Modified N:1 Switched Capacitor Converter with Reduced Capacitor DC Bias Voltage for High Power Density

Switched capacitor converters require large capacitors due to the burden of high peak currents, which imposes a limitation on the minimum volume of passive components. This paper structurally proposes a new topology that reduces the DC voltage stress of capacitors, aiming to decrease stored energy and improve passive component volume. It is derived by modifying the connection state of the flying capacitors in the conventional Dickson converter. A consistent derivation method is applied to generalize it for a voltage conversion ratio of N:1. The improvement in passive component volume due to the reduction in DC voltage stress is confirmed through the output impedance analysis. Furthermore, the theoretical decrease of output impedance is derived through an equivalent circuit analysis based on the switch connection states. The proposed topology is experimentally verified with 48 V input to 8 V, 20 A output prototype. A full load efficiency of 96 %, which is 0.8% higher than that of the conventional Dickson converter, was achieved, with a 43.3 % reduction in passive component volume.