| CPC H03L 5/00 (2013.01) [H03L 7/089 (2013.01); H03L 7/0895 (2013.01); H03L 7/0896 (2013.01); H03L 7/093 (2013.01)] |
| AS A RESULT OF REEXAMINATION, IT HAS BEEN DETERMINED THAT: |
| Claims 1 and 13 are determined to be patentable as amended. |
| New claims 21-24 are added and determined to be patentable. |
| Claims 2-12 and 14-20 were not reexamined. |
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1. A charge pump, being disposed in a phase locking system, the charge pump comprising:
a sourcing element, arranged to selectively source a first current into an output terminal of the charge pump according to a first control signal;
a draining element, arranged to selectively drain a second current from the output terminal according to a second control signal; and
an offset element, arranged to selectively conduct an offset current via the output terminal according to a third control signal, wherein [ : ]
one of the sourcing element and the draining element is disabled when the phase locking system is in a phase-locked state [ ;
the third control signal comprises a signal having a first interval and a second interval; and
the offset element conducts the offset current during the first interval and is disabled during the second interval] .
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13. A charge pump method utilized in a phase locking system, comprising:
selectively performing a sourcing operation to source a first current into an output terminal of a charge pump in the phase locking system according to a first control signal;
selectively performing a draining operation to drain a second current from the output terminal according to a second control signal; and
selectively performing an offset operation to conduct an offset current via the output terminal according to a third control signal, wherein [ :]
one of the sourcing and the draining operations is disabled when the phase locking system is in a phase-locked state [ ;
the third control signal comprises a signal having a first interval and a second interval; and
the offset operation conducts the offset current during the first interval and is disabled during the second interval.]
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[ 21. The charge pump of claim 1, wherein:
the first interval comprises a sampling interval;
the second interval comprises a holding interval;
during the sampling interval the first current cancels the offset current; and
during the holding interval the offset element is disabled.]
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[ 22. The charge pump of claim 1, wherein:
the sourcing element comprises at least two PMOS transistors; and
the draining element comprises at least two NMOS transistors.]
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[ 23. The charge pump of claim 1, wherein the offset current is smaller than at least one of the first current or the second current.]
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[ 24. The charge pump of claim 1, further comprising a loop filter coupled between the output terminal and a voltage-controlled node of the phase locking system,
wherein:
the loop filter comprises a capacitor, a resistor, and a switching element configured to selectively connect the output terminal to the voltage-controlled node according to the third control signal;
during the first interval, the switching element electrically isolates the output terminal from the voltage-controlled node; and
during the second interval, the switching element couples the output terminal to the voltage-controlled node.]
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