Patent ID: 7321267
Filing Date: 2008-01-22
Classification: H03L

Abstract:
1. A method for operating a phase locked loop, which phase locked loop comprises a voltage controlled oscillator and an active loop filter, wherein said voltage controlled oscillator generates an alternating-current output signal having a frequency which depends on an applied control voltage, and wherein said active loop filter provides a control voltage to said voltage controlled oscillator, said control voltage reflecting determined phase differences between a potentially frequency divided output signal of said voltage controlled oscillator and a reference signal, said method comprising: detecting frequency deviations between said potentially frequency divided output signal of said voltage controlled oscillator and said reference signal, wherein a resolution employed for detecting said frequency deviations is lower than a resolution employed for determining said phase differences; and adding a direct-current voltage shift at an output of said active loop filter to said control voltage provided by said active loop filter, in case a frequency deviation is detected for reducing dielectric absorption of at least one capacitor of said active loop filter, said phase locked loop, including said at least one capacitor, being integrated in an integrated circuit.