Looking for LSH regulation board schematic.......

Does anybody know where I may acquire the schematic diagram of an Arc LSH-S regulation board?

I have a modded LSH bezel with a TW0H Luxeon III using the stock regulation board adjusted for a 611mA current. The current at the batteries is 660mA. The light is not running in regulation. An electrical engineer friend of mine would like to see a schematic of the board, to determine what can be done to it to get it to run in regulation. I am using two 2,300mAH NexCell NiMH AA batteries in the Arc AA battery tube, and apparently the 2.4 battery voltage is not enough to have the emitter run in regulation. The board was really made for a Luxeon I with a 350mA current draw, using a 123 battery. With the schematic, my friend will be able to modify the board to allow regulated operation.

Re: Looking for LSH regulation board schematic...

I'm no expert on the CIRCUIT in the LSH, even though I've modded a bunch of 'em, but maybe you should contact Peter Gransee or perhaps even fellow CPFer cy about the availability of a schematic. Now that ARC the company has unfortunately left us, it shouldn't be that big a deal to share the schematic, I wouldn't think.

One other thought... I vaguely remember someone talking about replacing the stock diode in the LSH circuit with something offering lower voltage drop. This would have the effect of getting a higher voltage to the rest of the circuit, and might give you just enough of a bump upward voltagewise to put the LSH circuit in regulation on those 2AA NiMH.

In the worst case, you could always try 3AA NiMH with the Arc LSH! I think it would work fine, but that would be one heck of a long battery tube!
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Re: Looking for LSH regulation board schematic...

I'm no EE (but your friend is). Couldn't your friend draw the schematic by looking at the board and it's components?

Re: Looking for LSH regulation board schematic...

The only thing your EE friend need to know is the part number of the magic chip marked LTNH. It's Linear Technology LT1618. I think he should be able to work out everything, it's no multilayer circuit board shouldn't be hard for him.

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luxlover said:
Does anybody know where I may acquire the schematic diagram of an Arc LSH-S regulation board?

I have a modded LSH bezel with a TW0H Luxeon III using the stock regulation board adjusted for a 611mA current. The current at the batteries is 660mA. The light is not running in regulation. An electrical engineer friend of mine would like to see a schematic of the board, to determine what can be done to it to get it to run in regulation. I am using two 2,300mAH NexCell NiMH AA batteries in the Arc AA battery tube, and apparently the 2.4 battery voltage is not enough to have the emitter run in regulation. The board was really made for a Luxeon I with a 350mA current draw, using a 123 battery. With the schematic, my friend will be able to modify the board to allow regulated operation.

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Datasheet Link

Luxeon specific application notes

Isn't the LS board basically a previous generation BB. If so, then all the shoppe's sandwiches should be having problems running in regulation when used in minimags, shouldn't they?

Re: Looking for LSH regulation board schematic...

660 is at the edge of operation for that IC. It may very well not reach regulation. At that drive level and with a high Vf LED the IC could require more than 1.5A on the input which is where the IC limits.

Somehow tho there seems to something else wrong. Since you say the input is around 660. that sounds like only one of the two sense resistors is in setting the output current to ~400mA drive or so.

I'd double check you sense resistors and verify they are the correct value and are soldered on properly.

Re: Looking for LSH regulation board schematic...

milkyspit,
Very funny on the "baseball bat length" of an Arc body with 3xAA batteries!! That would no longer be a light, but rather a "lethal weapon!"

greenLED,
I am hoping that my Filipino buddy Billson will be willing to digitally capture both sides of his Arc LSH's regulation board, and email me those images.

koala,
Yes, the images will tell Joe the part number of the converter chip.

Newbie,
Great links. I have already sent them to Joe the E.E.

Billson,
Good question comparing the sandwich used in a minimag to the board used in the LSH.

dat2zip,
Lucky me that 660mA is "on the edge?" If I told you that my LSH ran for 1 1/2 hours before flickering, then shut itself off, then turned itself on, and then ran another 6 hours before becoming "unusable", would that have any impact on your "sense resistor" idea? If not, I will speak to LitFuse about this. P.S: You have a PM waiting for you.