Design and realization of a switched-capacitor AC-DC converter with a low output-voltage ripple

An AC-DC converter using a new switched-capacitor (SC) transformer and its design are presented. The maximum voltage of capacitors is 1/n times that of a capacitor- input-type rectifier circuit, where n is the number of charge-transfer capacitors. The output voltage ripple is small, since the equivalent smoothing capacitor value is n times that of conventional SC transformers (series-parallel switching type). Using the design method presented, a test circuit was designed. The experimental results of the test circuit show that the efficiency of the SC transformer is very high (95%) and the maximum output power is 40 W.<>