| 摘要 |
<P>PROBLEM TO BE SOLVED: To solve the problem that the power consumption of a conventional voltage-controlled oscillator is difficult to be reduced because an initial voltage is continuously applied to the voltage-controlled oscillator over a prescribed required time. <P>SOLUTION: An initial operation control circuit of a PLL circuit includes: an initial voltage generating circuit for generating an initial voltage nearly corresponding to a frequency as a control voltage to be applied to the voltage-controlled oscillator in an initial state of the PLL circuit, the frequency being a frequency of an oscillated signal; a switch circuit for opening/closing a path through which the initial voltage generating circuit applies the initial voltage to the voltage-controlled oscillator; and a timer circuit for measuring a second period so as to bring the switch circuit to an opening state at the end of the second period whose start time is the same as the start time of a first period, the second period being shorter than the first period and being a period until the oscillation of the signal with the frequency by the voltage-controlled oscillator is stable after the initial voltage is applied to the voltage-controlled oscillator resulting from the closing state of the switch circuit. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
