Mike only told us about this early this morning, remember:
Thu, 05/12/2016 - 10:07
Thank you Mike.
Now we have two more data points, mine and DB C’s.
Going forward, it’s something to watch for.
Looking back, and looking at what’s currently advertised for sale — time will tell.
I know nothing about any of the electronics so I’m done. I trust the folks here who know stuff to work it out and educate the rest of us.
It’ll take time.
The spec sheet’s do indeed call for the 20SSU to have a range of 2.8V to 5.5V. The 10SSU is rated at 1.8V to 5.5V. What that might mean to how the light actually functions is not within my capabilities but I’ve posed the question to some that might know.
Sensitivity that I’ve seen is some Bistro drivers do not want to work at high load levels or high current draw. They bump back down to moon. And these invariably will not allow a tail cap current test beyond level 4, maybe 5. Full Turbo wont’ measure, it just bumps down to moon. I don’t know exactly why, and it’s done it even on some of my own builds from scratch on OSHPark boards with premium components.
Digging…
ToyKeeper tells me “the trailing edge of a FET pulse was actually creating an over-voltage condition for a moment, causing the MCU to reset. It wasn’t an under-voltage thing. A different FET can fix it, or an added resistor, or a bigger C1.”
She also said she’s tested the 2.7V variant down to 2.68V with no issues and believes the LVP is set at 2.9V from Manker. This shouldn’t be an issue but she agree’s that the 10SSU might be a better overall choice. I’m trying to determine what resistor value and where, but have used higher cap values at C1 to no avail on a couple of my own builds and on one troublesome sample driver from Manker.
Will let y’all know as I find out…
The Schottky diode eats up to 0.3 volts, so 2.9 volt as switch off limit seems still to low.
So the precautionary question — what’s the worst that could happen?
Is this — a known substitution not worth mentioning as it makes no practical difference, or
— an undisclosed modification that y’all didn’t know happened and now want to understand? Or
— a surprise to find in production drivers, but you already know isn’t a big deal for us end user type people?
I wondered when I read
but that possible worry was raised a year ago with no further mention I can see — long since an old question. Not to worry?
People often bring up that the 10SSU (attiny25v) is 1.8-5.5v but miss the fact that atmel says you need to use 4Mhz max for the 1.8-2.7v range. And none of the current firmwares implement 4Mhz. (4Mhz code)
Aka: the minimum voltage is 2.7v (with the current firmwares) regardless of whether you use attiny25 or attiny25v.
The ATtiny13a runs with 4.8 Mhz and is fast enough for everything, so I don’t see any problem running the 25V with 4 Mhz.
I would like to do some tests with this mcu’s but unfortunately I have only 25_V_ for my breadboard and no 25_V_ in the small package for the driver PCB. Will order some today. Never desoldered this small things, what’s the cleanest and cheapest way to change the mcu on the PCB? I don’t mind if the desoldered one get’s destroyed.
I really wouldn`t be astonished if the problems with the X5/X6 disappear with the right driver and frequency.
I suspect using 4Mhz may very well improve reliability of even the attiny25.
And that means 3 volts from the battery because of the power drop at the schottky diode. At 2.7 volts from the battery the mcu will be at 2.4 volts!
The fuse settings I found in Toykeeper’s bistro code indicate a brown-out detection at 1.8 volts.
Hi,
did you test a MTN 17DDm Driver with Bistro UI under high loads already? I plan using that one with some triples. Now i am confused if the driver will work with high currents.
Regards
Kenjii
I have taken a X5/X6 driver from the group buy and put it in a triple build with warm white 219C leds and a Efest 18500 IMR battery, all resistances minimised (mod post here, #484 in the what did you mod today thread). It runs over 10A with no problem (judged from the light output of 2000+ lumen OTF), but if the tail is removed and replaced with a copper sheet loop to measure the amps with a clamp meter, the bump to moon problem occurs and I can not do an actual measurement.
So I’m not sure what actually happens but 10A seems no problem.
It has been reported that Richards MTN drivers don’t display the same characteristics as the Manker built versions. His board design is different and seems to yield a more robust driver.
I have the Bistro pushing some high output lights with no issues, even have a couple that show full tail amps well up over 12A.
ATtiny25 with or without “V”?
The only 2 readily available samples of Richards FET+1 with 25 MCU I have both have ATTiny25 20SSU components.
I’m not the best to take macro pictures 
MTN17DDm-NUV :
BLF X6 :
Looks like RMM’s new version has a gate-pull-down and something that could be a flyback diode (?).
When it comes to buying a fully assembled and flashed driver, I’d go with RMM any day, no brainer.
khas’s pictures are at:
MTN17DDm-NUV (above)
BLF X6 (below)
if you can’t see them
Thanks hank, well I can see them, I’m just not sure if that’s a flyback diode I’m seeing.
Thanks Sharpie. There are two diodes on RMM’s driver, right? One for polarity protection and the other one? It’s not a Zener for use with two cells, right?
Thanks again Sharpie. Just to make clear, I’m not asking because I want to copy anything. My only intention was to gain a better understanding of that stuff. But I understand your point, after all everything here is public and it’s Richard’s design.