Semiconductor device

摘要

A frequency tracking loop receives a result from a phase detector that detects an advance and a retard of a phase between input data and an extracted clock signal, and conducts a control to reduce a frequency deviation between the input data and the extracted clock signal. A phase interpolator adjusts a phase of the clock signal subjected to spread-spectrum frequency modulation on the basis result of the frequency deviation in the frequency tracking loop, and outputs the extracted clock signal. In the frequency tracking loop, the frequency deviation between the data signal and the clock signal is corrected to offset a variation of the frequency of the clock signal, on the basis of the frequency modulation information related to the clock signal subjected to the spread-spectrum frequency modulation which is input to the phase interpolator. The frequency of the clock signal seemingly follows the frequency of the data signal.

主权项

1. A semiconductor device having a clock recovery circuit, comprising:
a phase detector that detects an advance and a retard of a phase between input data and an extracted clock signal; a frequency tracking loop that conducts a tracking control to reduce a frequency deviation between a frequency of the input data and a frequency of the extracted clock signal on the basis of a result of integrating a detection result of the phase detector together; and a phase interpolator that receives a clock signal subjected to spread-spectrum frequency modulation from a clock generator, adjusts a phase of the clock signal on the basis of a detection result of the frequency deviation in the frequency tracking loop, and supplies the clock signal to the phase detector as the extracted clock signal, wherein the frequency tracking loop receives frequency modulation information corresponding to the clock signal subjected to the spread-spectrum frequency modulation from the clock generator, corrects the frequency deviation on the basis of the frequency modulation information, and offsets the frequency modulation of the clock signal.