What is the difference between these ?
They all come in single channel, 350mA, no PWM control, SOT-89 package and 2.7 - 6V supply (A705 goes up to 12V)
Interesting, the datasheet says that the A705 is compatible with the AMC7135.
With the higher voltage range, I wonder if it’s ideal for driving MT-G2 led’s without much hassle?
It’d take care of 1/2 of the problem. The MCU would still the lower voltage.
That’s true… maybe a resistor to drop the voltage to the Attiny13A?
Sounds like this might open up some interesting possibilities. Waiting for our driver experts to weigh in.
Anyone know where I can get some A705’s? I have searched with no luck.
Any 7135 used with a 6v LED and 8.4v input voltage only has to deal with the ~2v difference between input and Vf (in operation, Vf is higher than 6.000v and input voltage sags).
MCU voltage is a simple fix with a 4.3v Zener diode between pin#8 and ground, and a 200 ohm resistor in place of the polarity protection diode (the voltage supply point in the circuit for the MCU) to limit the current leaking away through the Zener.
edit: Exact same setup works with 2x XMLs in series with 2 cells, or 3x XMLs in series with 3 cells.
I would like to try the AMC7123 20-60-120ma single output msop8 pkg. Here is the link to the ADDtek driver page
Anyone tried any of these yet ?
Nope. Anyone find a low quantity/price supplier?
There’s 4 on alibaba last time I checked that supply from 1 to 10 as a minimum by memory.
So you’re saying 7135s are happy running at over 12v input? Have you tested this?
What is the input voltage limit for 7135s anyway? I thought I saw 6v in the datasheet and that we were already pushing beyond the limits running them on 2S.
I’m not talking about the amount of energy they can burn off, simply interested in what the operating voltage limit is.
Cheers
Difference between input and Vf is all they know about, they have no connection to the positive side of the battery. At no point in the circuit is the full input applied across any pins anywhere on the 7135s. LED-, and GND, only. The PWM control applied to the Vdd pin is a different story, the MCU must be at 6v or less, as the MCU does have both + and - connections to the input v, and if that is handled in one way or another, the voltage output to the 7135's Vdd will be in the sub-6v safe range also. But the current-carrying part of the 7135, it can't be affected by the total input voltage because they have no connection across it.
This is the same thing I said above so something about the way I'm explaining it must not be clear enough, tell me how you think it works and I'll try to spot the part where you're going astray. :)
Damn of course you’re right, I didn’t make the connection that they are not actually “seeing” the LED+ side of the circuit at all and only operating on the PWM signal from the MCU.
Got it, sorry for the brain fart and thanks for the great re-explanation 
lol :beer:
Now... if you get up to a large number of (~3v) LEDs all in series and the same number of cells all in series, the cumulative spread between input & Vf can get out of hand. But there are workarounds like a series-parallel array instead of all one or all the other.
1x 3.3v LED with 1x 4.2v cell = 0.9v difference (let's not worry about voltage sag, or higher Vf with higher drive currents for now, this is just the back of the envelope version, which is all I'm qualified to do anyway)
3x 3.3v LEDs with 3x 4.2v cells = 2.7v = sure, go for it
6x 3.3v LEDs with 6x 4.2v cells = 5.4v = maybe... depends on how many 7135's there are to share the heat load
18x 3.3v LEDs with 18x 4.2v cells = 16.2v = fire! fire!
I saw that, …. just wish there was a trusted storefront for this stuff. I get spammed weekly from a broker that supplied a AMC7135 quote (thrice the price of FT) nearly a year ago, even with all the alibaba email controls turned off.
A couple of the alibaba sellers have their own websites.
Maybe they’re worth contacting ?