Low-voltage eeprom using charge-pumped word lines

Abstract

A Low-voltage Electrically Erasable, Electrically Programmable Read Only Memory (EEPROM) and a method for reading memory cells in the EEPROM. During a read operation address input is provided to an address latch and edge detector, which supplies a changed address signal to a charge-sharing word line voltage generator, supplies word line address signals to a word line address decoder, and supplies bit line address signals to a bit line address decoder and sense amplifier circuit. The word line address decoder provides a positive voltage from a positive voltage source to a selected word line in the memory array and provides a voltage that is negative with respect to ground to deselected word lines. The bit line address decoder and sense amplifier circuit grounds selected source bit lines and senses drain to source current to read the memory cells. The charge-sharing word line voltage generator and charge-sharing bit line voltage generator use a plurality of charge pump circuits and capacitors to store and share charge with the word lines. The EEPROM has a reduced erased voltage threshold range by extending the erase time during erase operations.