A threshold voltage start-up (TVS) scheme for a boost converter is presented. The TVS converter could start up at the average threshold voltage of the fabrication process, and converts a fluctuating (energy harvesting) input of 0.2V to 0.9V to a regulated output of 1.2V. It operates in discontinuous conduction mode with peak current control (and thus operates with pulse frequency modulation) to reduce switching loss at light loads. The converter was designed with an AMS 0.35μm CMOS process and measured 675μm×615μm. The maximum efficiency is 83% at an output current of 1mA with an input voltage of 0.9V.

Abstract-An integrated single-inductor dual-input dual-output (SI DIDO) boost converter for energy harvesting applications was designed in a 0.35μm CMOS process. It provides two regulated output voltages for the load and the charge storage device, and two sources, the energy harvesting source and the charge storage device, are multiplexed to serve as the input. The implementation has several special features. (1) The input power MUX is driven by an internal charge pump for a larger gate drive to save area. (2) The power stage is implemented with an active diode core to eliminate gate drive circuitry. (3) A 1:7 timeslot scheduling with a fixed peak inductor current is adopted to deliver energy to the two outputs with a large difference in load currents. The proposed converter could operate at 1V with up to 85% efficiency at 200mW.