| Electronics > Projects, Designs, and Technical Stuff |
| diy 300W LED supply? |
| << < (4/5) > >> |
| mikerj:
Ignoring the problems with isolation, power dissipation and excessive loop gain for the moment, an LED should be driven with a constant current rather than the constant voltage which this circuit provides. |
| rvalente:
Isolation was never a problem to lighting products. HID, fluorescent and even halogens were never isolated (except 12v halogen). |
| rvalente:
You can replace the m2 mosfet with a fast diode, eliminating the sync rectifier and lowering the cost. I believe any 10A 500v mosfet will work here, very common and cheap |
| mikerj:
--- Quote from: rvalente on November 19, 2019, 01:08:36 pm ---Isolation was never a problem to lighting products. HID, fluorescent and even halogens were never isolated (except 12v halogen). --- End quote --- Isolation can definitely be a problem in lighting products if they are either not grounded or double insulated. Commerical drivers for high power LEDs are most always isolated. |
| dmendesf:
Even when the datasheet says that the forward voltage is 37V it's not safe to drive a constant voltage over such a led. This is just an indication about the needed voltage range for your constant current supply. If you drive a constant 37V the device will get hot, so for the same voltage it will demand a higher current (as the temperature coefficient is negative) an will probably enter a thermal runaway until it burns. |
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