Patent ID: 7693247
Filing Date: 2010-04-06
Classification: H03L

Abstract:
1. A phase locked loop, comprising: a controlled oscillator for outputting a periodic output signal as a result of a control signal; a feedback unit for providing at least two periodic feedback signals having a constant phase shift to each other, wherein each feedback signal depends on the output signal, and wherein the at least two periodic signals comprise an in-phase feedback signal which has no phase shift with respect to the output signal and a quadrature-phase feedback signal which has a 90° phase shift with respect to the output signal; a frequency/phase detector for providing difference signals, each difference signal depending on a periodic input signal and at least one of the feedback signals; and a control circuit for providing the control signal to the controlled oscillator depending on the difference signals, the control circuit comprising a charge pump that provides current pulses in response to the difference signals and adds the current pulses to provide a current output; wherein at least one of the difference signals provided by the frequency/phase detector is a phase difference signal depending on the result of a comparison between one of the feedback signals and the input signal; and at least one other of the difference signals provided by the frequency/phase detector is a frequency difference signal depending on the result of a comparison between one of the feedback signals and the input signal.