Hence the mosfet circuit will be operated at active region for constant current mode,then what about the constant voltage mode for battery charger applications?

 

what about the constant voltage mode for battery charger applications?

The first thing I thin is, The goal of a battery charger is to provide a constant voltage across the battery, not the mosfet. Without a circuit diagram, I can't understand what you are asking.

 

The first thing I thin is, The goal of a battery charger is to provide a constant voltage across the battery, not the mosfet. Without a circuit diagram, I can't understand what you are asking.

Thanks for reply,
I don't have any circuit diagram,just asking whether mosfet or igbt will provide a constant voltge.

 

just asking whether mosfet or igbt will provide a constant voltge.

Not all by their self. A circuit can provide constant voltage, a shunt regulator can provide constant voltage, but a mosfet or an IGBT can not do this all alone.

 

If by active region, you mean the highlighted region shown here for a typical mosfet:


Note that in that region, the mosfet behaves like an Ohmic device. As current increases, the voltage drop across the Drain-Source increases and visa versa. Therefore, by itself, it will not provide constant voltage anymore than a resistor would.

John