For my circuit, I want to use 110VAC mains power, via a TRIAC dimmer to an LED Driver power supply.
For this use case, I am confused on whether to use a constant voltage AC to DC LED driver power supply, or a constant current AC to DC LED driver power supply.
When would I use one vs the other? Which supporting components would I need to drive the LED array?
I thought that if I used a constant voltage supply, using the formula R = (Vs – Vf) / I, I would simply put a resistor in series (calculated by the above formula) to be sure "I" (current) never exceeded the LED array's maximum forward current.
For the constant current power supply, would I calculate the minimal value resistor that when I was at Vmin of the LED power supply, it would translate to a current just below whats needed to light up the LEDs, and when its at Vmax of the LED power supply, well, thats the maximum current I would have at my disposal to light up my array? (So in this case, I would need to find the power supply with the ideal Vmin and Vmax to take advantage of the LEDs' power capacity?)
Let me know if I'm on the right track here, or if I am missing anything… thank you.
Best Answer
Sorry, Geremy, but you've misunderstood. The module you're looking at will simply not work well with the dimmer turned down. It will ALWAYS try to drive 1400 mA through your LEDs. If the input voltage is too low (because of your dimmer) it will get very unhappy and may do strange things.
The 17 to 29 volt range just means that it will successfully drive 1400 mA through an LED string when the voltage needed to produce that current varies between 17 and 29 volts. This voltage difference could be produced by differing numbers of LEDs in a string, or using the same number of LEDs, but of different colors.