Grounding of multiple SMPS's

[eem2am]

Hello,

We have a PCB , 26mm x 45mm (double-sided).
(This area does not include the offline flyback at the front end, because this question does not concern that part)

The secondary side of the PCB contains two switch-mode , 7W, Buck LED Drivers and one 5V, 250mW SMPS, and two microcontrollers.

The microcontrollers also read the average LED current with their ADC’s which read the LED Drivers' current sense resistor voltage via RC filters.

We are wondering about the best way to ground these converters?

Do you think that the gold line , in the picture below, is necessary to make the 5V ground the same as the other grounds?

Here is the diagram, which i wonder if it's right or not.?

https://i49.tinypic.com/2zhr60y.jpg

 

[IanP]

The simplest and most effective way of grounding circuits such as yours is to implement a ground plane on the board ..
All you have to do is make sure that the component 0V connections, which carry the return path through, have a short and direct connection to the 0V plane ..
The return current for each signal automatically finds its own preferential path through the plane and the geometry ensures that this path has the least enclosed loop area and therefore the least total path inductance ..

IanP

 

[eem2am]

Unfortunately our PCB is so heavily populated on both sides that there is no room for a ground plane.