A Low-Voltage Charge Pump with High Pumping Efficiency

A low voltage charge pump with high pumping efficiency is proposed in this paper. To get high pumping efficiency, the proposed circuit uses 2 branches cross coupled structure. To eliminate the body effect and threshold voltage drops, PMOS transistors are used as Charge Transfer Switch (CTS). The inverters below and above the CTS PMOS for controlling the gate of CTS PMOS properly. Undesired charge transfer flows higher voltage node voltage to lower voltage node is removed as the NMOS transistor and PMOS transistor below and above the CTS PMOS turn off during the clock transition. Furthermore, the time when those NMOS transistor and PMOS transistor are both off is short and due to the cross coupled wiring, the fast gate control would be able to made by present and previous stage. So that the cross coupled CTS charge pump has higher pumping efficiency than conventional circuits. The simulation results show that the proposed circuit's performance is better than other circuits.