# Wiring AMC7135 - Please Help!!!



## PaulH (Nov 6, 2008)

Help!!!

My first attempt at modding, and I'm out of my depth before I've even plugged in the soldering iron.

I've done several searches, but I would be extremely grateful if someone would point me in the right direction.

I have some AMC7135 1.4A boards from DX (as picture below).

From what I have read, I believe the board comes as 350mA. If you solder the bridge to Q1, it would give 700mA, and if you solder the bridges to Q1 and Q3, you get the full 1400mA. Or if you just solder the bridge to Q3, you'll get 1050mA. Does that sound about right, or have I completely misunderstood!

Also, I have marked the +'ve as red, and the -'ve as blue (please tell me if I am wrong!).

Any advice would be most appreciated.

First time inserting an image as well - so I hope this works!!!


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## StefanFS (Nov 6, 2008)

I use a lot of these. There's already a connection on mine so you don't have to solder to get the 1.4A output on those. Unless something has changed, to be certain solder the connections.

Your connections to led + & - are spot on. Batt. + to the center back side and batt. - to the ring around the circumference.

These work best with one big LiION cell (18650 and up), three D-size NiMH 9-10000 mAh or four AA or C NiMH cells.

/Stefan


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## CampingLED (Nov 6, 2008)

:welcome:

Your + and - points are correct. Each IC gives 350 mA and they are wired in parallel, therefore to reduce current you need to remove 1 x IC for each multiple of 350 mA that you want to reduce the current with (remove 1 for 1050 mA, 2 for 700 mA and 3 for 350 mA). 
You can also bridge the two centre diodes if you do not need the reverse polarity protection. The advantage is that the light is still brighter if the battery voltage is lower.


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## PaulH (Nov 6, 2008)

Many thanks for your responses and your welcome to CPF!

So, for the sake of argument, if I unsolder the IC's at Q3 and Q4, then it should give 700mA output?

I wired up a Q5 with the 1400mA arrangement, and although it was a bit brighter than another Q5 driven at 1100mA, I was surprised that the difference wasn't more noticeable. If anything, the 1400mA turned a bit green - if that makes any sense whatsoever!

By the way, I've used a protected 17670 battery in a Solarforce L2 host. I hope no one is going to say :eeksign:.

Thanks again,

Paul


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## StefanFS (Nov 7, 2008)

I forgot: :welcome:

Not quite, if you take Q2 off you get 1050 mA and if you take both Q2 & Q1 you get 700 mA. So it's the other way around.

/Stefan


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## CampingLED (Nov 7, 2008)

StefanFS said:


> I forgot: :welcome:
> 
> Not quite, if you take Q2 off you get 1050 mA and if you take both Q2 & Q1 you get 700 mA. So it's the other way around.
> 
> /Stefan


 
I think we are saying the same thing, just in different words.


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## eatkabab (Jan 10, 2012)

So I'm just trying to string in a single AMC7135 for testing purposes and can't seem to get it to work right. This seemed like the appropriate place to ask. Below you see my semi-ghetto test with an XR-E trying to get it limited to 350ma. It seems I can't get the 7135 to regulate anything. The LED brightness is the same as if I connected the battery directly to the LED.




I followed this diagram:




Didn't use any capacitors because this is just for testing. I'll produce a proper board if I can get this to work.
Any input is HUGELY appreciated. Thank you!


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## yazovyet (Jan 10, 2012)

i'm not sure if it is wise to forgo the cap but lets assume it will work out and...

do you have the 'out' pin of the 7135 connected to the '-' side of the LED (and nothing else)? 
it appears you have the red '+' wire connected to both the Vdd and '+' of the LED, thats good. 
can you use a meter to check and see how much current there is with and without the 7135?


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## eatkabab (Jan 10, 2012)

Yeah the "out" is connected to (-) of LED.
The Vdd is connected to the (+) batt and (+) LED.
GND is connected to (-) batt.

I just whipped up an easier to solder setup and get the same result. It's as if I've directly connected the battery to the LED. I'm gonna insert some .1uF caps to see if it needs it for some reason and then check the current. Be back in a few.


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## eatkabab (Jan 10, 2012)

Having trouble getting the AMC7135 to actually regulate. When wired, it's as if I've connected the batt directly to the LED.




0.1uF cap added

I measured 3.65v at the batt leads, and 3.65v from the GRN pin of the AMC7135 and (+) terminal of the LED. At ~350ma the voltage for that XP-E should be more like 3V...it's also blindingly bright when it should be just semi-blinding bright. I can't get my meter to read Amps. I'm probably doing it wrong but the voltage clearly shows no regulation.

No clue what I'm doing wrong. Please help.



Edit: Since this is a little outside the rest of this thread, I've moved to this one: http://www.candlepowerforums.com/vb...p-appreciated.-Stumped.&p=3844143#post3844143


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