Patent ID: 7633347
Filing Date: 2009-12-15
Classification: H03L

Abstract:
1. A phase-locked loop circuit with a loop path, said loop path comprising: a charge pump with a charge resistor section for generating a charge pump current; a loop filter with a filter resistor section and a filter capacitor section coupled to said charge pump for generating an oscillator control voltage based on said charge pump current; and a voltage controlled oscillator with an oscillator resistor section and an oscillator capacitor section coupled to said loop filter for generating an output clock under control of said oscillator control voltage, wherein a resistance variation of said filter resistor section is proportional to a resistance variation of said charge resistor section and a resistance variation of said oscillator resistor section, and a capacitance variation of said filter capacitor section is proportional to a capacitance variation of said oscillator capacitor section to maintain a damping factor of said phase-locked loop circuit substantially constant.