Patent ID: 8432203

Claim:
Phase locked loop circuitry comprising: a voltage controlled oscillator, for adjusting phase or frequency characteristics of an output signal, having a first input terminal and an output terminal on which the output signal is provided; a phase and frequency detector which generates analog VCO input signals indicative of a phase difference or a frequency difference between the VCO output signal and a reference signal; conversion circuitry coupled to translate the analog VCO input signals from an analog form into digital versions to adjust the VCO output signal; signal driving circuitry, comprising a current source an output of which is a control signal generated by input of the digital version of the analog VCO input signals to the signal driving circuitry; first input circuitry providing a first adjustment signal to the first input terminal of the VCO; and second input circuitry providing a second adjustment signal to the first input terminal of the VCO in response to the control signal, wherein: the first adjustment signal is based on input of the VCO input signals in the analog form to a circuit element in the first input circuitry to control the first adjustment signal; and the control signal, to which the second input circuitry is responsive to provide the second adjustment signal, is determined with the digital versions of the VCO input signals.