| 摘要 |
<p>PROBLEM TO BE SOLVED: To improve write-in accuracy of a non-volatile memory. SOLUTION: Write-in voltage VH is applied to specific bit cells constituting an EEPROM at the time of initialization of one chip microcomputer and every prescribed period of after that and it is made an erasing state, after that, an output of a sense amplifier 5 is discriminated by applying read-out voltage VL to the bit cell. When an output of the sense amplifier 5 is a logic value '0', as the movement of accumulated electrons from a floating gate of the bit cell to a gate is insufficient, write-in voltage VH is made high and an output of the sense amplifier is discriminated again. Write-in voltage VH when an output of the sense amplifier 5 is made a logic value '1' is selected as appropriate voltage for erasing an EEPROM.</p> |
