Sandisk Technologies Inc.

Jong Park

Man Lung Mui

Seungpil Lee

Fanglin Zhang

Yingda Dong

Gerrit Jan Hemink

Ken Oowada

Hao Nguyen

Alexander Chu

A non-volatile storage system that performs programming and reading processes. The programming process includes coarse/fine programming and verify operations. Programming is verified by testing for two different threshold voltage levels while applying the same voltage level to the control gate of a memory cell by testing for current levels through the memory cells and adjusting the current levels tested for based on current temperature such that the difference between the two effective tested threshold voltage levels remains constant over temperature variation.

Temperature based compensation during verify operations for non-volatile storage

In a non-volatile memory system, a voltage generator provides a voltage to a gate of a voltage-setting transistor which is used in a sense circuit to set an initial voltage at a sense node. At the end of a sense period, a final voltage of the sense node is compared to a trip point, which is the threshold voltage of a voltage-sensing transistor. To account for temperature variations and manufacturing process variations, the voltage generator includes a transistor which is matched to the voltage-setting transistor, and a transistor which is matched to the voltage-sensing transistor. As a result, a voltage swing between the initial voltage and the trip point is constant, even as the initial voltage and trip point vary. In a particular implementation, the voltage generator uses a cascode current mirror circuit, and receives a reference current from a band gap voltage circuit.

Voltage generator to compensate sense amplifier trip point over temperature in non-volatile memory

Growing community of inventors

Campbell, CA, United States of America

Jong Park