Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Rectangular or pulse waveform width control
Reexamination Certificate
2006-05-01
2008-09-02
Richards, N. Drew (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Rectangular or pulse waveform width control
C327S035000, C327S036000, C714S744000
Reexamination Certificate
active
07420400
ABSTRACT:
The disclosed methodology and apparatus measures the duty cycle of a reference clock signal that a clock circuit supplies to a duty cycle measurement (DCM) circuit located “on-chip”, namely on an integrated circuit (IC) in which the DCM circuit is incorporated. In one embodiment, the DCM circuit includes a capacitor driven by a charge pump. The reference clock signal drives the charge pump. The clock circuit varies the duty cycle of the reference clock signal among a number of known duty cycle values. The DCM circuit stores resultant capacitor voltage values corresponding to each of the known duty cycle values in a data store. The DCM circuit applies a test clock signal having an unknown duty cycle to the capacitor via the charge pump, thus charging the capacitor to a new voltage value that corresponds to the duty cycle of the test clock signal. Control software accesses the data store to determine the duty cycle to which the test clock signal corresponds.
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Boerstler David William
Hailu Eskinder
Qi Jieming
International Business Machines - Corporation
Kahler Mark P
Luu An T.
Richards N. Drew
Talpis Matthew B
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