| 摘要 |
PURPOSE: A circuit for writing to an EPROM(Erasable Programmable Read Only Memory) is provided to perform a stable write operation against variation of boost voltages. CONSTITUTION: The device includes a cell array(100), a word-line decoder(150), a bit-line decoder(160), a source voltage sensor(140), a decoding part(130), power switches(120-122), a voltage dropping part(110) and N-MOS(Metal Oxide Semiconductor) transistors(NM1-NM16). According to a write signal(Wpgm), the word-line decoder(150) decodes 8-bit address(ADD£7:0|) and enables selected word lines. According to the write signal(Wpgm), the bit-line decoder(160) decodes 8-bit address(ADD£7:0|) and enables selected bit lines. The source voltage sensor(140) senses a level of a boost voltage(VPP) and generates sensed signals(A,B). The decoding part(130) decodes the sensed signals(A,B). According to an output signal from the decoding part(130) and the write signal(Wpgm), the power switches(120-122) supply the boost voltage(VPP). According to output signals from the power switches(120-122), the voltage dropping part(110) drops the boost voltage(VPP). According to output signals from the bit-line decoder(160), the N-MOS(Metal Oxide Semiconductor) transistors(NM1-NM16) supplies the dropped voltage to the cell array(100).
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