CIRCUIT FOR PREVENTING MALFUNCTION OF LCD MONITOR

摘要

PURPOSE: A circuit for preventing a malfunction of an LCD monitor is provided to detect a composite synchronous signal stably without regard to a signal pattern and a signal level in a SOG(Synchronous signal on Green) signal. CONSTITUTION: An amplification unit(10) comprises a transistor(Q1) whose turning on/off is determined by receiving the SOG signal through a base, and the first capacitor(C1) connected to the base of the transistor, and the first resistor(R1) whose one end is connected to a collector of the transistor and another end is connected to a supply power, and the second resistor(R2) whose one end is connected to an emitter of the transistor and another end is grounded. A clamp unit(20) comprises the second capacitor(C2) connected to the amplification unit, and the first diode(D11) whose cathode is connected to the second capacitor in parallel and the third capacitor(C3) whose one end is connected to an anode of the first diode and another end is grounded. A clip unit(30) comprises the second diode(D12) whose anode is connected to the clamp unit in parallel and the fourth capacitor(C4) whose one end is connected to a cathode of the second diode and another end is grounded. And an integration unit(40) comprises the third resistor(R3) connected to the clip unit and the fifth capacitor(C5) whose one end is connected to the third resistor in parallel and another end is grounded.