Patent ID: 7800458
Filing Date: 2010-09-21
Classification: H03B,H03L

Abstract:
1. A wide-band voltage controlled oscillator comprising: a cross-connected oscillator configured to provide an oscillating signal; an inductor unit configured to provide inductance for determining a resonance frequency of the oscillating signal; a varactor bank comprising a plurality of switchable variable-capacitance elements which are connected to the inductor unit in parallel and have predetermined varactor capacitances, wherein one of the plurality of switchable variable-capacitance elements is selected by a first switching signal so that the varactor bank has a variable capacitance varying with a tuning voltage; a subsection capacitor bank comprising a plurality of switchable capacitor elements connected to the inductor unit in parallel, having predetermined capacitances for fractionized frequency sections, and selectively switched on by a second switching signal so that the subsection capacitor bank has a variable capacitance for the fractionized frequency sections; and a binary-weighted capacitor bank comprising a plurality of binary-weighted capacitor banks connected to the inductor unit in parallel and a bank selector configured to select one of the plurality of binary-weighted capacitor banks according to a bank selection signal, wherein each of the binary-weighted capacitor banks comprises a plurality of switchable capacitor elements which are connected in parallel to one another and selectively switched on by a third switching signal so that the binary-weighted capacitor bank has a variable binary-weighted capacitance, wherein the ratio of the variable capacitance of the varactor bank to the total capacitance of the subsection capacitor bank and the binary-weighted capacitor bank is kept constant for a plurality of predetermined frequency sections comprising a first frequency section, a second frequency section, a third frequency section and a fourth frequency section, wherein the total capacitance of the subsection bank and the binary-weighted capacitor bank is further set to vary in a nearly exponential way according to a digital control signal.