current. This paper deal with the design considerations of the newly proposed electrolytic capacitor-less single stage power converter to minimize the pulsating peak LED driving current. The usefulness of the proposed scheme is verified through the experimental results with 48W LED driving power converter.