Patent ID: 6483390
Filing Date: 2002-11-19
Classification: H03J,H03L

Abstract:
A wireless communication frequency synthesizer for generating multiple band high-frequency signals, comprising:a phase locked loop (PLL) having an output frequency dependent upon a voltage controlled oscillator (VCO); a VCO within the PLL, the VCO having an output frequency dependent upon LC tank resonant structure and being selectably operable at a plurality of different frequencies within a plurality different frequency bands; inductance circuitry coupled to the VCO as part of the LC tank resonant structure, the inductance circuitry configured to provide a selectable inductance amount that determines the frequency band of operation; capacitance circuitry integrated within the VCO as part of the LC tank resonant structure, the capacitance circuitry configured to provide a controllable capacitance amount that determines the frequency of operation within the selected frequency band, the capacitance circuitry comprising: a plurality of discretely variable capacitor circuits that together provide at least part of the capacitance amount, each discretely variable capacitor circuit having at least one control node configured to receive a digital control signal that determines whether an individual capacitance amount associated with the discretely variable capacitor circuit is contributed to the capacitance amount; a plurality of different digital signals coupled to the VCO to provide the digital control signals to the discretely variable capacitor circuits; a plurality of continuously variable capacitor circuits that together provide at least part of the capacitance amount, each continuously variable capacitor circuit having at least one control node configured to receive an analog control signal that determines at least in part an amount of capacitance contributed by that continuously variable capacitor circuit to the capacitance amount; and a plurality of different analog signals coupled to the VCO to provide the analog control signals to the plurality of continuously variable capacitor circuits, the different analog signals being adjusted based upon a phase difference between a first signal that is related to the output frequency and a second signal that is related to a reference frequency.