Can anyone please help me how can i make amc7135 chip output 150ma without using attiny13a. I gave my grandfather s2+ with only one 7135, I removed the attiny13a and two 7135 , so the output is 350ma one mode, but for him it is too bright. So maybe if i can make 7135 output 150ma only it will satisfy him but i know that i can only achieve 150ma if i have programmed attiny13a but i don’t know how to program. Or maybe there is a chip like 7135 that has only 150ma output?
AMC7135 IS 150mA only (there are versions that are 180mA also but they are not that common).
1 x AMC = ~150mA
2 x AMC = ~300mA
3 x AMC = ~450mA
etc…
if you want less than 150mA then you need MCU or higher value resistor depending on the driver tipe…
my bad, don’t sleep and read BLF at the same time :bigsmile:
:~ ???
Crap, it’s too early to think straight, my bad, it’s actually 350mA and 380mA
maybe you could use just a resistor instead? or maybe he could use an incandescent flashlight instead 
:bigsmile:
or maybe you could change driver to something without memory, that always starts in low?
otherwise i think there’s people who would be willing to flash a driver with only low mode, and send it to you if you know how to change the driver.
Even at 150mA it would be bright for old people I gifted many with single 7135 they all say it is bright and led hurts their eyes. I think what you need is a diffuser lens, dc fix or something like that.
Another option is to have RMM program a 7135 for single mode 100/255 and solder that attiny13A onto the board.
What if i put a resistor in series to the 7135 output will that put out less current? I don’t what value of resistor to put.
Only if the resistor is large enough to push the 7135 out of regulation, which defeats the purpose of the 7135.
You can try a 10 ohm resistor just by itself. A fully charged cell will give you ~145 mA into an XM-L2. With the cell down to 3.4 V (typically not much charge left beyond 3.4 V anyway) it should still give ~75 mA. Not great regulation, but simple enough to try. Resistor will dissipate ~200 mW with a full cell and should be rated for 1/4 W or larger, preferably 1/2 W.
Note that without a MCU the light will not have low voltage protection and you should use protected cells in case the light is forgot on.
I think the resistor would best go in parallel with the emitter and not in series. The value would be set to draw 200mA from the voltage at the emitter operating at 150mA. I found a graph that shows an XM-L2 operates at about 2.7 volts at 150mA. At 2.7 volts a 13.5 ohm resistor would draw 200mA away from the emitter at 0.54 Watts.
Someone should check my math and logic 
I claim if you know the voltage across the emitter when operating at your desired current (150mA) then you can use Ohm’s law to determine the resistance that will draw the remaining current (200mA) at that voltage.
E = I * R so 2.7 Volts / 0.2 Amps = 13.5 Ohms
P = I * I * R == 0.2 * 0.2 * 13.5 = 0.54 Watts (at least)
Note, there are likely better ways to do this — since this will waste a good deal of power.
[EDIT] DEL’s suggestion (a 10 Ohm resistor) is drop dead simple and won’t waste as much power. IMO, the lack of regulation is almost a non issue with regard to output.
Parallel won’t work. You will still get high current through the emitter in addition to the current through the resistor. Either a throttled down 7135 using pwm or just a plain resistor in series.
“You will still get high current …”
Why? The 7135 regulates the current at 350mA. We know that with multiple parallel emitters the current is divided among them accordingly. How is this different?
I suggest either replacing the reflector with a frosted wide-angle TIR or replace the clear glass lens with a frosted lens. That will turn the S2+ into a flooder which should be less “intense.”
My apologies, it was unclear you were using a 7135 and the resistor as a current shunt. Still, it seems an inefficient way to do the job if you are feeding 150mA to the LED and bleeding off 200mA through the resistor.
There are also chips that use a resistor to set output current. This one goes from .5mA up to 500mA. So does the Lm713
I tried the 10 ohm resistor in series and i got 0.14A with 4.15v and at 3.1v it gives 0.05A. I hope he will like the brightness at that range. Thanks for all your help.
Try a layer wax paper over the lens. For greater effect double it. Poor mans cheap diffuser.
+1 on adding a diffusion film on the lens, instead of altering the 7135. Also ask your grandfather if the cool white light bothers him. You could replace it with a warm white LED so it resembles incandescent that can be easier on the eyes.
These are a nice warm white:
These are also a bit warmer than the above, but you have to reflow them onto a board:
Would it be possible to make up a spacer / carrier for a AA battery to adapt it to the 18650 size and see how that works?