Hi, I've been doing a lot of research for powering LEDs under varying voltage conditions more specifically about 10-18volts.
So far I bought twelve Lumileds amber superflux Model# HPWT-ML00, I've decided to do a 4x3 array, (4 parallel strings with 3 LEDs each string).
From what I understand in the datasheet the LEDs should be runned at 50mA-70mA with a nominal forward voltage of 2.6v @70mA.
I've seen five different ways to power the LEDs, what is the most reliable way out of the five?
1) Using a current limiting resistor in each string.
3) A circuit that uses an NPN transistor, a N-channel FET, and 2 resistors.
2) Using a LM317 regulator with a resistor between the adj and out to make it a constant current.
4) A sense pass current regulator.
5) The switching type current regulator.
I'm also curious about protection circuits, which is a silicon diode in series with the LEDs, and a zener diode wired in parallel, is this nessesary and/or helpful?
Here's some example diagrams of the above circuits.
Resistors with protection diodes
**broken link removed**
transistor circuit
**broken link removed**
lm317 regulator
**broken link removed**
switching and sense pass circuit
**broken link removed**
So far I bought twelve Lumileds amber superflux Model# HPWT-ML00, I've decided to do a 4x3 array, (4 parallel strings with 3 LEDs each string).
From what I understand in the datasheet the LEDs should be runned at 50mA-70mA with a nominal forward voltage of 2.6v @70mA.
I've seen five different ways to power the LEDs, what is the most reliable way out of the five?
1) Using a current limiting resistor in each string.
3) A circuit that uses an NPN transistor, a N-channel FET, and 2 resistors.
2) Using a LM317 regulator with a resistor between the adj and out to make it a constant current.
4) A sense pass current regulator.
5) The switching type current regulator.
I'm also curious about protection circuits, which is a silicon diode in series with the LEDs, and a zener diode wired in parallel, is this nessesary and/or helpful?
Here's some example diagrams of the above circuits.
Resistors with protection diodes
**broken link removed**
transistor circuit
**broken link removed**
lm317 regulator
**broken link removed**
switching and sense pass circuit
**broken link removed**