Battery Charger for Various Devices

The project can be implement in various field. Especially I design for battery charger. Because battery charging has played important role in recent years. All of electric cars, UPS, generators have battery and it has to charge. The projects features are; it can supply from wide range AC line, and its efficiency is very high, it has over current protection. For PCB designi I used Altium Designer.

The circuit has full bridge rectifier for smooth DC link voltage. And because of drawing high current when bulk capavitor voltage is fully no charge, I used a NTC for inrush current limit. The topology of converter is Flyback. In flyback has seriously high voltage spike in mosfet drain terminal. Therefore I put a RCD clamp circuit. When the primary side is no conducting, the inductor of polarity will be opposite and the current will complete via a diode and capacitor and resistor. And driving of mosfet, I used a PWM analog IC which called UC3845. The features of this IC is that current mode control, and over voltage shut down. Moreover the design is isolated so I use optocoupler and transformer. The transformer of design is very crucial and windind of it is very challange. When the charging of primary side of inductor which is part of the transformer, the secondary is not conducted. The energy is deposite in gap of ferrite. After this period the energy is transfered to secondary side.