Phase-locked loop (PLL) for high-frequency (HF) signals

摘要

In a PLL circuit, the precharging function necessary for setting a required initial state of a VCO is achieved by an additional precharge pump inserted in parallel with the charge pump, or alternatively by multiplexers and inverters implemented directly with the charge pump. The precharging function being controlled in both cases by two control signals. PLL circuits according to the invention are applied, in particular, in integrated circuits of mobile transceivers, for example for GSM, PCN and PCS.