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US 6,140,853 AGranted
Digital phase detector and charge pump system reset and balanced current source matching
AssigneeCypress Semiconductor Corporation
InventorChung-Wen Dennis Lo
Life of this patent
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Abstract
A digital phase detector and charge pump circuit system reset circuit and method resets a digital phase detector according to the charge outputs between the charge pump circuits and a following loop filter. The sensing circuitry emulates portions of the circuitry of the digital phase detector and charge pump circuit system and minimizes deadband time. Current mirror portions of the charge pump circuit alternate between p-channel and n-channel devices to regularize output voltage levels produced by the charge pump circuit system.
Claims17
A circuit comprising:
- a charge pump circuit configured to present a first output and a second output in response to a first phase comparator output signal and a second phase comparator output signal;
- a phase comparator circuit configured to provide said first and second phase comparator output signals in response to (i) a first input phase signal, (ii) a second input phase signal, and (iii) a reset signal;
- and
- a logic circuit configured to present said reset signal in response to said first and second outputs, and said first and second phase comparator output signals.
1 more element
Dependencies are inferred from the claim text.