How big of a resistor?
How big of a resistor do you think should be used on the FET Gate?
Hi robologist,Interesting
Hi robologist,
Interesting points… I was surfing around trying to find what might make the bridge full reverse shock proof . I have mostly seen protection diodes wired to the drain of the FET as you mentioned previously. If the FET is clamped by an adjacent diodes, are all the other diodes necessary? I think we are all interested in the Most Robust / the Fewest Components sweet spot.
As above, or maybe a little more
Check the post just above . 10 ohm is about the minimum, might go as high as 50, but not higher for use with the TC4427 driver… If you check the OSMC resistors, they are 150, but they are four 150 ohm resistors essentially in parallel. So the effective resistance the HIP4081 driver was seeing was 37.5 ohms. Ohms law 12v/37.5 = 300 mA forward current to average the higher reverse current (through the diode), to keep the HIP4081 cooler. If you don’t use the reverse diode, you can have a smaller resistance for a greater current both ways, so that’s why I went as small as 10 ohm.
Reverse diodes
I see the additional reverse protection diodes as useful if the FET reverse breakdown voltage is less than twice the supply voltage, otherwise I’d just use the FETs intrinsic diodes. As above, the OSMC if running a 36 volt pack or even higher up to 50v, is dangerously near that 55 volt reverse breakdown of the IRF1405s. If it was never to run more than 18 or so volt pack, the external TVS diodes probably wouldn’t be needed.
This is getting more towards opinion, as I can’t exactly spell out why that point is. I really prefer to provide a factual back-up as to why I picked the “double” figure, but can’t lay my hands on it right now.
Nice one!
COoOL
So is this the driver you’re
So is this the driver you’re gonna use with the wheelchair motors? Can it handle the Amps (24ish)?
10amp motor control circuit
i want to make a 10 amp motor control circuit just want to be able to drive it in both the direction two motors and ten amperes per motor any ideas pls help
voltage regulators?
If those TO-220 devices to the right of your main pic are voltage regulators in parallel, then you could have a problem there. Since the regulators aren’t all exactly the same, the reg with the lowest threshold will take the full load until it burns out, and then the next lowest keyed reg will take the full load and so on.
High Current voltage regulation
If this is not the case then forget i said anything, it’s too late in the night for me to read this massive page.