irf520n mosfet driver for boost converter

Discussion in 'Power Electronics' started by bilux, Sep 9, 2016.

  1. bilux

    Thread Starter New Member

    Jul 16, 2016
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    0
    Hello,

    I'm trying to use a arduino due to turn on a n-channel MOSFET (IRF520N) to switch on a voltage of 12V for a boost converter. the arduino due io is 3.3v.

    I have attached the schema of my boost converter.

    but when I run it something went wrong. I belief that the 2N7000 are burned.

    how to correct the driver of the mosfet ?

    [​IMG]
     
  2. ronv

    AAC Fanatic!

    Nov 12, 2008
    3,282
    1,233
    The 2N7000 is pretty marginal for turning on with a gate voltage of 3.3 volts. You might try just a BJT transistor - say a BC547C to drive the FET.
     
  3. RichardO

    Well-Known Member

    May 4, 2013
    1,230
    382
    Why do your meters show 88.8 amps and 88.8 volts?

    At what frequency are you turning the driver on and off at? The 1K ohm resistor might be better as 10 to 100 ohms.

    For safety, you should have a high value resistor from the gate of Q1 to ground so that the transistor is guaranteed to be off while the arduino is being initialized.
     
  4. crutschow

    Expert

    Mar 14, 2008
    12,988
    3,226
    Why do you have two 2N7000's in tandem?:confused:
    If you need a phase reversal, just reverse the phase of the signal from the Arduino.

    Also, per the data sheet, you need at least a Vgs of 4.5V to fully turn on the 2N7000 so you need to use a logic level MOSFET rated for 3.3V, or a BJT as ronv noted.
     
  5. bilux

    Thread Starter New Member

    Jul 16, 2016
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    0
    Hello ronv,

    i found some users using the 2N7000 for voltage level shifter, and i thought it may work.
    i will try to use BJT.

    thank you ronv.
     
  6. bilux

    Thread Starter New Member

    Jul 16, 2016
    5
    0
    Hello Richard,
    the reading on the meters are not true, it's on off status.
    the frequency is 10kHz.
    you are correct, the 1K ohm resistor is better. but i have a trouble in risetime is about ~ 8uS

    thank you Richard.
     
  7. bilux

    Thread Starter New Member

    Jul 16, 2016
    5
    0
    Hello crutschow,

    you are right the two 2N7000's are for reversal.
    i can reverse the phase of the signal from the Arduino. but when the arduino is being initialized, the output will be '0', so the mosfet output will be 12v.
    and the inductance current will get very high.

    i found some articles using the 2N7000 as a voltage level shifter, and i thought it may work.
    i will try to use logic level MOSFET for 3.3V, or a BJT.

    Thank you crutschow.
     
  8. ian field

    Distinguished Member

    Oct 27, 2012
    4,413
    782
    Marginal - but should work (sort of).

    Why can't R2 go to the 12V rail along with R3? Then only Q1 would have "marginal" gate drive. AFAICR: VGSthr is 1 - 3V, so selecting Q1 for a part with a more sensitive gate - or pick a device with lower VGSthr.
     
  9. bilux

    Thread Starter New Member

    Jul 16, 2016
    5
    0
    Hello ian,

    it worked actually, but Q1 and Q2 are burned after a while.

    isn't 12V to much for the Q2 gate?
     
  10. ian field

    Distinguished Member

    Oct 27, 2012
    4,413
    782
    The 2N7000 datasheet says +/- 20V.

    You could easily clamp it with a 5.6V Zener if it worries you that much.
     
    bilux likes this.
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