Circuits for prevention of reverse leakage in Vth-cancellation charge pumps

摘要

Techniques are presented to reduce reversion leakage in charge pump circuits. The exemplary circuit is a charge pump of the voltage doubler type, where the output of each leg is supplied through a corresponding output transistor. An auxiliary charge pump is used to supply the gates of the output transistors in order to cancel the threshold voltage of these output transistors. To reduce reverse leakage back through the output transistors, in each leg of the charge pump a switch is connected between the gate of the output transistor and the output level of the leg so the these levels can be shorted when that particular is not supplying the pump's output.