7135 Circuit Problem

Hmmm

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I'm trying to use a AMC7135 powered by 4S lifepo4 to drive an XML EasyWhite 12v led but it isn't working. Less than 1ma is going to the led.
 

yazovyet

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amc 7135s have a maximum voltage input of 6 volts. unless you have something to deal with this (such as 3 amcs in SERIES) then i'd expect the AMC is dead.
 

AnAppleSnail

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I'm trying to use a AMC7135 powered by 4S lifepo4 to drive an XML EasyWhite 12v led but it isn't working. Less than 1ma is going to the led.

Connect the DriverOut to an appropriate resistor... say, (V=IR, 12v = 1A * R, 12 ohm 12 watt) and see what happens to check the driver.
Connect the LifePO4 to the XML EasyWhite with a decent resistor to check the batteries, LED, and voltage.
 

Hmmm

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the amc7135 is not dead. it still works powering a "normal" xml off a 18650 battery.the leds are fine. I tested them before with a linear regulator but it needed toomuch voltage overhead. I was hoping to use the 7135 for its low voltage overhead.
 

AnAppleSnail

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the amc7135 is not dead. it still works powering a "normal" xml off a 18650 battery.the leds are fine. I tested them before with a linear regulator but it needed toomuch voltage overhead. I was hoping to use the 7135 for its low voltage overhead.

LiFePO4 OC voltage is only 3.3v freshly charged, giving you 0 to 0.9v headroom. Not quite enough.
 

yazovyet

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I'v been wonding 2 things:
1) Are you useing an amc7135 based driver or a bare chip? Do you have any information about it from where you bought it?
2) What gave you the idea that this would work?
 

Hmmm

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The led starts turning on around 11.3 volts for me and is running at 1 amp at 11.7 volts. They are bare chips that i etched a board for. I ordered them from ebay.

I don't know why it woudln't work I guess. I assumed that the 6v limit was due to the v-drop of normal leds, making so if you sed over that it would get to hot with 1v drop i don't think i would have too many problems.
 
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kramer5150

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What driver circuit are you using? If its just our standard garden variety 7135 driver board with 7135 chips configured parallel, your 4S cells are exceeding the Vin for the circuit.
 
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