Buck-Boost 3A Driver at FastTech

Just spotted this new Buck-Boost 3A driver at FastTech. Does it seem good? Wish we had more specs on output from single AA, 2 AA, single Li-Ion, and two Li-Ions. Not understanding the adjustable output voltage - why would you need to adjust output voltage? It is a 5 mode though.

So who is going to test it?


wow, that’s different, isn’t it.

7V max, so I wouldn’t be surprised if 2x18650 would toast it

I’m going to email and ask for 3 mode. if they put that up I’ll be happy to test.

This is adjustable voltage driver. You need to calibrate first what fixed V you want (e.g 4V), then this driver will buck/boost to that voltage. Current will depend on that voltage, minus your emitter Vf and over total circuit resistance, but will be maxed at 3A.

The modes simply will run PWM depending on your initial settings - 100, 30, 5%.

Wow, this looks promising. Looks like we’re getting close to our ideal driver.

With an added Pot, this driver should add some flexibility to our builds. Not quite sure about 2x18650 support though.

Hope the micro controller is programmable. :~

Ideal driver is this: http://www.kaidomain.com/product/details.S020121 :stuck_out_tongue:

Looks nice, but the diameter is 24mm, which won’t fit most lights which have a diameter of 17mm.

Also doesn’t support 1xAA. :stuck_out_tongue:

(Too pricey as well from a budget standpoint.) Thanks for the suggestion though! :wink:

Well, it’s meant for monster lights, which usually have 24mm boards, and don’t run silly AA’s :stuck_out_tongue:

The Fasttech one would be good if it takes 8.4V. As is (7V), it’s just another driver with identity disorder. 7V limit means it’s not suitable for 2x li-ion, no low-voltage protection means single unprotected li-ion will be drained to death, 17mm size is a little too big for AA host (plus there are cheaper options).

I don’t know what this driver is targeted for.

There was a thread about this NJG-18 two years ago:

Thank you, much appreciated. I was wondering if this was new. :wink:

They might mean adjustable output current, which would make more sense. I wonder what max current would be in a mag charger.

It actually has adjustable output voltage.
Maybe this would make a good addition to a driver like the nanjg 105c flashed with lupodrv .
Just use this one to buck/boost to like 4V and let the 105c take care of the current output management.
For me, the 7V upper limit is ok, as i am more interested in single-18650 lights that can also deal with 2xCR123 primaries (for their better performance in the cold) or AAs (for their availability).

When i hook up another driver at the output of this one, i probably should disable the mode-selection on the buck/boost so i don’t feed a PWM signal into the 105c, which means reprogramming/replacing the microcontroller.
From the pictures i can only guess whan kind of MCU is used, seems to start with “12…”, so could be PIC12F629?
Can anyone provide more info on this?

I’m slightly confused about the constant voltage/current setting for this driver.

I’m trying to use a 445nm laser diode with this and it’s forward voltage is about 5.0 volts at 1.8A, which is the max current.

That means I need to set it to 5.0V max, and is there a way to limit the current? A sense resistor perhaps?

I’m seeing a 0.045 Ohm SMD resistor, so that might be it.

For more info about the circuit, Tido’s post here might be helpful, as mentioned by djozz.


Seems like this can power a MT-G2 LED at 3A from a single 18650. Interesting find! (re-find :stuck_out_tongue: )

Well I have a set I had from KaiDomain a few years back. Now, this isn’t a buck driver. It is just a boost driver with adjustable output, so that you can use it to power up 6V Luxeon LEDs or newer EZWhite XML’s if you can find. I tried this one with 2xAa and an XML led, and burnt the driver instantly. Ok, I should have checked the output voltage better, but it is a fragile driver if you are close to VF at your power source. Now I use one with an XPE and 2Xaa light. It is ok this way. But nothing great.

anyone try this yet?

Thinking we may get more run time using this driver and 1 x 18650, vs a modified 105c (zener/resistor mod) and 2 x 18350?

Of course i would prefer 4.5A +, but greater efficiency at 3A is appealing as well

EDIT: Ugh… just noticed its discontinued