Hi there,
I want to drive LEDs
8x1W LED (350mA, 3,5 - 4 V)
4x2,5W LED (700mA, 3,5 - 4 V)
I dont have bought the power supply for it yet, cause I dont know which one would be best cause of the method of construction...
Would be best to put them into three rails?
1.Rail 4x1W
2.Rail 4x1W
3.Rail 4x2,5W
Would be best to drive them via LM317 via constant curent?
If yes, how would i do that? And the limitations of it? I looked in datasheet, dropoff 3V, 1,5A. What does it mean? how many LEDs can I drive via single LM317? only 1,5A/,35A? or depends on power supply voltage???
for example if I had 18V, 1,7A, 30W power supply, how many 1W LEDs and how many 2,5W LEDs can I drive via single LM317...? how is the formula for calculate that?
((18V-3V)/3,75V) / per rail = 4LEDs consume 350mA (1rail)
1,5A/,35 = 4 rails of 4 LEDs?
i am sure i am wrong
HELP
Or to buy 15V, 1,6A, 25W power supply. Will the voltage split and power all four LEDs (350mA) equally per rail if I put them in rail without any resistor, or LM317...? What will be their Voltages? 3,75 each? and the curent flow them 4/3,75*350mA?
All the power supplies I mentioned are stabilized
Thanks in advice
**broken link removed**
I want to drive LEDs
8x1W LED (350mA, 3,5 - 4 V)
4x2,5W LED (700mA, 3,5 - 4 V)
I dont have bought the power supply for it yet, cause I dont know which one would be best cause of the method of construction...
Would be best to put them into three rails?
1.Rail 4x1W
2.Rail 4x1W
3.Rail 4x2,5W
Would be best to drive them via LM317 via constant curent?
If yes, how would i do that? And the limitations of it? I looked in datasheet, dropoff 3V, 1,5A. What does it mean? how many LEDs can I drive via single LM317? only 1,5A/,35A? or depends on power supply voltage???
for example if I had 18V, 1,7A, 30W power supply, how many 1W LEDs and how many 2,5W LEDs can I drive via single LM317...? how is the formula for calculate that?
((18V-3V)/3,75V) / per rail = 4LEDs consume 350mA (1rail)
1,5A/,35 = 4 rails of 4 LEDs?
i am sure i am wrong
HELP
Or to buy 15V, 1,6A, 25W power supply. Will the voltage split and power all four LEDs (350mA) equally per rail if I put them in rail without any resistor, or LM317...? What will be their Voltages? 3,75 each? and the curent flow them 4/3,75*350mA?
All the power supplies I mentioned are stabilized
Thanks in advice
**broken link removed**
Last edited: