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:
Nov. 29, 2005
Filed:
Mar. 14, 2002
Wai Cheong Chan, Sunnyvale, CA (US);
Khusrow Kiani, Oakland, CA (US);
Wai Cheong Chan, Sunnyvale, CA (US);
Khusrow Kiani, Oakland, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
The invention enables the performance of the input and output stages of an I/O circuit to be modified after an IC is manufactured. In one embodiment, the I/O circuit includes an output driver, programmable pre-driver, programmable Schmitt-trigger input buffer, control circuit and logic circuit. Depending on the number of pull-up and pull-down MOS transistor pairs or 'cells' that are enabled in the programmable pre-driver and their different sizes, the overall sizing ratio imbalance between the transistors may be programmed. In particular, the high and low trip points for activation of the output driver is related to an imbalance in the overall sizing ratio of transistors enabled in the programmable pre-driver. This affects the timing characteristics of the output driver.