Patent ID: 7016451

Claim:
A phase detector for providing a control signal according to the phase relationship between first and second clock signals, the phase detector comprising: first phase detector circuit having first and second transition detectors and a flip-flop, each signal transition detector having an input terminal to which a respective one of the first and second clock signals are provided and configured to produce a trigger pulse at an output in response to the respective clock signal changing logic states, the flip-flop having first and second inputs coupled to the output of a respective one of the signal transition detectors and further having an output terminal for the first phase detector at which a first phase dependent output signal is provided; a second phase detector circuit having first and second input terminals to which the first and second clock signals are provided, respectively, and further having an output terminal at which a second phase dependent output signal is provided; and a current source having first and second input terminals coupled to the output terminal of the first and second phase detector circuits and further having an output terminal, the current source providing an output current having a polarity according to the relative duty cycles of the first and second phase dependent output signals, and no output current responsive to the duty cycles of the first and second phase dependent output signals being substantially the same.