Abstract:
Described is an integrated circuit (IC) with a phase locked loop with capability of fast locking. The IC comprises: a node to provide a reference clock; a digitally controlled oscillator (DCO) to generate an output clock; a divider coupled to the DCO, the divider to divide the output clock and to generate a feedback clock; and control logic operable to reset the DCO and the divider, and operable to release reset in synchronization with the reference clock. An apparatus for zeroing phase error is provided which comprises a first node to provide a reference clock; a second node to provide a feedback clock; a time-to-digital converter, coupled to the first and second nodes, to measure phase error between the reference and feedback clocks; a digital loop filter; and a control unit to adjust the measured phase error, and to provide the adjusted phase error to the digital loop filter.
Abstract:
Described is an apparatus which comprises: a time-to-digital converter (TDC) to receive a reference clock and a feedback clock, wherein the TDC is to generate a digital output code representing a time difference between the reference clock and the feedback clock; a circuitry to apply a digital code to an output of the TDC; and a node to receive the digital output code from the TDC and the digital code from the circuitry, wherein the circuitry is to monitor the digital output code and to control the TDC according to at least the monitored digital output code.