This talk introduces on-chip voltage converter and dynamic voltage scaler circuits targeted at ultra low power applications with low duty ratio such as IoT sensors.

Due to excessive size of on-chip inductors, voltage converters based on switched capacitor are in general considered as more practical approaches to on-chip designs than inductor-based DC-DC converters. 

In applications with low duty ratio, the charging cycle of the switched capacitor voltage converters account for significant energy waste, while its transition to sleep mode often leaves its unused energy lost through leakage current over a long sleep period.

We present new structure and mechanism called split charging and energy recycling voltage converter to minimize such energy waste.

We also introduce a dynamic voltage scaler architecture using DAC with efficient recharge. We discuss preliminary simulation results with MEMS switches, which demonstrate that the reduced switch resistance can provide additional energy savings.