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:
Dec. 22, 1992
Filed:
Jun. 03, 1991
Ramon Co, Trabuco Canyon, CA (US);
Kwok Fai Lee, Irvine, CA (US);
Kenneth W Ouyang, Huntington Beach, CA (US);
Western Digital Corporation, Irvine, CA (US);
Abstract
An integrated circuit electrostatic discharge (ESD) protection circuit employs a capacitor and a zener diode to trigger a thick oxide ESD shunt field effect transistor (FET). When an ESD induced voltage at an input or output node reaches the turn-on voltage determined by the zener diode breakdown voltage, the shunting transistor is turned on by current capacitively coupled to the base of the parasitic bipolar transistor inherently formed in the thick oxide FET. The parasitic bipolar transistor is turned on in its saturated mode, substantially shorting the node to ground. At the end of the ESD event when the ESD induced current is no longer sufficient to keep the shunting transistor in its saturated mode, the shunting transistor turns off and the ESD protection circuit returns to its off mode, monitoring the input or output node for the occurrence of another ESD event.