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. 21, 2000
Filed:
Jun. 01, 1999
David P Morrill, Portland, ME (US);
Fairchild Semiconductor Corp., South Portland, ME (US);
Abstract
A CMOS-based bus-hold circuit having overvoltage tolerance. The bus-hold circuit of the present invention includes, in addition to conventional input and latching inverters, a sense circuit and an arbiter circuit designed in combination to block overvoltage events from powering the latching inverter. The sense circuit includes a comparator designed to compare the potential of a standard high-potential power supply rail to the potential associated with a signal applied to the bus-hold circuit's input node. The higher of those two potentials is used to activate the arbiter circuit that in turn couples the higher of those two signals to a pseudo high-potential power rail. The pseudo high-potential power rail is used to supply power to the latching inverter such that the latching inverter will not be activated during overvoltage conditions, particularly when the circuit is in its high-impedance state. The bus-hold circuit may be similarly designed to establish an undervoltage tolerance as well.