VOLTAGE-CONTROLLED OSCILLATOR

PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator which reduces phase noise while keeping its operation stable. SOLUTION: A current mirror circuit part 3 is connected to power supply potential wiring VCC, and a current control part 4 for regulating a size of a current that is made flow to the current mirror circuit part 3 is provided between the current mirror circuit part 3 and ground potential wiring GND. Besides, a negative resistor part 5, an LC circuit part 6 and a negative resistor part 7 are provided in this order parallel with the current control part 4 between the current circuit part 3 and the ground potential wiring GND. The LC circuit part 6 is equipped with an inductor L, variable capacitors C1 and C2, and capacitors C3-C8. In the current control part 4, the same control signal is inputted respectively to an N-channel transistor N2 in the current control part 4 and switches S1 and S4 in a resonant part 6, to an N-channel transistor N3 and switches S2 and S5, and to an N-channel transistor N4 and switches S3 and S6 so as to open/close the transistors and the switches while being interlocked. COPYRIGHT: (C)2004,JPO&NCIPI