Mosys, Inc.

Chee T Chua

Kameswara K Rao

Jawji Chen

J Eric Ruetz

Stephen Fung

Vithal Rao

Da-Guang Yu

A method for selectively refreshing data in a nonvolatile memory array based on failure type detected by an error correction code. If the page is determined to be error-free, no refresh operation takes place. Otherwise, if single-error words on a page contain erased and programmed bit errors, then a refresh operation, consisting of an erase and program, takes place. The erase operation is skipped if single-error words on a page solely contain a program failure.

Automatic refresh for improving data retention and endurance characteristics of an embedded non-volatile memory in a standard CMOS logic process

A memory circuit for holding a single binary value. A first bit cell holds one of a logical high value and a logical low value, and a second bit cell also holds one of a logical high value and a logical low value. Circuitry is provided for placing a logical high value in the first bit cell when the binary value in the memory circuit is to be a logical high value, and circuitry is provided for placing a logical high value in the second bit cell when the binary value in the memory circuit is to be a logical low value. In this manner, a logical high value exists within the memory circuit, whether the single binary value within the memory circuit is a logical high value or a logical low value. The difference between the two values of the binary value is which of the two bit cells holds the logical high value. Thus, this memory circuit can be sensed without the use of a sense amplifier.

Two bits per cell non-volatile memory architecture

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Fremont, CA, United States of America

Chee T Chua