| 摘要 |
PROBLEM TO BE SOLVED: To provide a voltage-controlled oscillator that satisfies all of high-speed starting properties, low-phase noise properties, and low power consumption characteristics. SOLUTION: A bias part is composed by having a current source, a first transistor connected to the current source in a series form, a second transistor which supplies a bias current to a body part generating an oscillation signal at a desired frequency corresponding to a control voltage while being current-mirror connected to the first transistor, a switch circuit connected between control terminals of the first/second transistors so as to function as a resistance element, and a capacitative element connected to the control terminal of the second transistor. The current source executes the current supply operation to the first transistor during a starting state of the voltage-controlled oscillator and stops the current supply operation to the first transistor during a normal state of the voltage-controlled oscillator. The switch circuit is turned on during the starting state of the voltage-controlled oscillator and turned off during the normal state of the voltage-controlled oscillator. COPYRIGHT: (C)2007,JPO&INPIT
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