Power efficient reconfigurable charge pump for micro scale energy harvesting

One of the key challenges in micro scale energy harvesting system is that the output voltages produced by the tiny transducers are very low (0-0.4V). Therefore a charge pump(CP) with high voltage step up ratio is essential to boost the voltage, and charge an energy buffer for storage. Conventional Linear and Fibonacci charge pumps have better current driving capabilities at higher and lower voltage ranges respectively. This paper presents a reconfigurable charge pump topology which utilizes merits of both Linear and Fibonacci charge pumps for micro scale energy harvesting applications with wider range of input voltages. Through this approach we are extending lowest operating voltage by 50mv as compared to a standalone linear charge pump. The proposed charge pump has been designed with UMC 180nm technology and the circuit simulations demonstrate a wider range of input voltages as compared to conventional charge pumps. Through this we are able to extend lower input voltage limit from a value of 230 mV to 180 mV.