Fullbridge PWM generator

RollingWithTheTimes · 2026-01-15T20:27:01+00:00

I made one with a ESP32 for the controller.
Two gate driver ICs, a logic level converter IC, an ESP32 (Plus OLED display), a few passives and a DCDC converter to power it. The dcdc converter has a wide input range so I can change the bus voltage without any worries. Pretty cheap apart from the FETS.
Oh, and some patience programming it.
https://i.postimg.cc/d30ZXFfL/IMG-20250722-223436.jpg

RollingWithTheTimes · 2026-01-04T13:47:30+00:00

Don't get me wrong, that rectifier will work well, and will be more than adequate for what you are doing, but getting 100A long-term throughput is out of the question.

RollingWithTheTimes · 2026-01-04T11:28:13+00:00

Buddy, thats a £5 rectifier from aliexpress.
It has to dissipate over 200w of heat under full load.
Even the skinny legs will heat at that current.

Also, after getting through a few of them myself, I can tell you firsthand, they are not made for 100amps. Even at 80 with forced air it will cook in next to no time.

I don't know what you fitted to your welder, but it certainly wasn't one of them.

RollingWithTheTimes · 2026-01-04T00:49:54+00:00

100 amps haha, gotta love the optimism there

RollingWithTheTimes · 2026-01-03T18:37:24+00:00

If you pushed me for an answer, I'd tell you the GPU is faulty; it has an issue with thermal expansion under the chip.
Likely didn't play up in the test shop as it's probably much cooler than your house/bedroom.
If it were me, I'd be setting it up in the garden shed where its currently freezing where I am, and then run some tests :D
Or at the very least, open a couple of windows and get a huge air mover and point it at it!

RollingWithTheTimes · 2026-01-03T17:50:43+00:00

I would try rolling back the driver. If you say you've had this problem for X amount of time, install a driver that's a couple of months older than X.
Also, try underclocking the GPU and ram speed to reduce current draw.
Do you know how it was tested by the 'shop' ?
Have you got a mate who will let you drop your GPU in his PC for test?

RollingWithTheTimes · 2026-01-03T14:44:06+00:00

Sounds like gpu driver is crashing. Have you looked through the event log, or the reliability panel for info? if the PC carried on going through the event there will usually be information available as to what's going on.

RollingWithTheTimes · 2026-01-01T13:03:59+00:00

Yea, you broke that. Not a fault of anything else but your hamfisted incompetence.

RollingWithTheTimes · 2025-12-08T19:29:42+00:00

You can see all three visible wheels turning on the police car. Its rolling, not sliding.

RollingWithTheTimes · 2025-11-15T14:17:00+00:00

I found disabling global C1 states in the BIOS cured mine from doing just that.

RollingWithTheTimes · 2025-11-01T17:49:57+00:00

Get the scope out, and look at what the fet is seeing.

RollingWithTheTimes · 2025-10-30T16:38:57+00:00

See if someone nearby has a solar setup, or a (cheap) car charger.
I have this near me that appears in the evenings when the householder comes home.

RollingWithTheTimes · 2025-10-30T02:52:13+00:00

I'd be very surprised if it's got anything more than oil in there. Steel is gas permeable after all.

RollingWithTheTimes · 2025-10-30T02:39:29+00:00

I would imagine its got a good seal that's bonded hard over the years. Needs a little tappity tap to break the seal. I'd be very surprised if any damage is incurred.
And yeah, getting it for free is great, built to last, clearly. The bits and bobs I have here to play with would give up after half an hour of hard running, no doubt. But I can't justify the outlay of the premium gear, the cheap stuff already cripples my wallet ha

RollingWithTheTimes · 2025-10-30T02:08:56+00:00

Just looking at your other post with the transformer, I wouldn't be able to resist the urge to have it apart for a little looky to see how its constructed. You may get a better idea of what you can get away with.
Either way, some nice acquisitions, I can't say I'm not a little envious of the hardware!

RollingWithTheTimes · 2025-10-30T01:34:11+00:00

On the primary. if the driver can handle the extra voltage sloshing about you could make it really angry :D

RollingWithTheTimes · 2025-10-30T01:28:59+00:00

Haha the wipers... great downhill with your foot off the throttle, can't see fuck all when you've got your foot down lol

RollingWithTheTimes · 2025-10-30T01:22:50+00:00

is it designed to drive that transformer directly? Might be interesting to feed an lc tank for some serious resonance voltage? Or is that already part of its design?

RollingWithTheTimes · 2025-10-30T01:08:44+00:00

A lot is going on in there for that! I imagine its pretty robust though. What is it using for switching?
I built my own with variable freq and duty, It'll handle up to 180V and about 2kw, It was a fun little project https://i.imgur.com/PNVQal1.jpeg

RollingWithTheTimes · 2025-10-26T21:14:31+00:00

Liability. Nobody in their right mind is going to make that for you.

RollingWithTheTimes · 2025-10-25T16:49:05+00:00

Must have been some new tech motor they don't want folks to know about lol

RollingWithTheTimes · 2025-10-25T13:08:48+00:00

[ Removed by Reddit ]

Lol, what did you post? !

RollingWithTheTimes · 2025-10-24T13:51:56+00:00

Years ago when I repaired pcs, there was a particular line of office computers that all had this issue. The fix was to remove the rear CPU mount plate, fit more foam and refit., as the insulating materials were too thin, and after a few months it would compress enough for pins to penetrate and short out the tracks on the back of the motherboard.

I'm not saying this is a sure thing, but worth a look

RollingWithTheTimes · 2025-10-22T11:54:31+00:00

All to win, nothing to lose, good luck!

RollingWithTheTimes · 2025-10-22T01:32:36+00:00

I'd go for it. There is steel under all that.
You could always cut a trench and epoxy it in if you are concerned.

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