krutzbeuazen
Newly Enlightened
Hello again,
in this topic i asked how to drive 3 LEDs with 3 Dies each, with 20mA and 3.8v each Die.
Since i had no luck finding single ICs for driving them, i decided to use a readily-available driver.
I found a german shop with some tiny step-up-converters, one with constant 630 mA, another one with constant 330 mA.
My LEDs have 4 pins each, meaning i can wire up every Die individually.
Since it´ll be several Dies, i´d like to use limiting resistors, to prevent thermal runaway.
My question:
what would be a smart way to build it all together?
should i use a resistor for each Die, or is one resistor for one LED (with 3 Dies on one piece of metal) enough?
What are reasonable values for resistors in a constant-current-setup?
if necessary, i´ll buy some more of these LEDs, instead of wasting half of the energy in resistors. it shouldnt be too many LEDs though, since they are at 17$ each, and should fit into a tiny flashlight.
i saw minimags with 5 LEDs in them.
nicer would be a single cr123 flashlight, but have no idea where to get one (in germany).
if someone could perhaps calculate it out for me, like "use 10R for three Dies in parallel, use 5 LEDs, with the 330mA circuit", i would be very grateful!
Thanks in advance for any hints and ideas!
manuel
in this topic i asked how to drive 3 LEDs with 3 Dies each, with 20mA and 3.8v each Die.
Since i had no luck finding single ICs for driving them, i decided to use a readily-available driver.
I found a german shop with some tiny step-up-converters, one with constant 630 mA, another one with constant 330 mA.
My LEDs have 4 pins each, meaning i can wire up every Die individually.
Since it´ll be several Dies, i´d like to use limiting resistors, to prevent thermal runaway.
My question:
what would be a smart way to build it all together?
should i use a resistor for each Die, or is one resistor for one LED (with 3 Dies on one piece of metal) enough?
What are reasonable values for resistors in a constant-current-setup?
if necessary, i´ll buy some more of these LEDs, instead of wasting half of the energy in resistors. it shouldnt be too many LEDs though, since they are at 17$ each, and should fit into a tiny flashlight.
i saw minimags with 5 LEDs in them.
nicer would be a single cr123 flashlight, but have no idea where to get one (in germany).
if someone could perhaps calculate it out for me, like "use 10R for three Dies in parallel, use 5 LEDs, with the 330mA circuit", i would be very grateful!
Thanks in advance for any hints and ideas!
manuel
