Title:
PHASE DIFFERENCE DETECTING CIRCUIT OF LIQUID CRYSTAL DISPLAY ELEMENT
Document Type and Number:
Japanese Patent JP3538682
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To obtain a stable screen display even when an external composite synchronizing signal is inputted by cutting off the output of a phase difference detection signal in an equalization section and outputting the phase difference detection signal normally in other sections.
SOLUTION: A phase comparison part 100 generates a phase difference detection signal PFD by comparing the phase of the external synchronizing signal Csync with an internal synchronizing signal. An equalization pulse detection part 200 inputs a horizontal synchronizing signal Hsync and the external Csync to detect equalization pulses and then generates a control signal CS for controlling the output of the phase difference detection signal PFD with the equalization pulse detection signal DFT. An output selection part 300 outputs a signal for cutting off the output of the phase difference detection signal PFD in the equalization section with the control signal CS and outputs the phase difference detection signal PFD from the phase difference comparison part 100 in other sections. An equalization section end detection part 400 detects the end of the equalization section and outputs an equalization section end detection signal DETC to an equalization pulse detection part 200.
Inventors:
Yeo, Jeong Beom
Application Number:
JP18387698A
Publication Date:
June 14, 2004
Filing Date:
June 30, 1998
Export Citation:
Assignee:
HYUNDAI ELECTRON IND CO LTD
International Classes:
G09G3/20; G02F1/133; G09G5/00; H03L7/085; H03L7/087; H04N5/12; H04L7/033; H04N5/66; (IPC1-7): H04N5/12