US 8,305,811 B2 · Flash memory device and method of reading data

Abstract

A flash memory device and method of reading data are disclosed. The method includes; performing a test read operation directed to test data stored in a memory cell array of the flash memory device by iteratively applying a sequence of test read retry operations, wherein each successive test read retry operation uses a respectively higher test read voltage level than a preceding test read retry operation, until one test read retry operation in the sequence of test read retry operations successfully reads the test data using a minimum test read retry voltage associated with the one test read retry operation, setting an initial read voltage for the flash memory device equal to the minimum test read retry voltage, and thereafter performing a normal read operation directed to user data stored in the memory cell array by iteratively applying a sequence of read retry operations, wherein an initial read retry operation in the sequence of read retry operations uses the initial read voltage.

Claims18

Dependent claims

A method of reading data from a flash memory device, the method comprising:

performing a test read operation directed to test data stored in a memory cell array of the flash memory device by iteratively applying a sequence of test read retry operations, wherein each successive test read retry operation uses a respectively higher test read voltage level than a preceding test read retry operation, until one test read retry operation in the sequence of test read retry operations successfully reads the test data using a minimum test read retry voltage associated with the one test read retry operation;
setting an initial read voltage for the flash memory device equal to the minimum test read retry voltage;
and thereafter
performing a normal read operation directed to user data stored in the memory cell array by iteratively applying a sequence of read retry operations, wherein an initial read retry operation in the sequence of read retry operations uses the initial read voltage.

1 more element

A flash memory device comprising:

a memory cell array comprising a set data region, a test block, and a user data region;
a controller configured to control the execution of a normal read operation directed to user data stored in the user data region, and execution of a test read operation directed to test data stored in the test block,
wherein execution of the normal read operation comprises iteratively applying a sequence of read retry operations, and
execution of the test read operation comprises iteratively applying a sequence of test read retry operations, such that each successive test read retry operation uses a respectively higher test read voltage level than a preceding test read retry operation, until one test read retry operation in the sequence of test read retry operations successfully reads the test data using a minimum test read retry voltage associated with the one test read retry operation;
and
a read retry start voltage setting unit configured to store the minimum test read retry voltage as an initial read voltage;
wherein the sequence of read retry operations comprises the initial read retry operation through an Nth read retry operation, and each read retry operation in the sequence of read retry operations uses a respectively higher read voltage ranging from the initial read voltage having a lowest level to an Nth read voltage having a highest level.

4 more elements

Dependencies are inferred from the claim text.

Flash memory device and method of reading data

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Flash memory device and method of reading data

Life of this patent

Abstract

Claims18