The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 18, 2017
Filed:
Jun. 24, 2016
Sandisk Technologies Llc, Plano, TX (US);
Chris Yip, Saratoga, CA (US);
Philip Reusswig, Mountain View, CA (US);
Nian Niles Yang, Mountain View, CA (US);
Grishma Shah, Milpitas, CA (US);
Abuzer Azo Dogan, San Jose, CA (US);
Biswajit Ray, Mountain View, CA (US);
Mohan Dunga, Santa Clara, CA (US);
Joanna Lai, San Jose, CA (US);
Changyuan Chen, San Ramon, CA (US);
SanDisk Technologies LLC, Plano, TX (US);
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. In one aspect, read voltages are set and optimized based on a time period since a last sensing operation. A timing device such as an n-bit digital counter may be provided for each block of memory cells to track the time. The counter is set to all 1's when the device is powered on. When a sensing operation occurs, the counter is periodically incremented based on a clock. When a next read operation occurs, the value of the counter is cross-referenced to an optimal set of read voltage shifts. Each block of cells may have its own counter, where the counters are incremented using a local or global clock.