Frame pulse signal latch circuit and phase adjustment method

Abstract

A frame pulse signal latch circuit has: a pulse-width expanding unit which outputs a frame pulse signal FPIN having a pulse width longer than a m-clock cycle; a phase adjustment unit which generates a phase-adjusted output clock CLK'; a flip-flop which latches the frame pulse signal FPIN; a racing detection unit which generates signals, which are shifted by one to m clocks with respect to a frame pulse signal FPOUT, and detects a racing state based on a result of an AND operation of the frame pulse signal FPOUT and the clock-shifted signals; and a control unit which sequentially selects and directs different phase adjustment amounts to the phase adjustment unit, determines an optimal phase adjustment amount based on a worst phase adjustment amount of the case in which the racing state is detected, and gives a direction about the optimal phase adjustment amount to the phase adjustment unit.