To: Ausdauer who wrote (9877 ) 3/29/2000 9:25:00 AM From: Ron C Read Replies (1) | Respond to of 60323
New patents:-------------------------------------------------------------------------------- United States Patent 6,044,019 Cernea, et. al. Mar. 28, 2000 -------------------------------------------------------------------------------- Non-volatile memory with improved sensing and method therefor Abstract Floating gate memories such as EEPROM and flash EEPROM have the memory state of a memory cell thereof determined by sensing the conduction current of the cell. Inherent noise fluctuations in the conduction current during sensing are canceled out by averaging the sensing over a predetermined period of time. In one embodiment, as an integral part of the averaging process, the averaged conduction current is obtained directly as a digital memory state. Accuracy in sensing is therefore greatly improved by avoiding sensing noise with the current and avoiding having to resolve its memory state in the analog domain by comparison with another noisy reference current. In another embodiment, conventional sensing techniques are improved when sensing is made by comparison with a reference current by means of a symmetric, switched or non-switched capacitor differential amplifier. The improved sensing accuracy allows higher resolution of conduction states, thereby allowing a cell to store substantially more than one bit of information. -------------------------------------------------------------------------------- Inventors: Cernea; Raul-Adrian (Santa Clara, CA); Tang; Rushyah (San Jose, CA); Lee; Douglas (San Jose, CA); Wang; Chi-Ming (Fremont, CA); Guterman; Daniel (Fremont, CA). Assignee: SanDisk Corporation (Sunnyvale, CA). Appl. No.: 177,809 Filed: Oct. 23, 1998 Intl. Cl. : G11C 13/00 Current U.S. Cl.: 365/185.21; 365/185.2; 365/189.07; 365/189.09; 365/207 Field of Search: 365/185.21, 185.2, 189.09, 189.07, 207, 206, 149 -------------------------------------------------------------------------------- References Cited | [Referenced By] -------------------------------------------------------------------------------- U.S. Patent Documents 5,172,338 Dec., 1992 Mehrotra et al. 365/185 5,508,956 Apr., 1996 Campardo et al. 365/185.12 X Primary Examiner: Yoo; Do Hyun Attorney, Agent or Firm: Majestic, Parsons, Siebert & Hsue 19 Claims, 24 Drawing Figures --------------------------------------------------------------------------------