Patent ID: 7508277

Claim:
A phase-locked loop (PLL) capable of compensating a voltage controlled oscillator gain, said phase-locked loop comprising: a phase detector comprising: a mixer for receiving a reference signal and a first feedback signal corresponding to an output signal outputted from a voltage controlled oscillator (VCO), and outputting a phase difference signal in response to a phase difference between the first feedback signal and the reference signal, the mixer being biased by a bias current; and a bias circuit for outputting the bias current in response to receiving a gain controlled signal and thereby affecting a phase detector gain of the phase detector; a loop filter for filtering the phase difference signal to output a frequency controlled signal; a gain controller having an input coupled to receive a second feedback signal corresponding to the phase difference signal, and generating the gain controlled signal in accordance with the second feedback signal; and the VCO having an input coupled to receive the frequency controlled signal, the VCO also outputting the output signal in response to the frequency controlled signal; wherein the phase detector gain is adjusted in accordance with the second feedback signal.