Constant-Ratio-Coupled Multi-Grain Digital Synchronizer With Flexible Input-Output Delay Selection for Versatility in Low-Power Applications

A Time-Constant Calibrated Phase-Locked Loop With a Fast-Locked Time

“…In order to adjust the equivalent capacitance in the loop filter, a variable capacitance multiplier (VCM) is also developed. To save the power, the clock generator will be stopped and be re-started once the demand is active [2]. By using the proposed time-constant calibration circuit and the VCM, a fast acquisition time for a PLL is achieved.…”