Non-volatile memory device with threshold voltage control function
First Claim
1. An electrically erasable and programmable non-volatile memory device comprising:
- a plurality of erase unit areas each including a plurality of non-volatile memory cell transistors which are simultaneously selected in an erase operation;
a plurality of output regulating value storing sections provided corresponding to the respective erase unit areas, of storing output regulating values of the respective erase unit areas in a non-volatile manner;
a voltage generating circuit of generating a voltage having a level required in an erase operation and a write operation with respect to each of the erase unit areas;
a voltage regulating circuit of regulating the level of the voltage generated in the voltage generating circuit based on a corresponding one of the output regulating values provided thereto;
a read determination circuit of performing determination with respect to data after an erase operation and a write operation with respect to each of the erase unit areas; and
a control circuit of operating in an erase operation and a write operation with respect to each of the erase unit areas.
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Accused Products
Abstract
Even when the number of rewrite operations varies among erase unit areas, the number of rewrite operations is improved for all of the erase unit areas. A flash EEPROM 100 comprises a trimming value storing area 130 of storing a trimming value corresponding to each erase unit area 120 included in a memory cell array 110. When an erase operation and a write operation are performed with respect to a certain erase unit area 120, a regulator circuit 150 converts a voltage boosted by a booster circuit 140 to a level corresponding to the trimming value for the erase unit area 120. When a read determination circuit 170 detects an abnormality as the number of rewrite operations is increased, the trimming value is updated to a value which causes the regulator circuit 150 to increase the output voltage.
85 Citations
23 Claims
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1. An electrically erasable and programmable non-volatile memory device comprising:
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a plurality of erase unit areas each including a plurality of non-volatile memory cell transistors which are simultaneously selected in an erase operation; a plurality of output regulating value storing sections provided corresponding to the respective erase unit areas, of storing output regulating values of the respective erase unit areas in a non-volatile manner; a voltage generating circuit of generating a voltage having a level required in an erase operation and a write operation with respect to each of the erase unit areas; a voltage regulating circuit of regulating the level of the voltage generated in the voltage generating circuit based on a corresponding one of the output regulating values provided thereto; a read determination circuit of performing determination with respect to data after an erase operation and a write operation with respect to each of the erase unit areas; and a control circuit of operating in an erase operation and a write operation with respect to each of the erase unit areas. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification