Induction heater #7, and a new half bridge

Bump. ATTN: Terry maybe?

Tim

Tim Williams wrote:

AIUI the strip is your DC bus (it looks like it from the IGBT pinout).

Nice!

hERE'S ONE WAY TO MAKE A LOW esl CAP (damn that caps lock!): see if you cant get a suitably rated axial film cap, then dissolve off the plastic end caps, exposing the metallisation. Then extend your bottom strip enough to attach one end of the cap to, and the top of the strip much more; bend at right angles (running up body of cap) then to top of cap. Voila, low inductance cap.

BTW I wouldnt leave big loops around those gate pull-down resistors, although if you have a nice low-Z connection to the gate driver, it doesnt really matter.

Thats really cool. OK, hot, but YKWIM. Well done!

You'll appreciate this Tim - on my last trip to China, I found a really cool electronics place, and bought 20kG (oops 20kg) of various ferrites (mostly recycled), for about NZ$50. I put them into my Aluminium briefcase (was toolcase), and carried them as hand luggage, which never got weighed. And I had to open the case 4 times for 4 different scanners; there was also a dozen scope probes and some big electrolytics, which put the s**ts up the airport security people ;)

Cheers Terry

Tim Williams wrote: \\ -- Snip -- /

Kind of cool (oops Hot Stuff) there Tim!!

You at Beloit? Also a cool place!!

- mkaras

Ya, you been or something? Some good profs here. :)

Tim

-- Deep Fryer: a very philosophical monk. Website:

Yeah, I have +V, output and -V sandwiched there.

Thanks, excellent news to hear from the eckspurt.

Would that be something like [now] Vishay 735P? My wallet is melting just thinking about it! ;-)

Yeah, that'd do it pretty well!

Ahh, heh those are just to keep the gates ~shorted until I do get the drives in. I'll run short resistors across each IGBT and run twisted pair from the driver to each transistor, keeping the twist all the way up to the emitter.

:-)

Heheh! Like Fred said...try getting into the US like that!

Tim

-- Deep Fryer: a very philosophical monk. Website:

Here's the brand new gate drive circuit. Soldered and tested and debugged and tested one tonight. One left to build. Looks like I need to pick up some more ZTX651 + 751, as I think the '651 was shortish and took out the

Just a bit more complicated than the other...but it works to DC and has a

As shown, it seems to work out to 1-2MHz, depending on the exact values going to the 4401. More current all around would make it go a bit faster, I think I've had it adjusted out to 4MHz before. Fall time is around 40ns (into resistive load) and rise time is 40ns to ~60% followed by a much slower rise over about 50ns to 90%. Humm, I measured those at 20MHz bandwidth, take this with a grain of salt. Suffice it to say more than fast enough, especially against mere 10 ohm gate resistors. Oh, and that was at

Tim

-- Deep Fryer: a very philosophical monk. Website: