I've not done this yet (it's on my list) but I talked to an expert a while
ago and he said that what you do is put the system on a bench supply and
dial the current way way down, then start reducing the time and you'll
actually see the shoot-through on the scope.  Just dial back from that poin=
t
and you're good to go.

again, I've not tried it, so be careful.

DougM

On Tue, Mar 15, 2011 at 8:47 AM, Ing. Marcelo Fornaso <mfornaso@yahoo.com>w=
rote:

> Dear Sirs,
>
>
> I'm building something like a Segway (plus a little twist).
>
> It's PIC based (old 16F877) and the microcontoller plus sensors board and
> software are already done and working, ready for live tests.
>
> I would like to build an OSMC controller, but here (in Buenos Aires) the
> HIP4081A bridge driver is not easy to get.
>
> So, I designed and built a similar controler board, but using pairs of
> IR2110
> instead.
>
> Double IRF1407 MOSFETs at each branch (total of 8 for each full H bridge)
> to
> handle plenty of current (I think 50 A. on the safe side, 36 V.).
>
> For lock antiphase drive (20 KHz. PWM) I'm not installing free-wheeling
> diodes,
> but the three 1.5KE51CA TVS's are connected the same way as in OSMC
> schematic,
> for protection.
>
> Load will be an (overpowered) electric wheelchair motor.
>
> I designed RC networks at IR2110 inputs for 1 us delay between high or lo=
w
> side
> turning off and the other in the same branch turning on, to avoid
> shoot-through.
>
> Everything is running wonderfull by now.
> With reduced voltage and low load the osciloscope shows nice and almost
> squared
> output signal: V+ for a while, 1 microsecond off, then V-, and another 1 =
us
> to
> complete the 50 us PWM period.
>
> I'm referring here to the total final delays. The MOSFETs gate driving
> include a
> schottky diode (1N5819) in parallel with 15 Ohm for each mosfet, for easi=
ng
> cutt
> off.
>
> My question here is about those 1 us delays. Do you think they are OK? Ar=
e
> they
> too short/long?
> More than some Web comments, I have not a clue for better design.
>
> Your comments will be appreciated.
>
> Thanks and regards,
>
> Marcelo Fornaso
>
>
>
>
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