Generation of a deeper negative voltage using charge-pump to reduce chip area and current consumption

Abstract

A charge pump with a programmable architecture generates a deeper negative voltage to reduce chip area requirements and lower current consumption at chip-level. A set of serially connected charge transfer switches are connected between an input node, that can be set at ground or other low voltage, and an output node providing the negative voltage. Stage capacitors each have one plate connected between a pair of the charge transfer switches and a second plate receiving one of a pair of non-overlapping clock signals having an amplitude of the charge pump supply level. The charge transfer switches receive control signals to be alternately on or off and, when off, the output of the charge transfer switch is shorted to its control gate. Different input voltage levels can be selected and used to pre-charge the control gate of the first of the charge transfer switches to provide different output nodes.