| 摘要 |
<p>PURPOSE:To obtain a flash memory of which current consumption is small and erase time is shortened. CONSTITUTION:Four sub-arrays 1a, 1b, 1c and 1d constitute four groups G1, G2, G3 and G4 respectively at a first erase cycle. Erase pulses are successively applied to sub-arrays 1a, 1b, 1c and 1d of groups G1, G2, G3 and G4. Two sub-arrays 1a and 1b constitute the group G1 and two sub-arrays 1c and 1d constitute the group G2 at a second erase cycle. First of all, erase pulses are simultaneously applied to sub-arrays 1a and 1b constituting the group G1, next, erase pulses are simultaneously applied to sub-arrays 1c and 1d constituting the group G2. Four sub-arrays 1a, 1b, 1c and 1d constitute the group G1 on and after a third erase cycle. Erase pulses are simultaneously applied to sub- arrays 1a, 1b, 1c and 1d constituting the group G1.</p> |
