At this moment I'm working on a project that includes driving multiple LED interfaces. I've got 16 LED interfaces in total, each interface has two 5V inputs. One input for the high current LED drivers and one input for the digital logic. I kept the logic and load supplies separated due to the fluctuating current consumption from the LED drivers (TLC5940). The interfaces have a common ground, however I designed them so the LED driver grounds and logic ground are only joined together at a single point at the power connector. All the other LED driver and logic ground areas are separated from each other. The LED drivers from each LED interface are drawing about 1A each.
Now I'm not certain about how I should supply all those interfaces. Currently I'm thinking about this. I have four interfaces that are grouped together (so I have 4 groups) that I call 'units'. All the high current LED drivers from each unit are fed by a single regulated 5V/7A supply. All the logic sides of the LED units are fed by a single 5V/10A supply. See the image for a reference. Can anyone tell me if this setup (including the separation of the high current LED drivers and the logic components) is a good idea? Am I avoiding high current ground loops with this setup? If someone has any tips or tricks I love to hear them! Thanks for all your time!
In the image the left side of a unit are the high current LED drivers, ground separated from the logic components at the right side. Both grounds meet at the common power supply ground pin from the interface. The most right PSU is feeding all the logic components. Both the LED drivers and logic components are fed by a 5V PSU.
EDIT: So as @Dave mentioned in the comments the design in the first image isn't a good solution at all. My first design looked something like in the image below. If I'm correct I won't have any ground loops between the interfaces/main processor unit as the grounds are joined together at the power supply (I can call this star grounding, right?). With this setup I'm only concerned about the (possible) voltage drops on the 5V rail. Because the load can vary quite a lot, e.g. if all the LEDs switch on the current demand is increased with roughly 16A. Of course I decoupled the TLC5940's from each interface with some large capacitors. Besides that I forgot to mention that the logic is fed by a 3V3 (LDO) regulator which is connected to the 5V rail of the led interface. However I'm still concerned with the possible voltage drops on the 5V rail when the LED interfaces are driving all the LEDs. In practice would a setup like this with a large single switching power supply work? Or am I asking for trouble with this kind of setup? Thanks for the input!