Thanks for the review.
What the PAM2803 has is not what we’d normally refer to as temperature regulation. It has “Over Temperature Protection” which kicks in at 150c. The recommended operating temp range is –40c to +125c junction temp and an absolute maximum ambient temp of +85c. What you are seeing is not the chip proactively trying to reduce the temperature, it’s the chip reactively trying to prevent an outright failure while already operating above the absolute maximum temperature. The reason that it goes back and forth slowly rather than flickering is due to the 15c hysteresis. “Over Temperature Protection” should trip at 150c and not un-trip until 135c due to the hysteresis. The datasheet isn’t the be-all and end-all, maybe it will survive forever like that. My intention with the above is simply to help you better understand what the datasheet says.
See above RE: “survives”. That said, I think that 2xAA or 2xAAA will be fine. After quickly examining the pics over in this thread: Фонарик BLF 348 Nichia NVSW219BT - V1 (post#11 by MSS) we see that the driver is using a 0.5ohm sense resistor. That’s perfectly reasonable (about 0.19A output - exactly as one might expect with the output measurements). While the driver may be unregulated for part of the discharge, the amperage should not be high enough to cause any temperature problems. Swapping in a smaller sense resistor could help maintain regulation (more boost).
Does anyone have any opinions on these BLF-348 units w/ the Nichia emitters vs the previous GB lights from _the_’s GB over here: STARTED: GBGB: Stainless steel AAA clicky with a clip (CQG S1 “clone”) ?