A folding dickson-based fully integrated wide input range capacitive DC-DC converter achieving Vout/2-resolution and 71% average efficiency

This paper presents a fully integrated capacitive DC-DC converter with a wide input voltage range. The folding Dickson converter is used to implement four discrete voltage conversion ratios, capable of operating over a wide input voltage range. A subconverter is added, enabling four additional voltage conversion ratios, improving the input voltage resolution from Vout to 1 Vout. This way, the extra conversion ratios increase the overall efficiency, and at the same time reduce output ripple specifications. Implementing this additional converter at the end of the Dickson cascade reduces the complexity of driving the extra power train switches. This improved folding Dickson converter achieves an average efficiency above 70% at maximum output power, and operates over an input voltage range of 2.5-8V for an output voltage of 1.2V. The converter has been implemented and validated in a standard 90nm technology.