High-voltage management in single-supply CHE NOR-type flash memories

In a flash memory, a number of voltage levels different from V_DD are needed to perform the required operations (read, program, and erase) on the array cells. In the case of single-supply memory devices, voltages higher than V_DD as well as negative voltages, which are referred to as high voltages (HVs), must be produced on-chip. This paper aims at giving the reader an overview of how HVs are generated and managed in single-supply NOR-type flash memories programmed by channel hot-electron injection. Both schemes used for conventional (i.e., bilevel) memory devices and schemes designed to meet multilevel memory requirements are addressed.