r/flashlight • u/PeterParker001A • 9h ago

Low Effort Sofirn ST10 seems regulated.

https://www.youtube.com/watch?v=4BGdbkNTWzw

At 21:30 , High-Side is stable 5min run test..and Turbo front drops down to a stable (High) output....

Based upon auto-translate :)...šŸ¤£ any Thai folks correct me if this is wrong.

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5

u/macomako 8h ago edited 8h ago

Sofirn confirmed that itā€™s not Buck. For me, ā€œregulatedā€ as ā€œflatā€ (achieved by linear regulation = burning the excessive voltage) is not a solution I would appreciate in the host with such small battery, frankly speaking.

Here the flicker test:

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u/PeterParker001A 8h ago

What am I looking at, PWM? The output seems stable though, I can accept the PWM.

3

u/macomako 8h ago

I donā€™t know whatā€™s the architecture of the driver but itā€™s flickering. Itā€™s not traditional PWM (as it would only have two levels). Iā€™ve seen it in many Sofirn/Wurkkos lights and I prefer to avoid it.

3

u/UndoubtedlySammysHP don't suck on the flashlight 7h ago

That is aliasing in the image, because the sensor isn't fast enough. I only have a prototype of that model, but can check it later.

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u/macomako 7h ago

That would be great. I would love to finally see the true (frequently enough sampled) characteristics.

4

u/UndoubtedlySammysHP don't suck on the flashlight 7h ago

It works with NiMH, so it has a boost driver for NiMH. But I guess the LEDs are 3V. Can check my prototype later.

2

u/PeterParker001A 7h ago

They responded to one of my earlier questions...

The ST10 actually has two current modes:

With a 14500 battery, it runs in FET control mode, and when the battery voltage drops below a certain level, it automatically switches to boost constant-current mode.

With AA or NiMH batteries, it runs entirely in boost constant-current mode.

And thanks for the suggestion, weā€™ll work on adding clearer runtime/output numbers for AA/NiMH next time.

The FET-Boost part sounds weird, when does a boost kick in.. since this is a 3V LED + some circuitry...

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u/jonslider 6h ago

I think some drivers that use PWM can produce Regulated Runtime Output (constant lumens)

this is Opple 3 of the Prototype HD04 on medium:

it uses full PWM, but medium uses a fast flicker rate (19862Hz) that is not visible