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:
Jun. 01, 1982
Filed:
Dec. 10, 1979
Colin W Edwards, Lightwater, GB;
Hughes Aircraft Company, Culver City, CA (US);
Abstract
A non-volatile semiconductor latch having at least one variable threshold FATMOS transistor in the cross-coupled latch branches. To accomplish non-volatile reading, the latch nodes (X.sub.1, X.sub.2) are briefly precharged positively so that when the precharging ends and the nodes descend towards the negative supply voltage, the FATMOS(s), by virtue of their varied thresholds, place the latch in its correct logic state dictated by an earlier non-volatile write operation. Precharging, by means of transistors Q.sub.7, Q.sub.8 in parallel with the complementary drivers or loads, and transistors Q.sub.9, Q.sub.10 in series with the drivers in the latch, negates the capacitive effects which can otherwise cause unpredictable non-volatile reading. It also enables non-volatile reading to occur independently from power switch-on--which was necessary with earlier non-volatile FATMOS-containing latches.