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US 2003/0189463 A1Published application
Current saving technique for charge pump based phase locked loops
OwnerBrett C. Walkerinventor
Life of this patent
Estimating the term…
Abstract
A charge pump circuit includes a charge pump current source configured for differential switching of an output current and a charge pump enable switch configured to turn on the charge pump current source prior to the differential switching of the output current and to turn off the charge pump current source after the differential switching of the output current, thereby saving a significant amount of current consumption by the charge pump circuit.
Claims36
A charge pump circuit comprising:
- a charge pump current source configured for differential switching of an output current;
- and
- a charge pump enable switch configured to turn on said charge pump current source prior to said differential switching of said output current.
A charge pump circuit comprising:
- a current source and a current sink, wherein said current source and said current sink are configured to provide an output current;
- an output node configured to connect said output current to a circuit external of the charge pump circuit;
- a dump node configured to absorb current from said current source and to supply current to said current sink;
- a pump up switch configured to connect said current source to said output node and to connect said current source to said dump node;
- a pump down switch configured to connect said current sink to said output node and to connect said current sink to said dump node wherein said pump up switch and said pump down switch are configured for differential switching of said output current;
- and
- a charge pump enable switch configured to turn on said current source and said current sink prior to said differential switching of said output current.
4 more elements
A phase locked loop comprising:
- an oscillator oscillating at a frequency;
- a frequency divider driven by said oscillator and providing a local signal;
- a PFD, wherein said PFD compares an input signal to said local signal to provide a pump up signal and a pump down signal;
- a charge pump, wherein said charge pump comprises:
- a charge pump current source configured for differential switching of an output current, in response to said pump up signal and said pump down signal, and
- a charge pump enable switch configured to turn on said charge pump current source prior to said differential switching of said output current;
- and
- a loop filter, wherein said loop filter uses said output current to control said frequency of said oscillator, whereby said local signal tracks said input signal.
5 more elements
A charge pump circuit comprising:
- a current source and a current sink, wherein said current source and said current sink are configured to provide an output current;
- an output node configured to connect said output current to a loop filter of a phase locked loop;
- a dump node configured to absorb current from said current source and to supply current to said current sink;
- a pump up switch configured to connect said current source to said output node and to connect said current source to said dump node;
- a pump down switch configured to connect said current sink to said output node and to connect said current sink to said dump node wherein said pump up switch and said pump down switch are configured for differential switching of said output current;
- and
- a charge pump enable switch configured to turn on said current source and said current sink for a warm up period prior to said differential switching of said output current, wherein said warm up period comprises an amount of time adequate for said output current to settle to a required accuracy prior to said differential switching of said output current, wherein said warm up period is between approximately 100 ns and approximately 300 ns, wherein said charge pump enable switch is configured to turn off said current source and said current sink after said differential switching of said output current, wherein said charge pump enable switch is configured to switch according to a charge pump enable signal, and wherein said charge pump enable signal is provided from a frequency divider and from a PFD in said phase locked loop.
4 more elements
A method for reducing current consumption in a charge pump circuit, comprising steps of:
- providing a charge pump enable signal;
- using said charge pump enable signal to turn on a charge pump current source prior to a charge pump event;
- providing an output current using said charge pump current source during said charge pump event;
- and
- turning off said charge pump current source, using said charge pump enable signal, after said charge pump event.
2 more elements
Dependencies are inferred from the claim text.