Patent ID: 8587355

Claim:
A coarse lock detector configured to count a number of edges of one or more of a plurality of multiphase clocks in one cycle of an input reference clock, to output a lock signal in a first state if the number of edges is within a lock range, or to output the lock signal in a second state if the number of edges is outside the lock range, wherein the lock range is changeable between a first lock range and a second lock range, and the coarse lock detector initially sets the lock range to the first lock range, changes the state of the lock signal to the first state once the number of edges is within the first lock range, changes the lock range to the second lock range once the number of edges in N cycles of the input reference clock is within the first lock range, outputs the lock signal in the first state while the number of edges is within the second lock range, and changes the state of the lock signal to the second state and the lock range to the first lock range if the number of edges is outside the second lock range.