Resonant boost switched capacitor converter with high efficiency

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 some novel switched capacitor converter topologies that use a resonant operation instead of the forced charging and discharging operation. Their advantage over conventional switched capacitor converters 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.