THERMAL SHUTDOWN UNIT, SWITCH CONTROLLER COMPRISING THE SAME, AND CONTROL METHOD OF THERMAL SHUT DOWN PROTECTION OPERATION

摘要

PURPOSE: A heat shielding part and a switch control part including the same and a heat shielding protection conduct control method are provided to control heat shielding protection conduct according to load without a separate sensing circuit by using heat shielding reference voltage according to the operation state of a switching mode power supply. CONSTITUTION: A bridge diode(100) creates input voltage(Vin) by spreading and rectifying an input alternating current power source(AC). A transformer(200) comprises a primary side coil(Co1) and a secondary side coil(Co2) which is connected to load. A feedback circuit(300) creates feedback information corresponding to output voltage(Vout) and transfers to a switch control part(400). The feedback circuit comprises a shunt regulator(301), a transistor(303), and a feedback capacitor(304). The switch control part controls the switching operation of a power switch according to feedback voltage(VFB).