US 11,749,354 B2
Systems and methods for non-parametric PV-level modeling and read threshold voltage estimation
Fan Zhang, Fremont, CA (US); Aman Bhatia, Los Gatos, CA (US); and Jianqing Chen, San Jose, CA (US)
Assigned to SK hynix Inc., Gyeonggi-do (KR)
Filed by SK hynix Inc., Gyeonggi-do (KR)
Filed on Jul. 13, 2021, as Appl. No. 17/374,750.
Prior Publication US 2023/0027191 A1, Jan. 26, 2023
Int. Cl. G11C 7/00 (2006.01); G11C 16/26 (2006.01); G11C 16/10 (2006.01); G11C 11/56 (2006.01); G06N 3/08 (2023.01); G06N 3/04 (2023.01); G06F 11/10 (2006.01); G11C 16/04 (2006.01); G11C 16/34 (2006.01)
CPC G11C 16/26 (2013.01) [G06N 3/04 (2013.01); G06N 3/08 (2013.01); G11C 11/56 (2013.01); G11C 16/10 (2013.01); G06F 11/1068 (2013.01); G11C 16/0483 (2013.01); G11C 16/3459 (2013.01)] 14 Claims
OG exemplary drawing
 
1. A memory system comprising:
a memory device including a plurality of cells; and
a controller configured to:
generate multiple optimal read threshold voltages corresponding to multiple sets of two cumulative distribution function (CDF) values, respectively;
perform read operations on the cells using a plurality of read threshold voltages;
generate cumulative mass function (CMF) samples based on the results of the read operations;
receive first and second CDF values, selected from among a plurality of CDF values, each CDF value corresponding to each CMF sample; and
estimate an optimal read threshold voltage corresponding to the first and second CDF values, among the multiple optimal read threshold voltages.