Conventional switched capacitor converters have an inherent drawback that their efficiency is much decreased as the output current is increased. This inherent drawback is due to a periodical forced charging and discharging operation in the internal switched capacitors accompanied by a large capacitor current, so that their efficiency can not be increased by decreasing its internal resistance. As a result, conventional switched capacitor converters have been limited to be used with a very small output current. To solve this problem we presented a novel switched capacitor converter topology that uses a resonant operation instead of the forced charging and discharging operation. Its advantage over a conventional switched capacitor converter is a high efficiency even in a high output current region. In this paper, the operation analysis and steady-state characteristics are described in detail for a double boost type switched capacitor converter, and they are confirmed by experiments. The output voltage control method by changing the switching frequency is presented and analyzed by simulation.