Switched positive/negative charge pump design using standard CMOS transistors

The most common approach used in the generation of on-chip high voltages are based on Dickson´s charge pump. In embedded and stand-alone designs of non-volatile memories, multiple charge pumps are utilised to generate both positive and negative voltages. Owing to high voltage drop across their terminals, high-voltage transistors are used to implement charge transfer function in many charge pump designs. The authors present a switchable charge pump design that utilises standard (low voltage) transistors to generate positive or negative high voltage based on the required mode of operation. Such design eliminates the need for multiple charge pumps, hence resulting in better utilisation of the available silicon area. Moreover, the use of standard transistors is shown to provide better performance/efficiency than designs that uses high-voltage transistors.