US Patent 7595699 Look loop circuit and method having improved lock time

A lock loop circuit (230) includes a floating ground loop filter circuit (302) and a precharge circuit (304). The floating ground loop filter circuit includes at least one capacitive element (326, 328). The floating ground loop filter circuit provides a steering signal (334) for a controllable oscillator circuit (306) in response to a precharge signal (347). The precharge circuit provides the precharge signal in response to lock loop enable information (226). The precharge circuit controls the floating ground loop filter to bypass the at least one capacitive element for a period of time (606) in response to the lock loop enable information.