Patent ID: 8339187

Claim:
A charge pump comprising: a plurality of pump stages arranged in a sequence of pump stages, each pump stage including an output node and a first node; wherein at least one of the pump stages, N or a subset of the pump stages, N and one or more stages higher than N, in the sequence of pump stages, where N≧2, further comprises a transistor coupled to a previous pump stage in the sequence of pump stages to obtain a reference voltage corresponding to the previous pump stage to which the transistor is coupled; wherein the pump stage N or the subset of pump stages N and the one or more stages higher than N in the sequence of pump stages each further comprises a precharge circuit coupled to the output node of the corresponding pump stage in the sequence of pump stages; wherein the precharge circuit is different from the transistor; and wherein each said transistor discharges its corresponding pump stage in the sequence of pump stages via use of the corresponding reference voltage; and wherein the charge pump further comprises circuitry to help drive the charge pump during a low voltage condition, the circuitry including a voltage level shifter to drive a capacitance.