Patent ID: 7616068

Claim:
An integrated circuit radio transceiver, comprising: a baseband processor for generating outgoing digital signals and for receiving and processing ingoing digital signals; front-end circuitry for producing outgoing RF based upon the outgoing digital signals and for producing the ingoing digital signals based upon received ingoing RF; and a frequency synthesizer of the front-end circuitry that generates a local oscillation for front-end circuitry operations, comprising: a signal level stage comprising first and second capacitive blocks; a selectable first switch operable to create a shorting signal path, the selectable first switch operably disposed across the first capacitive block and circuit common; a selectable second switch operably disposed between an input node of the selectable first switch and an input of the second capacitive block; wherein at least one of the first and second capacitive blocks comprises a plurality of parallel coupled capacitors and further wherein at least one of the plurality of parallel coupled capacitors is selectable; and logic operable to regulate charge sharing between the first and second capacitive blocks to control a voltage controlled oscillator (VCO) input voltage by generating switch control signals to perform specified switching to open the selectable second switch while closing the selectable first switch to short the first parallel coupled capacitive block and to open the selectable first switch while closing the second selectable switch to allow the first and second parallel coupled capacitive blocks to share charge.