To enlarge an operation frequency range while preventing area expansion caused by the use of an inductor, yield reduction caused by manufacture variation, and the like.
There are provided a voltage controlled oscillator 106 which oscillates at a frequency controlled by a control voltage and outputs an oscillation signal; a prescaler 107 capable of controlling a free-running frequency to frequency-divide the oscillation signal and output a first frequency division signal; a programmable divider 102 which frequency-divides the first frequency division signal and outputs a second frequency division signal; and a phase comparator 108 which compares a phase of the second frequency division signal with the phase of a reference clock signal and outputs a signal corresponding to a phase difference. There are further provided a control voltage generating section for generating the control voltage in accordance with the phase difference; a frequency comparator 103 which compares the frequency of the second frequency division signal with that of the reference clock signal and outputs a signal corresponding to the frequency difference; and a control section 109 which controls the free-running frequency so as to minimize the frequency difference in accordance with the signal corresponding to the frequency difference.
OTAKA SHOJI
WATANABE OSAMU
HOSHINO HIROAKI
Satoshi Kono
Makoto Nakamura
Kurata Masatoshi
Takashi Mine
Yoshihiro Fukuhara
Sadao Muramatsu
Ryo Hashimoto
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