Emisar D4K no stepdown with anduril.2023-05-30.noctigon-kr4.hex

LED Flashlights – General Info 21700 Flashlights
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Hi all,
Hi @ToyKeeper,
My D4K shows no temperature stepdown with anduril.2023-05-30.noctigon-kr4.hex … I flashed this version, did a factory reset, switched to advanced UI and started turbo. After 60 sec. I can’t measure any stepdown (just a little because of the battery) and the D4K got so hot, I could barely touch the head. The temperature blinked out was over 80 GradC.
With anduril.2022-10-21.noctigon-kr4.hex the stepdown works as expected.
@wolfgirl42
I tried your KR4 version from here and got no stepdown either.
My other D4K with boost driver steps down as expected with noctigon-dm11-boost.hex I built on basis of Toykeepers version 721.

Is this a known issue?

Kind regards,
Wolfgang

4 Thanks
Anduril ... 2?
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Could be related to the other recent thermal regulation bug which only affected the kr4.hex versions AFAIK.
I run anduril.2023-05-17.noctigon-dm11-boost.hex on my D4K boost and there are no issues with stepdown.

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I just checked my other D4K with boost driver. The stepdown works as expected with noctigon-dm11-boost.hex I built on basis of Toykeepers version 721.

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Hi @ToyKeeper
Hi @wolfgirl42
I built a few KR4.hex version and found out, that the bug was introduced in revision 714. In revision 714 only 2 files were changed …
in cfg-noctigon-kr4.h is missing:

#define MIN_THERM_STEPDOWN 66  // must be > end of dynamic PWM range

I added this to version 714 and then it steps down correctly.

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Congrats, and nice work! :beers:

Edit: Looks like in ramp-mode.h, if MIN_THERM_STEPDOWN is undefined it defaults to MAX_1x7135 (kind of an obsolete symbol name, but used to refer to max regulated power in general now), which is 130 on the KR4. So it steps down out of FET, but stays at max regulated no matter how hot it gets, which isn’t ideal, I think it’s just reality failing to keep up with the design in that when 7135-based drivers were more of a thing, lights used multiple of them, so a single chip was a sensible target to stop stepping down at. The KR4-nofet has MAX_7135 at 150 as it’s since become “max regulated power” in general, in which case it never steps down at all. It could probably be fixed more robustly but the multichannel refactor already has a todo there so probably not worth the effort to add some kind of logic to detect a condition that will never allow stepdown, but I can create some temporary builds with the fix if anyone wants them.

3 Thanks