This paper presents a zero-current-switching, switched capacitor based step-up resonant converter and the resonant inverting step-down converter. A switched Capacitor based step-up resonant converter isused for the voltage conversion of the converters and the resonant inverting step-down converter is used wherein negative voltage is required.. By adding a different number of switched capacitor cells, different output voltage conversion ratios can be obtained with the switching capacitor technique. All the power devices including witches and diodes in the circuit are operated using zero-current switching technique to rectify uncontrollable current spike which usually exists for classical switched-capacitor convertors, electromagnetic interference and switching losses. A resonant tank is used to assist in zero-current switching hence the current spike, which usually exists for classical switched-capacitor can be eliminated. Both high-frequency operations and high efficiency are possible. The simulation results verify the operation and performance of the circuits.