METHOD AND CIRCUIT FOR PROGRAMMING OF FLOATING-GATE MEMORY CELL BY USING SINGLE LOW-VOLTAGE POWER SUPPLY

摘要

PURPOSE: To inject hot carriers efficiently using a single low voltage power supply by applying required pumping up and pumping down voltages, respectively, to the drain and source of a floating memory cell. CONSTITUTION: A memory cell 10 comprises a floating gate 13, a control gate 14, a drain 12 and a source 11 and programmed with a drain-source voltage of 6V, for example. Voltage Vcc of a low voltage power supply having reference voltage Vss=0V is charged up by a charge pump circuit through a drain line 18 corresponding to the drain 12 of a selected cell 10 to produce a voltage VBL of 4.5V, for example, which is applied to the drain and a charge down voltage VSL of -1.5V, for example, is applied similarly to the source 11 through a source line 17. At the same time, a voltage VSUB lower than a voltage VSL for blocking forward bias is applied to a substrate. According to the arrangement, the cell 10 can be programmed by injecting hot carrier effectively using a single low voltage power supply.