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I bought this LED driver for my Cree XHP70.2 LED

The driver specs are:

  • Input voltage: DC7V~15V
  • Output voltage:DC6V
  • Current: 4-4.5A
  • Single mode full power

I connected the driver to a power generator that has a current lock, set the max voltage to 15V, and the maximum current to 4.5A. The driver works fine, and it outputs 6V, while the generator supplies a voltage of 7V at 4.5A.

When I connect it to a lipo 4S battery with a voltage of 15V (I checked the voltage with a multimeter), the MOSFET on the driver starts smoking. I replaced the MOSFET, drained the battery to 14V, still the same issue.

Can someone please explain to me what is causing the issue, and how to address it?

Also, if I need a circuit to limit the current for the driver, what's the point of the driver again? Is this driver not rated for such power, or is the product faulty?

EDIT: Talked to the seller and he admitted that the voltage on his store page was incorrect, and came up with a lame excuse why it should be incorrect. Anyway don't buy this product it's junk

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    \$\begingroup\$ Do you have a datasheet for the driver? Aliexpress listings are often poor quality and don't include full documentation. \$\endgroup\$
    – nanofarad
    Commented Oct 3, 2020 at 17:57
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    \$\begingroup\$ 4S LiPo can be over 15V. \$\endgroup\$
    – JRE
    Commented Oct 3, 2020 at 17:58
  • \$\begingroup\$ I did not find a datasheet, and I checked the charge of the battery, it was below 15v \$\endgroup\$
    – Joseph Azzam
    Commented Oct 3, 2020 at 18:06
  • \$\begingroup\$ Can you give the text printed on the driver IC, I will check the datasheet from my Chinese manufacturer and will find the issue \$\endgroup\$
    – Deepak
    Commented Oct 3, 2020 at 19:29
  • \$\begingroup\$ On the PCB you can read "led-130923d" On IC has "4406A gA9N3f" Another IC is a rectifier "ss56" the mosfet is "xorb48" \$\endgroup\$
    – Joseph Azzam
    Commented Oct 3, 2020 at 20:14

1 Answer 1

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You set a current limit on your (I assume) lab power supply (what you called a “power generator”) so to obey the current limit, that set the output voltage to 7 volts. This is what your LED driver worked correctly with.

The way a current limit works is to reduce the voltage until the current drawn by the load is under the limit. By Ohm’s Law, this is they only way to reduce the current.

You then tried to feed it 14-15 volts and it started smoking. Clearly, despite the specs from the seller, it cannot handle that voltage. The same thing would have happened if you raised the current limit on the lab power supply so it was able to put out 15 volts.

You bought a piece of crap. Sorry, that’s how I see it. Either feed less voltage in or buy a better quality driver.

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