A low start-up voltage charge pump for energy harvesting applications

Abstract

Threshold voltage cancellation (Vt cancellation) scheme is applied to cancel the threshold drop associated with the diode-connected device and improve charge pump performance. Applying this scheme depends on generating control signals from the next stage so it cannot be applied on the output stage. In this paper Vt cancellation is applied for the output stage of modified Pelliconi pump. This is done by adding an extra circuit that establishes the controlling signals necessary for the auxiliary circuit of the output stage. This modification in the output stage leads to increasing the whole pump power efficiency and voltage gain. Also the pump output equivalent resistance is improved. The proposed charge pump is more suitable for energy harvesting applications due to its ability to give more gain at low voltage levels.