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1. (WO2018080644) DYNAMIC READ FOR A NAND MEMORY

Pub. No.:    WO/2018/080644    International Application No.:    PCT/US2017/050568
Publication Date: Fri May 04 01:59:59 CEST 2018 International Filing Date: Fri Sep 08 01:59:59 CEST 2017
IPC: G11C 11/56
G11C 16/26
G11C 16/32
G06F 11/10
Applicants: SANDISK TECHNOLOGIES LLC
Inventors: ALROD, Idan
SHARON, Eran
EYAL, Alon
PANG, Liang
MEKHANIK, Evgeny
Title: DYNAMIC READ FOR A NAND MEMORY
Abstract:
Techniques are provided for improving the accuracy of read operations of memory cells, where the threshold voltage of a memory cell can shift depending on when the read operation occurs. A memory cell is sensed by discharging a sense node into a bit line and detecting an amount of discharge at two sense times relative to a trip voltage. A bit of data is stored in first and second latches based on the two sense times, to provide first and second pages of data. The pages are evaluated using parity check equations and one of the pages which satisfies the most equations is selected. In another option, word line voltages are grounded and then floated to prevent coupling up of the word line. A weak pulldown to ground can gradually discharge a coupled up voltage of the word lines.