since the HPSC4 behaves better when the load is balanced

What is "behaves better"?
How does it behave worse if they are not balanced?

 

I think suitable value resistors should work unless you need to adjust the current after it's value is initially chosen.
I don't understand why there is interaction between the channels.
Les.

That's fair enough, but unfortunately the current may change during operation to adjust the brightness of the LEDs, since the strobe/capture speed is fixed. I would love to know why there is interaction as well, support mentioned it was an operational safety and stability measure, which I can understand since the HPSC4 may drive all channels at once at very high current so I can imagine that having voltage somewhat balanced induces less load to provide very different voltages ? This will likely remain a mystery unfortunately...

 

What is "behaves better"?
How does it behave worse if they are not balanced?

It becomes harder to set higher current for all channels at once in continuous mode, which is a corner case but still should be avoided. For example, it may allow lower current to the short string compared to the other ones, even though it can handle it. I wish I could know exactly what is going on but it is a black box until someone smarter than me can reverse engineer it...

 

Do you need to control the strings separately? If not, why can’t you just balance the strings?

 

Do you need to control the strings separately? If not, why can’t you just balance the strings?

The strings are already controlled individually by the HPSC4 which acts as 4 constant current drivers and they need to be controlled separately. Space is very limited so I can not fit more LEDs in the cavity where they are installed, and I could of course add more outside, but that seems like a waste and could lead to undesireable stray light if not taken care of properly. My initial thought was to use diodes to drop voltage as I do not want to put a hard limit on the current that can go through the strings but there might surely be something better out there

 

If you don’t need to turn them and off separately, what is the reason for putting 4 in one string and 14 in another?

 

The driver needs to strobe the 4 strings at different times to capture objects with different light setups as they pass in front of a camera. The difference in numbers of LEDs is due to having to fit them on a very small area, and balancing the power needed from each source.

 

Okay, I misread your last answer, inserting a not. I understand now.

 

Okay, I misread your last answer, inserting a not. I understand now.

No worries, thanks for sticking around