FAN7371 highside driver

Discussion in 'Electronics Resources' started by shortbus, Oct 17, 2009.

  1. shortbus

    Thread Starter AAC Fanatic!

    Sep 30, 2009
    Has anyone used a FAN7371 highside driver?

    How do you figure the values for the bootstrap components?

    What diode to use?

    I checked on Fairchilds web site and couldn't find an app. note. Can someone please help me with formulas or rules of thumb for component values?

    Thank you, cary
  2. Thav


    Oct 13, 2009
    I haven't ever found an app note on this either.

    What I do is find the input capacitance of the FET, usually given as Cis or sometimes Vgs and multiply by ten to get my boost cap. If you make it too large it may take a few switching cycles for the boost voltage to get high enough to fully turn the FET on and that's something that could be destructive. If you need to limit the inrush current to the capacitor you can add that Rboost that datasheet shows.
  3. shortbus

    Thread Starter AAC Fanatic!

    Sep 30, 2009

    Thank you for the reply. What voltage should I use for the capacitor?

    My Vb is 12VDC. Vdd is 12VDC. Vs is 100VDC. So what should I use for my cap voltage?

    I was going to use a IR2110 for my driver, but I only need the high side. Would it be OK to use the app. notes for the IR2110 for the resistor values?

    Do you have a schematic that you could post showing how you used the FAN7371? Or do you use another driver in what you do? If so what driver do you favor?

    This is my first attempt at using Mosfets as a switch.

    Thank you, Cary