| 摘要 |
PROBLEM TO BE SOLVED: To provide a ring oscillator circuit of which the oscillation period can be finely adjusted with a variable width narrower than a conventional circuit. SOLUTION: In a ring oscillator body, one of a plurality of logic gates is a switching circuit having two or more inputs, and an output signal of the switching circuit rises in accordance with a first signal entered through a first path and falls in accordance with a second signal which is entered through a second path and has the same polarity as the first signal and has a propagation delay time different from that of the first signal by a time corresponding to a delay time of a two-stage inverter. A duty correction circuit includes; a first detection circuit for detecting the rise of an output signal of a first logic gate being one of the plurality of logic gates; a second detection circuit for detecting the rise of an output signal having the polarity opposite to that of the output signal of the first logic gate, of an inverter being a second logic gate in a stage next to the first logic gate; a synthesizing circuit for synthesizing output signals of the first and second detection circuits; and a frequency divider for dividing a frequency of an output signal of the synthesizing circuit and outputting division results as a clock. COPYRIGHT: (C)2006,JPO&NCIPI
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