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. 23, 1992
Filed:
Jul. 18, 1989
Andrew C Graham, Sunnyvale, CA (US);
Gazelle Microcircuits, Inc., Santa Clara, CA (US);
Abstract
In one embodiment, the threshold voltage of the electrostatic protection circuit is selectively raised above the power supply voltage by the inclusion of a plurality of serially connected diodes connected between the power supply voltage and a discharge reference rail. The serially connected diodes become forward biased when a voltage applied to the rail is above the power supply voltage by a voltage equal to the sum of the various voltage drops across the serially connected diodes. The various input pads of the integrated circuit are connected to an anode of an associated diode, wherein the cathode of the associated diode is connected to the discharge reference rail, rather than directly to V.sub.DD as in the prior art. The anodes of each of these diodes are also connected to the device to be protected within the integrated circuit. Thus, when a voltage applied to the input pad is approximately one diode drop above the discharge reference rail, the voltage at the input pad will be shunted to the power supply voltage generator through the serially connected diodes.