| 摘要 |
PROBLEM TO BE SOLVED: To provide a clock data recovery circuit and a semiconductor device, capable of reproducing a clock signal from an input data signal without producing accuracy deterioration even at high-speed communication operation.SOLUTION: When reproducing a reference clock signal that is phase synchronized with a transition part (reference transition part) of data that appears in an input data signal on the basis of each reference transition period, the clock data recovery circuit first detects a transition part having a shifted data value from the input data signal, to generate a transition detection signal. Next, the clock data recovery circuit extracts two mutually consecutive transition parts from the transition detection signal on the basis of each of the reference transition period, and generates a first clock signal synchronized with the first transition part in the two transition parts and a second clock signal synchronized with the second transition part. Based on a data value immediately before the latter transition part of the first and second transition parts, the clock data recovery circuit selects one of the first and second clock signals, to output it as a reference clock signal. |
