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Re: RAMPS for Due!

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Cefiar
Changing the resistor on the drive FET to something smaller would most likely improve the switch-on time, though since we've changed the design currently to running direct off the buffers, that seems a moot point.

Would be interesting to see how this changes with the new circuit we've got using the 74HCT/ACT series buffers. If it turns out the performance is very poor, then perhaps we could investigate the TC4426A/TC4427A chips mentioned earlier in the thread.

I hacked up a circuit on a spare board, using a 74HC244 running at 5V driving the IRLB8743 directly, with a square wave generated by an Arduino Mega.

[attachment 23503 DS0003.png]
[attachment 23504 DS0004.png]
[attachment 23505 DS0005.png]

Switch on and switch off are now around 300-400 ns.

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