5V TOP414G 2A isolated switching power supply circuit
Posted on Dec 11, 2010 9780
Constituted by a 5V TOP414G, 2A output isolated switching power supply circuit is shown. C1 is the input filter capacitor. VDz VD1 composition and primary clamp protection circ
uit. The control terminal of the resistor R1, C2 is a bypass capacitor. TOP414GC-S parallel between the end of the C10 is to prevent high-frequency interference appears on the control side sometimes cause power outages trigger circuit malfunction. VD2 output rectifier diode, output filter C3, C4, L, C5 and C6 constituted, C9 as an output capacitor noise cancellation. External error amplifier by a TL431 shunt regulator composition. When the output voltage fluctuates, by R3, R4 after the voltage obtained by dividing the sample voltage, the TL431 with a reference voltage, and generates an external control signal, and then to change TOP414G control terminal current through optocoupler PC817A, thereby regulating the duty than make Uo stabilize. Control loop gain is set by R2. After the feedback winding voltage VD3, after C7 rectifier to PC817A the infrared receiver power supply.