Efficiency Theory of switched capacitors converter

Fabien Todeschini (1) , Philippe Benabes (2) , Christophe Planat (1)

1 ST-CROLLES - STMicroelectronics [Crolles]
2 E3S - Supélec Sciences des Systèmes

This paper reports on a theoretical study of the efficiency of a switched capacitor converter for autonomous sensors. The sensor is composed of an energy harvester (Solar cell), the electronic system (micro-controller, radio, temperature sensor, MEMS. . . ) and a battery. Based on our theory, we calculate this efficiency with respect to: the switching frequency, the capacitance values and the battery voltage. We present this using 3-D graphs. This theory is based on Ultra-Low-Power Embedded systems such as wireless sensors with photovoltaic harvesters operating in low-light conditions. In this case, the harvested energy from PV do not exceed a few tens of micro-watts, which forbids the use of "power-hungry" coil-based power converters. On the contrary, using switched capacitors converter is a better alternative for this kind of application. We here present a theoretical framework deriving the maximum efficiency achieved by a switched capacitor converter with respect to: the switching frequency, the capacitance value and the battery voltage.

Domains: Electronics; Micro and nanotechnologies/Microelectronics

Fabien Todeschini, Philippe Benabes, Christophe Planat. Efficiency Theory of switched capacitors converter. IMAPS 2013, Nov 2013, Tours, France. pp.CD-Rom. ⟨hal-00952251⟩