Circuit and method for phase locked loop charge pump biasing

US6989718B2 · kind B2 · utility

Assignee

• Infineon Technologies AG · DE

Inventors

• Harald Pretl
• Michael Wilhelm · Lambach, DE

Key dates

• Filing date: Jan 20, 2004
• Grant date: Jan 24, 2006
• Expiry date: Mar 7, 2024

Classification

• Technology area (CPC H): Electricity
• CPC primary: H03L7/0898
• WIPO field: Basic communication processes
• WIPO sector: Electrical engineering

Abstract

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.