Datasheet: https://www.mouser.com/datasheet/2/389/st1cc40-1850179.pdf
Ok, I will come out and say it. After much Googling on grounding Buck converters, I am still a bit confused. I have read about "Star Grounding" and isolating my FB Power, and analog grounds. At the end of the day, I still find myself looking at the manufacturers datasheet and thinking that they were lazy about grounding in their demo board. It looks like they simply did a Top and Bottom copper pour and added a few multi-layer ground pads to tie them together.
Specs:
- 12VDC in from auto battery
- Stepped down to 2.9VDC (accounting for Dynamic Resistance)
- Single Cree XPL LED - Vfwd = 2.79VDC @ 3A (monster heatsink + MCPCB)
- Final product will feature qty (2) of the above circuits in parallel
My Concerns:
Vcc will be provided via high grade stranded wire soldered to Vcc pad, but I will either have to solder the wire to the pad INSIDE the FB loop (as shown), or CROSS the FB loop (across Top Layer) with the Vcc trace/solid. (which is the "better" of the two options?
Is my grounding technique sufficient? Searching similar questions it seems the verdict (in other examples) ranges from simply using vias to tie each component to bottom ground plane, to isolating the power and analog parts of the circuit, to relying on the IN/OUT capacitors to manage the ripple.
After people get their question answered, they typically do not seem to follow up with their results, so there is little, if anything, in regards to a final solution to aid in learning.
So in short: - Should I bring Vcc in on the Top Layer, crossing the FB trace located on the Bottom?
- Does it make sense to follow the vendors example and just add a few large multi-layer pads to tie into ground?
