Digitally controlled oscillator circuit

PROBLEM TO BE SOLVED: To provide a technology for generating a stabilized-accuracy clock regardless of a length of a cycle.SOLUTION: A rough cycle generation part (71) acquires a cycle setting value represented by a magnification with respect to a cycle of a reference clock prepared beforehand and generates rough cycle timing for each cycle represented by an integral part of the magnification by counting the reference clock while defining the integral part as a count value. A fraction conversion part (72) generates a fraction by converting a decimal part of the magnification into the number of stages through which a pulse signal passes a delay element. Output processing parts (73 and 8) select timing in which output of a ring oscillator and a counter circuit becomes a value corresponding to the fraction generated by the conversion part, as output timing after the lapse of just a time corresponding to the fraction from the rough cycle timing and use the output timing to generate an output signal to be oscillated in the cycle indicated by the cycle setting value.SELECTED DRAWING: Figure 16