Texas Instruments Corporation

Mohammed A Hassan

Andrew M Love

Robert M Crosby

Clyde F Dunn

In a Flash memory unit, the storage of a logic signal in the memory cells is determined by performing a READ operation. The NORMAL READ operation requires that the floating gate store an amount of charge Q above which a logic &ldquo;0&rdquo; is identified and below which a logic &ldquo;1&rdquo; is identified as being stored in the memory cell. A second level of charge Q stored on the floating gate is used in a TEST READ operation. The stored charge Q is greater than the stored charge Q , but less than the charge stored on the floating gate as the result of a WRITE operation. The result of a TEST READ operation is compared with a NORMAL READ operation of a memory cell. When the logic state identified by the TEST READ operation and the NORMAL READ operation are not the same, the charge on the cell is determined to have decayed below a prescribed level and the memory cell is refreshed to the level that is present during a WRITE operation.

Growing community of inventors

Sugar Land, TX, United States of America

Mohammed A Hassan