20 volt 2 amp drop that's 40 watts
This is a switching mode regulator.
There's onboard thermal regulation which prevents anything excess current being delivered to the LED.
That doesn't mean the less-than-excessive voltage from the regulator wouldn't cause excessive current / power dissipation on the led.
No, the board does not regulate current output at all: they call it a voltage regulator for a reason.
Read the data sheet it said if the output is shorted the chip decreases the voltage
you saying ohm 's law don't apply dherry if the voltage goes down the current can't go up.
20 volt 1 ohm load 20amps 5 volt 1 ohm load 5 amps
Now whats this say
(3) The oscillator frequency reduces to approximately 18 kHz in the event of an output short or an overload which causes the regulated
output voltage to drop approximately 40% from the nominal output voltage. This self protection feature lowers the average power
dissipation of the IC by lowering the minimum duty cycle from 5% down to approximately 2%.