An Input Capacitor-Less Boost Converter With Variation-Tolerant MPPT Circuit for Thermal Energy Harvesting

Abstract

This paper presents an input capacitor-less boost converter with a maximum power point tracking (MPPT) circuit for thermal energy harvesting applications. The MPPT circuit is implemented by a fractional open-circuit voltage method with a feedback control circuit to adjust switching frequency of the boost converter until the output power is maximized. The use of a fractional open-circuit voltage method with feedback mechanism make the MPPT highly robust against process variation and component tolerances. Moreover, due to an input capacitor-less feature, the MPPT circuit can fast track the maximum power point (MPP) when input voltage varies. The converter is designed using a 130 nm CMOS technology and uses a thermoelectric generator (TEG) as an input voltage source. Simulation results show a peak efficiency of 68% at 100 mV input voltage and can provide a maximum output voltage of 2.8 V.