Abstract: A method of startup for a phase-locked loop (PLL) can include, at initiation of the PLL, providing a reference voltage from a startup voltage source to an input of a voltage controlled oscillator (VCO) in the PLL, wherein the reference voltage is set to a predetermined minimum voltage. The reference voltage can be stepwise increased from the predetermined minimum voltage. A frequency of a reference signal input to the PLL can be compared with a frequency of a feedback signal originating from an output of the VCO of the PLL to determine a frequency differential as the reference voltage increases. A determination can be made as to whether a convergence criterion is met according to the frequency differential. While the convergence criterion is not met, the reference voltage can be increased. When the convergence criterion is met, the reference voltage provided by the startup voltage source can be replaced with a voltage generated by an operational voltage source.

Abstract: A charge pump circuit has a charge pump section and a replica charge pump section. The replica charge pump section produces a replica voltage at which the UP current will match the DOWN current. A comparator compares the replica voltage to the output voltage, and adjusts the bias to the charge pump section and replica charge pump section so that the voltage level produced by the replica charge pump section matches the output voltage.