The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 24, 1998
Filed:
Dec. 04, 1996
Shigenori Miyauchi, Tokyo, JP;
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Abstract
The storage device of the present invention comprises: an interface circuit, a memory comprising a plurality of block-erase type, nonvolatile memories, a control circuit for managing and controlling the memory, and an address conversion table. The control circuit searches for an erase block with an empty area and issues a command signal to the memory to cause the memory to apply voltage pulses to the selected erase block. The memory checks to determine whether or not the erase operation has been completed every time the voltage pulse is applied to the erase block, and if the erase operation has not been completed, the control unit issues another command signal to cause the memory to apply another voltage pulse to the erase block and thus determines the level of degradation of the erase characteristic of the erase block based on the number of voltage pulses applied to that erase block.