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. 08, 1999
Filed:
Feb. 19, 1997
Luis Sergio Boluna, Sunnyvale, CA (US);
Tuong Hai Hoang, San Jose, CA (US);
Tony S Lo, San Jose, CA (US);
Larry W DeClue, Saratoga, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A circuit for protecting an interface cable driver and the circuitry attached to the driver from electrical overstress damage, such as that which may arise from an electrostatic discharge. The protection circuit includes a sensing element, typically a field oxide transistor, which is used to sense when an EOS transient raises the input/output voltage above the normal operating range. The sensing element is configured to change logic state when the transient reaches a predetermined threshold level. The change in state is used as a feedback path to turn on the interface driver transistor connected to ground and turn off the interface driver transistor connected to the power supply. The interface driver transistor connected to ground then acts to shunt away the transient, preventing damage to the driver and internal circuitry.