Hi!
i have a “simple” DD driver which want to work with 2 cells series
what have i to modify to make that happen?
bigger resistor between B+ and “logic” ?
“zener mod” ?
Unless you’re planning on running an MT or 2 3v emitters in series that isn’t possible. A zener mod protects the Mcu from the higher voltage, it does nothing to the output. That requires a buck converter.
Going to increase the voltage to your emitters though, unless your going to rewire.
I’m not by any means good but learning… So I’ll give it a shot :bigsmile:
Looks to me Vcc is pin 6, Pin 3 is GND and it looks like Pin 1 is PWM
So I’d put the 4.3v Zener diode between Pin 3 and GND. I’m not sure if that will work. But according to the blfdd driver that’s how it’s layed out.
EDIT nm Cereal beat me to it… slow
emitters already are 2 XM-L2 in series 
fellfromtree : did you mean pin 5 (top left) and pin3 (top middle) GND ?
If it's 1 cell/2 LEDs in series then you have a boost driver there.
Do we have to file a FOIA request to get all the relevant info here, or what? What light is it? Where are the driver pictures that show the whole thing? Pics of both sides, all of both sides, would be nice, since without that it's too easy to make assumptions that lead you down the wrong path. Very frustrating.
sorry if you are frustrated…
I asked one question and I got the answer - thanks!
since i asked for a 2 cell series conversation of a one cell driver your boost driver idea was too much anyway
but thanks again for your effort!
to complete the story :
I found 3 z diodes on a old network card and put one on the board as fellfromtree directed me.
it worked!
but then I tried to bend it a bit to fit better in the Host - and the Glas broke 
the other two diodes only give me ~ 3 Volts and Light does not work.
known issue of the chip or did I fry it?
What is the controller? What's its voltage range? Does it need to be kept at the original 1-cell voltage to work? Lots of jumping ahead and sideways here.