| 摘要 |
Phase locked loops systems and control apparatus therefor are presented, in which a first charge pump bias current is generated according to a sensed VCO tuning voltage and a second generally constant bias current is provided. The provision of the first and second bias currents allows compensation for non-linear VCO tuning sensitivity. Methods are also presented for biasing a charge pump, including selectively providing a first current to the charge pump using a first current source, controlling the first current according to a VCO tuning voltage of the phase locked loop system, and providing a substantially constant second current to the charge pump.
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