OVER POWER PROTECTION CIRCUIT OF A MONITOR

摘要

PURPOSE: A power protection circuit for a monitor is provided to prevent the damage of parts due to over power pressure by discharging the electric current flowing in the photo coupler with an earthing in case the over power pressure occurs. CONSTITUTION: The circuit comprises a direct current supply part(1) which transfers the alternating current into the direct current and supplies to the transistor(2); a control IC(4) which makes and outputs the PWM control signal by a feedback current; a power transistor(3) which is put on/off by the control signal and makes the alternating current at the transistor(2); and an output part(5) which transfers alternating current into direct current and supplies to the circuit of each monitor. The circuit further comprises a sensor part(10) which outputs over power sensor signal(S1,S2,S3); an operation part(20) which outputs the operation signal; and a switching part(30) which discharges the current in photo coupler in earthing.