I had run a 3v xhp50.2 in my UF-20 host with the 17mm (old fet driver that doesn’t have Biscotti) and it runs great! Single Vapcell VTC6 rewrap and it’s crazy bright. That driver will do 6+ A on a fresh high drain cell, more than the new version driver with Biscotti. Yes, the UI isn’t as easy to master as Biscotti but I’ll take power over function sometimes!
Solder some additional proper value sense resistor in parallel with the stock one, and have both Biscotti and (PWM free) regulation. Problem solved, Sirstinky.
Hmm so I can make the output as good as the older one? How do I do that? What resistor do I need to add? If it’s easy I might take that nlon since I like Biscotti quite a bit over that other UI. Thanks
Where is this driver? I can’t find it on the Convoy store
I believe it is the 4 mode driver 0.1, 3, 30, 100%, but have to you ask for biscotti when you order it.
Okay, I’ll message Simon and inquire. It would be perfect for the Osram whit flat on my hunting light, 100% only
As EasyB says, the newer linear driver which can now be ordered with Biscotti is the ∅17mm SST-40 5A. The ∅20mm 6A and ∅22mm 6A SST-40 drivers will also be available with Biscotti, as Simon said here.
On the topic of raising the maximum output current for these drivers, and answering Sirstinky's question, since the drivers are regulated it must be noted that each driver mode implies a proportional voltage drop at the current sense resistor. Given that the ∅17mm 5A driver uses a 10 mΩ sense resistor (along with the ∅20 and ∅22 mm versions), we can calculate the driver's sense voltage(s). For the highest mode, 5 A, V = I × R = 5 A × 10 mΩ = 50 mV. So, the driver allows up to 50 mV of drop in its sense resistor (not verified by me yet), with proportionally less sense voltage in the lower modes.
I made a search in AliExpress for 1210 “sense” resistors of adequately low value, found 3 advertisements worth mentioning. From cheapest to most expensive as I see them, including shipping and handling:
- https://www.aliexpress.com/item/4000052318048.html Chinese Super Electronic market.
- https://www.aliexpress.com/item/32947351635.html Longqi store.
- https://www.aliexpress.com/item/644897575.html C&G Semiconductor.
All of them sell values which matter here. A few examples for 50 mV sense voltage:
- A 56 mΩ (R033) resistor adds I = 50 mV / 56 mΩ = 0.893 A (0.892̅8̅5̅7̅1̅4̅).
- A 33 mΩ (R033) resistor adds I = 50 mV / 33 mΩ = 1.515 A (1.5̅1̅).
- A 30 mΩ (R030) resistor adds I = 50 mV / 30 mΩ = 1.667 A (1.6̅).
- A 22 mΩ (R022) resistor adds I = 50 mV / 22 mΩ = 2.273 A (2.2̅7̅).
- A 20 mΩ (R020) resistor adds I = 50 mV / 20 mΩ = 2.5 A.
All of them can be combined in parallel. And bear in mind that while this increases the maximum possible output, remember that you will only reach it for as long as there's enough voltage difference headroom between the input from the loaded battery and the emitter Vf at that current, after spring and contact losses and etc. You also may not want to raise the maximum current excessively, as it will affect the remaining modes proportionally. After adding an R020 in parallel with the stock R010, for example, the 30% mode will raise to 2.25 A and 3% mode to 0.225 A.
At last I'll just add that, if you remove the onboard negative thermal coefficient resistor used for temperature control, please make sure you reinforce driver cooling as much as possible, and take proper care.
Tue, 03/31/2020 - 02:06
sorry ,no plan ,because beam spot of sst40 is more even than xhp50.2
In contrast, I recommend sst40
:+1: :+1: :+1:
Simon, will the new 22mm boost driver with Biscotti also be availible in 20mm?
Hi Simon and everyone!
My M21C review is out now:
I don’t quite understand, which driver are you talking about specifically?
In addition, you want 20mm size?
Thanks
I think he means the 17/22mm SST40 driver that we can ask for Biscotti on - if that’s going to be made available in 20mm format.
Is that just an Attiny13 on it? Maybe I should have grabbed those instead of the 6A CC drivers 
If the 22mm boost driver with Biscotti UI which you supposedly use for the M21C/M26C with XHP70.2 leds will be also abailible in 20mm size.
If someone else have received that new biscotti driver. I have current 17mm version with 4 modes and will be interesting if we can just upgrade it the firmware. I supposed that biscotti firmware is ported to another micro different from Attiny series.
What chip is on that board? Care to take some good photos that show the MCU?
Ok I will made some close up pictures with my Andonstar micro and will post them soon. But I think marks on micro and transistors was laser trimmed. Also from Convoy store listing we can see markings of transistors but the MCU is it without it. Also it have 10 pins compared to 8 pins of Attiny so the Biscotti firmware is most likely ported to another MCU family.
I got mine and yes, the markings on the mcu and mosfet are removed.
oh ,sorry ,20mm is small
Sorry,As a trade secret, the driver manufacturer does not want to disclose the model name.