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:
Mar. 02, 2004
Filed:
Sep. 10, 2002
Bahram Fotouhi, Cupertino, CA (US);
Bahman Farzan, Mountain View, CA (US);
Saied Rafati, Saratoga, CA (US);
Exar Corporation, Fremont, CA (US);
Abstract
A protection circuit for a transmission gate having a PMOS transmission gate transistor and an NMOS transmission gate transistor coupled between a core circuit and an I/O pad. Biasing transistors are coupled to gates of the NMOS and PMOS transmission gate transistors to turn them on during normal operation. A protection circuit will turn off the NMOS and PMOS transmission gate transistors when the voltage at the pad exceeds the supply voltage by more than a threshold amount. This protection circuit includes a first protection transistor coupled between the gates of the biasing transistors and the pad to turn the biasing transistors off when the voltage on the pad exceeds the supply voltage by more than the threshold amount.