Driver Experts, what's this?

This is the driver in a rechargeable floating lantern type torch I have, the led us an xml-t6 but it’s not very bright. Could it be modded?

I see a cat, but iam not an expert.

See it now. I am sure the whole driver could be replaced. What light is this?

Is there enough heatsink to run it hotter without damage?

I can’t get the link from photo bucket working…

It’s probably a discrete component based bjt / FET feedback loop driver.

FET passes current to LED, BJT starts to “turn on” as led current rises which in turn turns off the FET.

Technically one of the resistors should control LED current but from that pic I couldn’t even begin to tell you which one.

My guess: the super cheap BJT is already maxed out (the beefy FET should be OK) and even though the circuit could support higher current the components can’t.

Also note, I used the circuit (bjt/FET) in some of my CC drivers and the power requirements of the “set” resistor (since it’s not actually measuring we can’t call it a sense resistor) are so great even at only ~1A LED current that you have to use a gigantic resistor, I believe the smallest physical size resistor I could find rated at the power I needed was a 1206 and I had to use 2 of them in parallel to get the P rating the math required. In short I highly doubt you’ll get anything more out of that thing, it’s probably already on the verge of burning up now.

This is charging regulator based on LM317 :slight_smile:
Mike

The resistor at r4 is marked 23 so 23ohm? if I bypass this the light gets so much brighter but very hot in seconds… I have a 12 so 12ohm? resistor if I replace the 23 with the 12 and add to the heatsink will it be safe???

As you may have guessed I don’t know much about drivers at all,

Yes. LM 317 is adjustable voltage stabilizer 1.2…37V / 1.5A. It will not be the driver to the LED, but the charging circuit for the internal battery. With such low-powered lamps, there is no driver, only a resistor limiting the maximum current. Or, the LM 317 circuit will be set to some output voltage with current limitation. It would be necessary to know where the individual conductors lead. This is just an estimate.

The wires from the charge port go directly to the battery, then the wires from the circuit board come from the battery to that board then off to the led… If bypassing that resistor makes it brighter surely a lower value resistor in its place will work?

You would need a more detailed photo of the PCB with the components. Not because of the component values, but to see how they are on the board. It is then possible to determine the correct functionality from the wiring diagram. One IO, two transistors, five resistors. Nothing complicated. I suppose the red and black wire leads to the battery, white and black on the LED. It’s just strange that the charging port goes straight to the battery without charging control. The regulation would have to be in the charger, or it is a so-called soft transformer that does not even have a high current in the short circuit. Then charging is limited only by its internal resistance.

Smoked it :person_facepalming: changed the 23 resistor for a 12 and it was very bright then pop a puff of smoke and shes dead something on that board smoked, the battery still charges fine no problems and still powers a 6v mag drop in I have…
Got some 6v 1amp xml drivers on the way from kaidomain to play with hopefully shipping will be fast.

Hopefully shipping will be fast”.. kind of depends on your definition... Are You currently in a coma ? Or plan to be in one in the near future?

There are no suppliers of drivers, led’s etc. In the UK, well not that I can find…

Shipping from KD said 15-25 days to me…

solved :smiley:

Finally got my delivery from KD, and sorted this one out, changed the led from xml-t6 to an xml2-u2 and put in a new 1amp driver. Also added to the heatsheatsink for more thermal mass…