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US 7,078,946 B2Granted
Analog PLL with switched capacitor resampling filter
AssigneeZarlink Semiconductor Inc.
InventorsRobertus Laurentius van der Valk, Gerrit Dijkstra, Philip Ching
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Abstract
A resampler filter for use in an analog phase-locked loop has a charge pump and one or more switched capacitors switched by signals derived from a voltage controlled oscillator in the phase locked loop.
Claims16
A phase locked loop comprising:
- a phase detector having an output;
- a voltage controlled oscillator having an input;
- a feedback loop connecting an output of said controlled oscillator to an input of said phase detector;
- and
- a resampling filter connecting the output of said phase detector to the input of said controlled oscillator;
- and
- said resampling filter comprising:
- a charge pump;
- a plurality of switched capacitors arranged in a parallel arrangement between ground and line;
- a first switch in said common line for switchably connecting said charge pump to a first of said capacitors;
- and
- further switches in said common line between adjacent pairs of said capacitors;
- and
- wherein said first switch and said further switches are controlled by signals derived from the voltage controlled oscillator so as to successively distribute charge over said switched capacitors.
11 more elements
Dependencies are inferred from the claim text.