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Thread: Mosfet gate driver recommendations for Teensy 3.X lines? Overview gen question

  1. #1
    Senior Member
    Join Date
    Mar 2013

    Mosfet gate driver recommendations for Teensy 3.X lines? Overview gen question

    Hey, so I'm noticing on a number of my regular projects the only downside to switching to the 3.X teensies has been the 9mA/25mA MAX 3v3 drive potential of the pins. This compares to the 5V 20mA/40mA MAX of most of the arduino AVRs. In the latter case I found I had decent performance characteristics from a large variety of logic level mosfets. In the teensy case I'm nervous about driving the more limited selection of logic level power mosfets at increasing frequencies, because I suspect I'm driving them really poorly and don't have the scope tools (or background E.E knowledge) to figure out how badly I am driving them or what my max frequency can be (i also worry that i flirt the edge of the Vgs min and Vgs max tolerances on the fets). I've tried reading a few application notes and now understand more, to the point that I know I don't understand enough (apparently, it's not entirely as simple as just charging a capacitor)

    Long story short, does anyone know how to approach finding a "good" mosfet driver for general teensy applications? I'm hoping to drive some N-mosfets at 30kHz, or even higher if it's possible with a proper driver. That would be above the AVR speeds I was using (which even with the much better 20mA driving current I didn't bother going above 10Khz in most cases.) I also would hope it wasn't smaller than SOT-23 or SC70 with respect to ease of hand soldering SMD components.

    I tried so far searching "teensy mosfet driver recommendations"
    I tried going through the octoparts common parts library (seems lacking any recommendations)
    And I have tried once or twice going through digikey, but have limited confidence in my approach to qualifying the drivers.

    So I expect my question might result in either an answer of the category
    "Here is an industry standard driver, to mosfet drivers as LM317 is to linear regulators [or something like that]"
    "Here are the type of characteristics you look for when filtering digikey/mouser/elsewhere options for mosfet drivers"
    "Other categories of response"

    Hopefully I've managed to narrow down the scope of the question in a way that is still useful to a lot of people getting started with "powering powerful things with the teensy." I've taken for basics that people understand a little about mosfets, N vs P, etc, and if they don't, I recommend the adafruit tutorials on mosfets they were fun and helpful for me to understand a little bit about g-s-d type principles.

  2. #2
    For most applications I like the MIC5018 because it has a charge pump that generates enough voltage to fully enhance most NFETS. But since you need speed, it isn't appropriate.

    The MIC4416 can drive more current but doesn't have a charge pump to boost the supply voltage so it is limited by what you provide.

    But there are lots of FET driver ICs out there so look around until you find something you like.

  3. #3
    Senior Member
    Join Date
    Mar 2013
    Thanks UhClem! That totally works as a response. As it stands I think I interpret your response as a more generic tip for two options, and the more global statement that there are a lot of options and no single "best" or "goto" way to approach it. That makes sense to me, and it's also reasonable that gate drivers might be closer to a commodity part in some ways.

    Sometimes with things like this I post the question because I don't know what I don't know. And so it helps a lot catch if people respond with a lot of tips about "common gotchus" that a more traditional E.E background would teach me about.

    I recognize I still need to determine whether the characteristics of that gate driver are compatible with my whole setup, but I think I can manage.

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