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:
Dec. 23, 2003
Filed:
Jun. 27, 2000
Christopher John Abel, Whitehall, PA (US);
Angelo Rocco Mastrocola, West Lawn, PA (US);
Douglas Edward Sherry, Mertztown, PA (US);
William Burdett Wilson, Macungie, PA (US);
Lucent Technologies Inc., Murray Hill, NJ (US);
Abstract
A loss-of-clock (LOC) detector circuit detects a clock failure substantially within a specified number of clock periods and generates a loss-of-clock signal. The LOC detector includes a frequency-to-current converter which generates a charging current substantially proportional to a frequency of an input clock. A capacitor accepts the charging current and provides a terminal voltage that changes in response to the charging current. An edge detector receives the input clock signal as an input and produces an output pulse on an edge of the input clock signal. A switch is coupled to the capacitor such that the capacitor is discharged to a reference potential when the switch is closed. The switch is controlled by the edge detector to close when the edge detector output pulse is asserted. A comparator generates a loss-of-clock signal when the voltage on the capacitor passes a trip voltage of the comparator.