help

Discussion in 'General Electronics Chat' started by aryam, May 17, 2010.

  1. aryam

    Thread Starter New Member

    May 17, 2010
    1
    0
    hi , am working on a dc dc buck converter . the switch am using is a mosfet IRF740. and i have designed a gate driver with an optocoupler for the mosfet ,because my pwm source is 3v.
    but the gate driver circuit works fine /with a vcc =10/ and the dc dc converter circuit also works fine without being connected to the gate driver .but when i connect them the , it doesnot drive the mosfet .plz help me i cannot find any other fault .
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,646
    2,345
    Hello,

    I moved your post to a more suitable place.

    Can you post the schematics of what you have upto now?

    Bertus
     
  3. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    The IRF740 is not a logic-level MOSFET. You must get Vgs to 10v before the MOSFET is fully turned on.

    I do not know why you are using a high-voltage MOSFET with such a low voltage. It is a poor choice for the job.
     
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