The folding dickson converter: A step towards fully integrated wide input range capacitive DC-DC converters

Abstract

This paper presents a novel approach to wide input range capacitive DC-DC converters. The star connected Dickson converter is used, not only for its low bottom plate voltage swing and efficient use of switches, but also for its very regular structure. This regular structure allows it to operate as a folding Dickson converter, implementing several conversion ratios, as well as reusing all of its flying capacitance. Folding is achieved by changing the phases of the switches, and keeping certain flying switches on in both phases, virtually lumping flying capacitors together. This last fact, along with the other benefits of the Dickson converter, makes it a good candidate for full integration. The flying switches of the converter are driven from their own converter, using an adapted bootstrapped converter which uses the intrinsic operation of the Dickson converter to copy the voltage of the flying capacitors and boost it by Vout.