have a question about PLCC6 LEDs. All three of them in one housing are white. I want to drive them with the Infineon LED driver BCR402U and a 12V powersupply.
Since one package houses three LEDs, is it ok to put these three LEDs in parallel?
simulate this circuit – Schematic created using CircuitLab
Or should they all be driven by a seperate constant current source. Like this:
What is the likehood that one LED in a single PLCC6 housing fails and kills all other leds?
Thanks!
Either would work. The concerns about parallel led VF issues is unfounded in these applications. The diodes in the same package are so closely matched from the same source process that the difference in their VF is infinitesimal and will not result in any significant change in current through them. This is how many leds are wired in commercial applications.
The third option you have dismissed. You can easily route the 3 diodes of one of these packages in series. The trace would go under it in a z shape. This is how it's done in many commercial applications as well. No vias are needed, easily done in a single layer.
LEDs should not be connected in parallel. Each LED has a slightly different forward voltage (Vf). When wired in parallel they cannot run at their normal Vf and the current will not be equally divided.
Use 3 constant current sources. The easiest way is to use a 3 output CCR.
A good choice for this project would be the Microchip CL320
