SELF-CORRECTING CIRCUIT AND METHOD FOR CORRECTING PHASE OFFSET BETWEEN RING OSCILLATOR OUTPUT WAVEFORMS

摘要

PROBLEM TO BE SOLVED: To provide a circuit and a method for correcting phase offset between ring oscillator output waveforms. SOLUTION: This self-correcting circuit consists of a voltage-controlled oscillator adjusting and outputting the transition time of an output signal by a control voltage input for controlling the phase offset, a frequency divider performing a small number of frequency divisions of an output frequency of the voltage- controlled oscillator with various phase output waveforms having the same phase difference, a phase-locked loop circuit including at least a phase frequency detecting means for comparing the frequency and phase of the frequency of a signal subjected to frequency division with the frequency and the phase of a system clock and outputting the comparison results, and a phase offset correction loop circuit to which the comparison results are inputted from the phase frequency detecting means and which detects a phase offset between voltage control oscillator output waveforms and generates a control voltage for controlling the detected phase offset to be outputted to the voltage-controlled oscillator, is for correcting the phase offset between ring oscillator output waveforms and eliminates the phase offset between the ring oscillator output waveforms.