Method for controlling phase-locked loop, gain control device, and phase-locked loop system

摘要

A multi-Gigahertz, low jitter phase locked loop (PLL) with adjustable gain is disclosed. In one embodiment, properties of a fSUBVCO /SUBsignal of a PLL can be acquired. Properties can include the occurrences of different types of jitter on the fSUBVCO /SUBsignal and the lock status of the PLL. A gain control module can control at least a portion of the PLL based on an analysis of the acquired properties. For example, when the loop is locked or when there is loop filter leakage, the gain of a charge pump in the PLL can be reduced. When a charge pump mismatch is detected based on the acquired properties, additional control signals can be provided to the charge pump to correct the mismatch.