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Cheap N-type MOSFET for PWM driving many LEDs with 3.3 V logic?

Discussion in 'Power Electronics' started by seanspotatobusiness, Dec 13, 2018.

  1. seanspotatobusiness

    seanspotatobusiness

    185
    4
    Sep 11, 2012
    I'd like to copy this project to automate some RGB LED strips. It calls for some N-type MOSFETs to turn on and off LEDs in a pulse-width-modulated way. What would be some suitable MOSFETs that can permit at least 1 A? I know I could find something myself but I wouldn't know whether it was some niche product that I'd be overpaying for compared to another model of MOSFET. Thanks.
     
  2. seanspotatobusiness

    seanspotatobusiness

    185
    4
    Sep 11, 2012
    I think the answer is RFP30N06LE or FQP30N06L.
     
  3. Bluejets

    Bluejets

    3,043
    595
    Oct 5, 2014
    Or drive the gate via a transistor and higher gate voltage, say from the lamp supply .
     
  4. WHONOES

    WHONOES

    578
    113
    May 20, 2017
    If you are going to drive the FET's directly from 3.3V logic, the Fet's will not be fully enhanced and indeed may not even turn on depending on the gate threshold voltage. With the first of your suggestions, having had a look at the datasheet, it would be about 1/2 on with consequently higher on resistance and hence power dissipation plus you LED's may look a bit dim.
    Bluejets suggestion should be considered.
     
  5. (*steve*)

    (*steve*) ¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd Moderator

    25,011
    2,610
    Jan 21, 2010
    Here is the start of a resource that may help you. At the moment I've just linked to various related answers I've given, but the general principle is stated in the more detailed ones. Soon I will continue this with generic advice.

    I hope that helps.
     
    BobK likes this.
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