| 摘要 |
PROBLEM TO BE SOLVED: To provide a clock oscillation circuit that automatically trims an oscillated frequency based on a clock applied externally with respect to a clock oscillation circuit which is dependent on dispersion of components. SOLUTION: This clock oscillation circuit is provided with an oscillation section 1, that provides an output of a clock whose oscillated frequency changes with a parameter, a frequency measurement circuit that measures the oscillated frequency of an oscillation section on the basis of a calibration clock, and a trimming control circuit 7 that trims the parameter by using a binary search to adjust the trimmed value, in response to the measured oscillation frequency. The frequency measurement circuit is provided with a frequency divider 9 tat frequency-divides the calibration clock, a counter 4 that counts clocks outputted from the oscillation section and is reset by an output of the frequency divider, a register 5 that latches a prescribed target count value, and a comparator 6 that compares the maximum count of the counter with the target count value. |
