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:
Apr. 05, 1994
Filed:
Aug. 21, 1991
Applicant:
Inventor:
William E Miller, Los Gatos, CA (US);
Assignee:
National Semiconductor Corporation, Santa Clara, CA (US);
Primary Examiner:
Int. Cl.
CPC ...
H02H / ;
U.S. Cl.
CPC ...
361 91 ; 361111 ; 361 56 ; 257356 ;
Abstract
An electrostatic discharge ('ESD') protection circuit for use in CMOS I.C. devices provides a low voltage path to and from each input and output ('I/O') pad and power pad by using the wide, low resistance metal VCC and Vss rings and parasitic bipolar transistors configured as three terminal devices at each I/O and power pad. The present invention also provides a clamp, between the VCC and VSS rings, capable of being rapidly switched into the conducting state during an ESD event so as to shunt excess bias current that could otherwise damage reverse biased junctions during an ESD event.