| 摘要 |
PROBLEM TO BE SOLVED: To provide an LC resonance circuit, enabling the rate of change of the capacitance of a voltage-controlled variable capacitance element to be set, as desired according to the design, having high-controllability and high- performance voltage-controlled oscillator(VCO) utilizing this circuit. SOLUTION: When a control voltage Vin is inputted, voltage-lowering means NMOS 111-113 for lowering the voltage Vin one after another. The dropped voltages are applied to control electrodes of parallel-connected controlled variable capacitance elements MOS varactors 211-213, to determine the capacitance values of the varactors. An LC resonance circuit, composed of the varactors 211-213 and a coil 22 resonates at a prescribed frequency, switching means NMOS 23, 24 which turn on/off to oscillate at an oscillation frequency according to the control voltage Vin, and this oscillation signal is outputted from terminals 3, 4. |
