An ultra-low-power boost converter for micro-scale energy scavenging

This paper presents an ultra-low-power boost converter for indoors photovoltaic energy harvesting applications. The boost converter, working in the discontinuous conduction mode (DCM), utilizes an active diode (AD) technique to avoid negative current flowing in the inductor and a control technique that allows supplying dual output voltage levels with sufficient power. The AD is implemented using a level-sensitive clocked comparator that is driven by the system clock while consuming 350nA only. The system clock is chosen as a compromise between required speed of the comparator, switching losses, and size of external inductor. Post-layout simulation results show an overall efficiency of 76.9% for an input power of 160μW while providing two outputs at 1.2V and 3V in 130nm CMOS technology.