3.2 volt, 350mA LED Golden Dragon LCW W5SM
Forward voltage
min, Typical, max
2.5 volts, 3.0 volts, 3.5 volts = 150mA
2.6 volts, 3.1 volts, 3.6 volts = 225mA
2.7 volts, 3.2 volts, 3.7 volts = 350mA ******
2.8 volts, 3.3 volts, 3.8 volts = 500mA
2.9 volts, 3.4 volts, 3.9 volts = 650mA
3.0 volts, 3.5 volts, 4.0 volts = 800mA
This is at 25 C.
At -25C add 0.2 volts
At 0C add 0.1 volts
At 25C add 0 volts
At 50C subtract 0.1 volt
At 80C subtract 0.2 volts
At 120C subtract 0.3 volts
Do not drive any LED with constant voltage (even the 20mA LEDs).
In this case, you could use 4 LEDs to make a "12 volt LED".
If the voltage drops 0.8 volts the current (and light) will be 1/2!
If the voltage rises +0.8 volts the current and light will be 2X and will burn out! (This is +/-0.2 volts/LED.) This is at 25C and your part will heat causing a 2X larger change.
Look at the TPS61160 from TI.COM to see a constant current application.