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:
Sep. 06, 1994
Filed:
Apr. 13, 1993
Steve G Renfro, Boise, ID (US);
Gary R Gilliam, Boise, ID (US);
Micron Semiconductor, Inc., Boise, ID (US);
Abstract
This invention is a low-power circuit for detecting and latching the state of a fusible link. During a power-up sequence, the circuit makes a one time determination regarding the blown or unblown status of a fuse element. In one embodiment of the invention, the circuit comprises a fuse detect node which is coupled to power supply voltage (V.sub.cc) through a first IGFET and to ground through a second IGFET (which, in this embodiment, has more drive than the first) and the fuse element, respectively, when the fuse element is not severed. In another embodiment of the invention, the fuse detect node is coupled to ground through the second IGFET, and to power supply voltage (V.sub.cc) through the first IGFET (which, in this embodiment, has more drive than the second) and the fuse element, respectively, when the fuse element is not severed. During a first portion of the power-up sequence, both first and second IGFETs are rendered conductive, thus allowing the fuse detect node to reach equilibrium with respect to charge. The equilibrium charge state will depend on whether or not the fuse is severed or intact, and this charge state is reflected in a latched output. Once the output has been latched, whether in a low or high state, the first and second MOSFETs are rendered nonconductive during a second portion of the power-up sequence, thus isolating the fuse detect node from V.sub.cc and ground. The output is used to select or deselect a feature option or redundant circuit element.