Phase lock loop with coarse control loop having frequency lock detector and device including same

Abstract

A phase lock loop (PLL) for controlling a sampling clock or other clock, and a data sampling circuit, transceiver, or other device including such a PLL. The PLL includes a multi-range VCO, at least one fine control loop for controlling the VCO, and a coarse control loop for controlling the VCO by changing its frequency-voltage characteristic. The coarse control loop includes a frequency lock detector and voltage range monitoring logic. Typically, the frequency lock detector locks operation of the coarse control loop when the difference between the VCO output clock frequency and a reference frequency decreases to within a predetermined threshold, and the unlocked coarse control loop employs the voltage range monitoring logic to change the VCO frequency-voltage characteristic when the VCO's fine control voltage leaves a predetermined range. Other aspects are a transceiver (including at least two receiver interfaces and a transmitter interface) implementing a clocking scheme employing no more than three PLLs for clock generation, and a transceiver having a multi-layered receiver interface including digital circuitry and a single clock-generating PLL (an analog PLL for generating a multiphase clock to be shared by all layers of the receiver interface). Each receiver interface layer performs blind oversampling on a different received signal using the multiphase clock and the digital circuitry includes multilayered digital phase lock loop circuitry which receives the oversampled data.