Patent ID: 7212049

Claim:
A digital-control phase-composing circuit system comprising: a phase-composing circuit which is supplied with two input clock signals having a phase difference therebetween and a control signal, and which composes an output clock signal having a phase difference between the phases of the two input clock signals, based on weighting through the control signal; a binary comparison circuit which compares the phase of the output clock signal to the phase of a reference clock signal; a first up/down counter which increments or decrements a first count value based on results of the comparison made by the binary phase comparison circuit, outputs the most significant bit of the first count value, and outputs a clock pulse when a carry or a borrow occurs in the first count value; and a second up/down counter which uses the clock pulse as an operating clock, increments or decrements a second count value based on the most significant bit of the first count value, and outputs the second count value as the control signal.