smps with charger

26 Apr 2006 7:43 Re: this will work??(suggestions please)

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refer the circuit,,,,,task is mosfet should turn off sharply when ac is not prsent.

let me explain my requirment,,,

when AC present VCC1 will be prsent (from AC-DC converter which i mention as

DC source.)this VCC1 is the source for the battery charger and DC-DC converter

(which is connected to VCC)whether AC is present or not DC-DC converter should

be ON.,,,,,,,,

when AC-DC ON it will feed power to the dc- dc converter and charger,,,,,

when AC is absent battery should feed the power to the DC-DC converter,,,


here my requirment is when AC is absent i want to isolate AC/DC from battery

(from VCC) I can achieve this with out mosfet it self ,,,,,,, i can use a diode

instead of MOSFET refer circuit 1........ but loss will be more (compare to MOSFET)

since i want to achieve much higher efficiency i want to replace the diode with a

MOSFET ,,,,,, so think in that way ....,,,,, better ideas and suggestions will be really

appreciated

kamal :wink: