| 摘要 |
A delay circuit including a plurality of interpolators connected in cascade. Each of the interpolators receives a reference clock signal and a clock signal output from the preceding interpolator. One of the interpolators generates a clock signal whose transition edge is between the transition edge of the reference clock signal and the transition edge of the clock signal. The subsequent interpolators operate as delay stages, thereby generating a delayed clock signal delaying from the reference clock signal by a predetermined time. It is possible to make smaller the minimum unit of a delay adjustment to the delayed clock signal by using the interpolators. A semiconductor integrated circuit including the delay circuit supplies ratio information to the phase adjustment circuits based on the result of comparing the phase of the reference clock signal with the phase of the delayed clock signal from a phase comparator and makes the phase of the delayed clock signal coincide with the phase of the reference clock signal. As a result, the phase adjustment can be made with reliability even when a reference clock signal of higher frequency is supplied.
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