Writable tracking cells

Details Writable tracking cells Writable tracking cells

2005-03-29

2005-03-29

Phung, Anh (Department: 2824)

Static information storage and retrieval

Floating gate

Multiple values

C365S185200

Reexamination Certificate

active

06873549

ABSTRACT:
The present invention presents several techniques for using writable tracking cells. Multiple tracking cells are provided for each write block of the memory. These cells are re-programmed each time the user cells of the associated write block are written, preferably at the same time, using the same fixed, global reference levels to set the tracking and user cell programmed thresholds. The threshold voltages of the tracking cells are read every time the user cells are read, and these thresholds are used to determine the stored logic levels of the user cells. In one set of embodiments, populations of one or more tracking cells are associated with different logic levels of a multi-state memory. These tracking cell populations may be provided for only a subset of the logic levels. The read points for translating the threshold voltages are derived for all of the logic levels based upon this subset. In one embodiment, two populations each consisting of multiple tracking cells are associated with two logic levels of the multi-bit cell. In an analog implementation, the user cells are read directly using the analog threshold values of the tracking cell populations without their first being translated to digital values. A set of alternate embodiments provide for using different voltages and/or timing for the writing of tracking cells to provide less uncertainty in the tracking cells' final written thresholds.

REFERENCES:
patent: 4802166 (1989-01-01), Casagrande et al.
patent: 4949307 (1990-08-01), Campardo
patent: 4974206 (1990-11-01), Iyama et al.
patent: 5010518 (1991-04-01), Toda
patent: 5043940 (1991-08-01), Harari
patent: 5081610 (1992-01-01), Olivo et al.
patent: 5095344 (1992-03-01), Harari
patent: 5142496 (1992-08-01), Van Buskirk
patent: 5163021 (1992-11-01), Mehrotra et al.
patent: 5172338 (1992-12-01), Mehrotra et al.
patent: 5198997 (1993-03-01), Arakawa
patent: 5267202 (1993-11-01), Dallabora et al.
patent: 5270979 (1993-12-01), Harari et al.
patent: 5287315 (1994-02-01), Schreck et al.
patent: 5293345 (1994-03-01), Iwahashi
patent: 5311466 (1994-05-01), Natale et al.
patent: 5313421 (1994-05-01), Guterman et al.
patent: 5315541 (1994-05-01), Harari et al.
patent: 5386388 (1995-01-01), Atwood et al.
patent: 5408148 (1995-04-01), Pascucci et al.
patent: 5418752 (1995-05-01), Harari et al.
patent: 5430859 (1995-07-01), Norman et al.
patent: 5434825 (1995-07-01), Harari
patent: 5453955 (1995-09-01), Sakui et al.
patent: 5463586 (1995-10-01), Chao et al.
patent: 5493533 (1996-02-01), Lambrache
patent: 5532623 (1996-07-01), Advani et al.
patent: 5532962 (1996-07-01), Auclair et al.
patent: 5537358 (1996-07-01), Fong
patent: 5541886 (1996-07-01), Hasbun
patent: 5546351 (1996-08-01), Tanaka et al.
patent: 5602987 (1997-02-01), Harari et al.
patent: 5608676 (1997-03-01), Medlock et al.
patent: 5629892 (1997-05-01), Tang
patent: 5642308 (1997-06-01), Yoshida
patent: 5684739 (1997-11-01), Takeuchi
patent: 5687114 (1997-11-01), Khan
patent: 5712189 (1998-01-01), Plumton et al.
patent: 5754475 (1998-05-01), Bill et al.
patent: 5774395 (1998-06-01), Richart et al.
patent: 5787038 (1998-07-01), Park
patent: 5818759 (1998-10-01), Kobayashi
patent: 5828601 (1998-10-01), Hollmer et al.
patent: 5828602 (1998-10-01), Wong
patent: 5847996 (1998-12-01), Guterman et al.
patent: 5886927 (1999-03-01), Takeuchi
patent: 5889702 (1999-03-01), Gaultier et al.
patent: 5912838 (1999-06-01), Chevallier
patent: 5936888 (1999-08-01), Sugawara
patent: 5936906 (1999-08-01), Tsen
patent: 5946238 (1999-08-01), Campardo et al.
patent: 5966330 (1999-10-01), Tang et al.
patent: 5973959 (1999-10-01), Gerna et al.
patent: 5982662 (1999-11-01), Kobayashi
patent: 6002614 (1999-12-01), Banks
patent: 6016272 (2000-01-01), Gerna et al.
patent: 6016276 (2000-01-01), Fuji
patent: 6021068 (2000-02-01), Miki et al.
patent: 6028791 (2000-02-01), Tanaka
patent: 6055187 (2000-04-01), Dallabora et al.
patent: 6094368 (2000-07-01), Ching
patent: 6103573 (2000-08-01), Harari et al.
patent: 6141261 (2000-10-01), Patti
patent: 6154392 (2000-11-01), Patti
patent: 6219277 (2001-04-01), Devin et al.
patent: 6222762 (2001-04-01), Guterman et al.
patent: 6314014 (2001-11-01), Lowrey et al.
patent: 6317363 (2001-11-01), Guterman et al.
patent: 6373767 (2002-04-01), Patti
patent: 6418054 (2002-07-01), Hollmer
patent: 6426893 (2002-07-01), Conley et al.
patent: 6512263 (2003-01-01), Yuan et al.
patent: 0814480 (1997-12-01), None
patent: 0936627 (1999-08-01), None
patent: 0961285 (1999-12-01), None
patent: 0978844 (2000-02-01), None
patent: 0987715 (2000-03-01), None
patent: 2778012 (1998-04-01), None
patent: 4291940 (1992-10-01), None
patent: 7287984 (1995-01-01), None
patent: 9139089 (1997-05-01), None
patent: 9219095 (1997-08-01), None
patent: 9270195 (1997-10-01), None
patent: WO 9803978 (1998-01-01), None
patent: 10134587 (1998-05-01), None
patent: 11066875 (1999-03-01), None
patent: 11274437 (1999-10-01), None
patent: 2000057783 (2000-02-01), None
patent: 97029866 (1997-06-01), None
patent: WO 9520224 (1995-07-01), None
patent: WO 9908284 (1999-02-01), None
patent: WO 00 42615 (2000-07-01), None
“Communication Relating to the Results of the Partial International Search”, From International application No. PCT/US01/30123, dated Sep. 20, 2002, 9 pages.

Affiliated with

Also associated with

Rating

Writable tracking cells does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Writable tracking cells, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Writable tracking cells will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3452441