Abstract: The electrolytic capacitor is used as the energy storage element in the traditional LED power supply.

The life of electrolytic capacitor is short which limits the life of LED power supply. In order to improve the service

life of the power supply，a single-stage low switch stress structure was proposed on the basis of removing the

electrolytic capacitor。The auxiliary loop composed of resonant capacitor and switching tube was introduced to

depress the switch stress and realize zero voltage switching（ZVS），meanwhile the leakage inductance energy was

fed back and the overall efficiency of power supply was improved. The working principle of the topology was

analyzed. The modal analysis and parameter design were given. The feasibility of the single-stage low switch stress

LED power supply without electrolytic capacitor was verified by experimental prototype.

      Key words: single-stage structure；low switch stress；resonant capacitor；zero voltage switching（ZVS）；

electrolytic capacitor-less