To address the issues of reduced lifespan and compromised reliability in LED driver power supplies caused by electrolytic capacitors

an integrated flyback two-switch electrolytic capacitor-less LED driver circuit topology was proposed

which integrates a flyback converter

a Buck-Boost converter and a Buck converter

simplifies the circuit structure

and achieves a high power factor

low frequency of the output current ripple suppression and constant current control. The Buck-Boost converter was used to transfer the excess energy from the AC side to the storage capacitor of the auxiliary circuit

and the Buck converter was used to compensate for the insufficient energy on the output side

which balances the difference between the input alternating power and the output power

and reduces the capacity of the storage capacitor

thus allowing the circuit to be electrolytic capacitor-less by using small-capacity film capacitors instead of electrolytic capacitors. The working principle of the proposed circuit topology was analysed in detail

the control strategy applicable to this topology was proposed

and the design method of the main parameters of the circuit was given. Finally

a 36 W experimental prototype was fabricated to verify effectiveness of the proposed circuit topology and its control strategy.