I have a display assembly with 8 WLEDs in 4s2p configuration for backlight. However, the split between 2 strings is made within the display assembly so I have only a single anode/cathode pair in the display connector. Each WLED has a Vf of 3.2V and If of 20mA, so I need to source 12.8V @ 40mA to drive the LEDs. In my current design I have been using a TPS61165, which has been working great.
Now for the next iteration of the device in question, I want to make use of the Qualcomm PMI8994 PMIC which comes with the SoC module we have selected. It has an integrated WLED SMPS that is capable to supply the required voltage, but has 3 WLED sink drivers, which, judging by the datasheet, can sink max 30mA each.
Assuming I synchronously control each sink driver to set brightness, can I safely split the backlight cathode connection on my PCB and connect them to 2 of the LED sink drivers to get under the 30mA limit?
Note that the part within the dashed region is something I can't change.