First of all, I have read many articles about the non-linear effects of voltage vs current of LEDs. I also know that current will rise as temperature rises, batteries have resistance, LEDs brightness is not linear. All in all, LEDs are finicky devices.
But lets say we have a 100% perfect scenario:
- The LED is rated for 9v at 700mA. The temperature somehow stays a constant 25C
- The power source, never mind what, is DC 1000000 volts and can output 1000000 amperes. The voltage remains constant no matter what the load is, i.e. 0 resistance.
- We have a switching voltage regulator that somehow handles all the power and is 100% efficient with 0 ripple, etc.
If I have a CC/CV setup with the output at 9v and current limited to 700mAh. The LED should now be at full brightness.
Let's say that I want to dim the LED by keeping the voltage output at 9v and reducing the current to 350mA.
- This would dim the LED right? Theoretically, 1/2x the CURRENT = 1/2x the brightness (Ignoring the fact that our eyes are non-linear and that the voltage stays at 9v)
- Is there anything wrong with doing this? Will I damage the LED by forcing 9v through it and allowing it only 350mAh?
- Is it really better to do keep current limiting at 700mA but reduce the voltage? This would result in the current used by the LED plummeting if I reduce the voltage a teensy bit
Now let's say I want to put the brightness back up to 100%. Assuming I reduced the current limiting to 350mA before and kept the voltage at 9v, I would now have to increase the current limit back up to 700mA
- Alas! I accidentally increased the current limit to 200 Amperes! (but kept the voltage at 9v)
- This shouldn't do anything, should it? The perfect LED simply draws 700mA at 9v (because current is simply drawn, it generally cannot be forced?)
If I reduced voltage before, yet kept the current limiter at 700mA, I would then have to increase the voltage. (keeping the current limiter at 700mA) - Oopsie! I accidentally increased the voltage to 15V. Now this is far beyond the overvolt acceptance for LEDs, The current would try to skyrocket, but it is being limited to 700mA. - Is there any detrimental impact on having the LED run at 15v 700mA? Any normal unregulated LED would have surely burnt itself up by now.
So here are the scenarios for the LEDs in a nutshell:
350mA @ 9v
500mA @ 7v
700mA @ 9V
700mA @ 15V
Would doing any of the above destroy the LED necessarily? Except for that 4th one.
It is not possible for me to use PWM to control the brightness of the LEDs
Sorry for exaggerating everything, I just wanted to make things crystal clear. Is anybody able to brighten me up on this topic? Thank you