Low Input Voltage Charge Pump for Thermoelectric Energy Harvesting Applications in 65nm CMOS Technology

Ambient energy harvesting, especially thermoelectric energy, typically produces power in the microwatts range which is essentially not enough to directly start most integrated circuit loads. Voltage boosting schemes are critical to making low voltage energy harvesting feasible. A charge pump is an effective voltage boosting technique with no off-chip components. This study presents the design of a charge pump for thermoelectric energy harvesting that can start up at low input voltages. Utilizing Vth cancellation techniques, this charge pump topology is redesigned from the multi-stage conventional cross-coupled charge pump architecture to increase efficiency. The designed charge pump can produce an output of 2V with an input of 0.4V. And a maximum of 57% power conversion efficiency was reached by the proposed charge pump. The designed on-chip charge pump was implemented using 65nm CMOS technology, and its operations were verified using the Synopsys tools.