Breaking News
Power Tips

Power Tip 58: Power supply grounding--which camp are you in?

NO RATINGS
1 saves
Page 1 / 2 Next >
View Comments: Newest First | Oldest First | Threaded View
Bert22306
User Rank
CEO
re: Power Tip 58: Power supply grounding--which camp are you in?
Bert22306   4/5/2013 8:41:40 PM
NO RATINGS
Probabaly the reason why heated debates emerge is because no one pat rule ever seems to work across the board (ha ha, what a pun). I agree with the comment that a ground plane amounts to a large area single-point ground. Thing is, whether on a single card, or in a large system of components, I guess the one basic goal is to minimize ground currents. And the knee-jerk reaction of isolating grounds doesn't always work, to this end, because then your risk frying components when their zero volt references drift too far apart. One good solution is fiber optics.

bikeron
User Rank
Rookie
re: Power Tip 58: Power supply grounding--which camp are you in?
bikeron   4/5/2013 4:52:12 PM
NO RATINGS
Lot's of grounding issues left out in this article.. looks like a TI advert to me...

Consultofactus
User Rank
Rookie
re: Power Tip 58: Power supply grounding--which camp are you in?
Consultofactus   4/5/2013 12:21:25 PM
NO RATINGS
Much depends on the power output level of the switcher. The simplified drawing in the article shows the typical single phase SMPS chip with on-chip gate driver. With literally dozens of chips to choose from this approach reaches its practical limit around 150W. For these middle-to-lower wattage supplies a single ground consisting of a compact star ("single point") topology is adequate, but a ground plane is preferred for best EMI performance. Much above the 150W (or so) level a separate gate driver device will greatly help decouple switching transients from the SMPS chip - this is where a two-mesh power and signal ground approach is necessary. In these designs the signal ground will host the SMPS chip and associated bias and feedback scaling/filtering circuits. These larger designs also tend to be poly-phase so a separate power ground is especially important to keep the multiple high current paths away from the control circuitry. The power ground is common to the gate driver, current sense, input capacitor(s) and OVP. Of course in isolated designs like flybacks there's almost always a third isolated "ground" on the output.

an_m
User Rank
Rookie
re: Power Tip 58: Power supply grounding--which camp are you in?
an_m   4/4/2013 6:43:14 PM
NO RATINGS
Oh yes. both are a single point star ground, one is just more distributed than the other :-) and then you have , vias and components on both sides of the board, all good fun. My mark one eye ball rule of thumb is like yours. Look at the currents, keep di/dt low. and break every other rule at some point or other

Most Recent Comments
Wnderer
 
David Ashton
 
mikehibbett
 
dwhess
 
David Ashton
 
LarryM99
 
David Ashton
 
mikehibbett
 
goafrit
Radio
NEXT UPCOMING BROADCAST
How to Cope with a Burpy Comet
October 17, 2pm EDT Friday
EE Times Editorial Director Karen Field interviews Andrea Accomazzo, Flight Director for the Rosetta Spacecraft.
August Cartoon Caption Winner!
August Cartoon Caption Winner!
"All the King's horses and all the KIng's men gave up on Humpty, so they handed the problem off to Engineering."
5 comments
Top Comments of the Week
Like Us on Facebook

Datasheets.com Parts Search

185 million searchable parts
(please enter a part number or hit search to begin)
EE Times on Twitter
EE Times Twitter Feed