Dual mode high voltage power supply for providing increased speed in programming during testing of low voltage non-volatile memories

Abstract

A dual mode high voltage power supply circuit using an external high voltage connected through an internal high voltage switch which determines whether the memory blocks of a non-volatile memory circuit are programmed in a first mode from an internal high voltage charge pump or are programmed in a second mode from an external high voltage power supply connected in parallel to the internal high voltage charge pump. When the dual mode high voltage power supply circuit is operating in the first mode using only its internal change pump high voltage, it operates in a low power, low-speed mode, programming only one or two bits at a time but allowing the charge pump area on the die to be small. When operating in the second mode, in which the external power supply high voltage is available, eight or more bits can be written to at the same time, thus allowing a fast programming mode without the need for increasing the size of the internal charge pump, thus eliminating the additional space and cost required to increase the die area.