SELF-DIAGNOSTIC CIRCUIT FOR MONITOR AND ITS METHOD

摘要

PROBLEM TO BE SOLVED: To provide a self-diagnostic circuit for a monitor incorporating a check circuit and its method. SOLUTION: A circuit is made up of a video preamplifier and PLL circuit 20, a 1st signal shaping section 31 that shapes an output signal of a video main amplifier circuit 30 connecting to the circuit 20 and feeds back the shaped signal to the circuit 20, a horizontal oscillation and PLL circuit 50 that compares a horizontal synchronizing signal/vertical synchronizing signal received from a connector 10 with a horizontal synchronizing signal/vertical synchronizing signal fed to a CRT so as to detect a phase difference, a vertical oscillation and PLL circuit 70, 2nd, 3rd signal shape sections 61, 81 that feed back a signal to the circuits 50, 70, a 4th signal shaping section 91 that shapes an output voltage of an SMPS 90 which supplies a drive power supply to each circuit of the monitor, and a microprocessor 100 that receives the horizontal synchronizing signal/vertical synchronizing signal from the connector, output gain information and a phase difference signal from the circuits 20, 50, 70, and an output voltage of the SMPS 90 via the 4th signal shaping section, discriminates the presence of abnormity of each circuit and transmits discriminated data externally from the connector 10.