Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Synchronizing
Reexamination Certificate
2011-05-17
2011-05-17
Donovan, Lincoln (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Synchronizing
C327S146000, C327S155000, C327S158000, C375S375000
Reexamination Certificate
active
07944261
ABSTRACT:
Method and apparatus for detecting clock loss in clock circuit. An example of the invention relates to detecting loss of a feedback clock signal input to a digital clock manager, where the feedback clock signal is derived from the reference clock signal. A clock divider is provided to produce a divided feedback clock signal from the feedback clock signal. A first pair of flip-flops is configured to store samples of the divided feedback clock signal on consecutive edges of the reference clock signal. A second pair of flip-flops is configured to store samples of the divided feedback clock signal on consecutive edges of an inversion of the reference clock signal. Detection logic is configured to detect whether each of the first pair of flip-flops and each of the second pair of flip-flops store the same value.
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Lynch Patrick T.
Wadhwa Amit
Brush Robert M.
Cole Brandon S
Donovan Lincoln
Maunu LeRoy D.
Xilinx , Inc.
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