Patent ID: 7218157

Claim:
A phase looked loop comprising a phase detector for determining a phase difference between a reference signal and relative phase shifted signals to generate frequency control signals the phase detector comprising: means for obtaining a one of said frequency control signals by binary multiplication of the reference signal and one of the relative phase signals; means for obtaining a second one of said frequency control signals by binary multiplication of the relative phase shifted signals; a frequency detector coupled to receive the reference signal and the relative phase shifted signals for supplying an up frequency detector signal and a down frequency detector signal to a charge pump that is coupled to a loop filter, wherein the frequency detector comprises a third flip-flop and a fourth flip-flop driven by the reference signal and having at their inputs the relative phase signals, outputs of the third and fourth flip-flops being coupled to input terminals of a fifth flip-flop the frequency detector generating the up frequency detector signal obtained by binary multiplication between a signal generated by the fifth flip-flop at its output and the signal obtained at the bar-output of the fourth flip-flop, and further generating the down frequency detector signal obtained by binary multiplication of the signal obtained at a bar-output of the fourth flip-flop and the signal obtained at a bar-output of the fifth flip-flop signal obtained at the bar-output of the fourth flip-flop.