900mA, 30-34v Chazon specs for 30 w cob.
"Technically" one can run a bunch off say a constant current current driver with the required 34 or greater voltage.
They would be wired in parallel.
Current will divide by # of cobs
So a 900mA driver will provide 300mA for 3 parallel cobs .
Soo normally one would go with like a 1500mA driver so each of 3 cobs sees 500mA.
"Practically" there are some issues.
One cobs can be electrically unbalanced and not light uniformly.
Two if one fails open the remaining cobs will share the full current.
1500/2.
There are ways to deal with this. Some more complicated than others.
A simple fuse on each cob would prevent too much current going through the remaining ones
.Current balancing circuits and even dedicated to this task ic's are available.
Bottom line is if you use a 2100 mA driver, 3 fuses at 1A and a driver capable of outputting 34 or greater volts you can run 3 parallel cobs at 700mA each " relatively" safely
Last if one went constant voltage you could use the same parallel cobs, A 36 v power supply with some voltage adjustment to tailor the output to the cob v(f) and a proper resistor with the correct ohms and wattage and run as many cobs as mA are available on the power supply.
Example for 3cibs run at 36v constant and 500mA each.
- each 4.7 ohm resistor dissipates 1175 mW
- the wizard thinks the power dissipated in your resistor is a concern
- together, all resistors dissipate 3525 mW
- together, the diodes dissipate 51000 mW
- total power dissipated by the array is 54525 mW
- the array draws current of 1500 mA from the source
The greater the difference between the power supply and cob v[ f] the worse the efficiency and the more heat on the resistor. Thus the voltage adjustment.
Cob v(f)'s at a specific voltage should be uniform.
Never seen anyone do this though.
There are probably 1/2 doz. real or imagined differences people believe regarding which " blue" to use.
