Gate driver output going negative

Discussion in 'The Projects Forum' started by k2n2a2, Jan 18, 2013.

  1. k2n2a2

    Thread Starter Member

    Jul 16, 2012
    37
    1
    Hi,

    I used a gate driver from Fairchild (FAN73832) and connected it the way the datasheet shows (image 1),
    and I expected that both outputs high side and low side to switch from 0V to 15V.
    But when I connected the chip and measured the output, the high side output goes from -5V to 10V (level shifted).
    I expected both outputs to switch between 0V and VCC (which is 15V in my case), did I make a wrong assumption
    or is there is a mistake in the way I connected the circuit.
    I would like both outputs (high side and low side) to switch between 0V and 15V.
    how can I achieve that?

    (I attached the oscilloscope images, which are taken between ground and pins 5 and 7 on the device)
     
  2. praondevou

    AAC Fanatic!

    Jul 9, 2011
    2,936
    488
    1st question: Is the your channel AC-coupled? If it is how do you measure absolute DC voltages?
     
  3. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    Chanel 1 of the scope is DC coupled, chanel 2 is AC coupled.
    Put chanel 2 on DC too and see what happens.

    Bertus
     
  4. k2n2a2

    Thread Starter Member

    Jul 16, 2012
    37
    1
    Thank you for the reply,
    I just realized that mistake
    Thank you
     
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