Design Con 2015
Breaking News
Design How-To

Understand and reduce DC/DC switching-converter ground noise

NO RATINGS
Page 1 / 2 Next >
More Related Links
View Comments: Threaded | Newest First | Oldest First
Sanjib.A
User Rank
CEO
re: Understand and reduce DC/DC switching-converter ground noise
Sanjib.A   11/21/2011 6:17:55 PM
NO RATINGS
Very good article. I am going to apply the learnings into the power supply design I got involved in. I would love to see a continuation of this series for other power supply topologies as well.

zeeglen
User Rank
Blogger
re: Understand and reduce DC/DC switching-converter ground noise
zeeglen   11/21/2011 7:56:16 PM
NO RATINGS
Good article, and also would like to see more. Years ago I ran into a problem with noise from an isolated 48V to 5V converter into a fiber optic receiver, but only when the card was placed into a metal card cage. On the bench alone it worked fine. The local ground noise was common mode in the optical receiver PIN diode to the external transimpedance amplifier connection on the bench, but the metal optical receiver housing was physically installed on the card front faceplate. Placing the front faceplate at earth (chassis) ground capacitively quieted the local ground, which then caused a 3dB worse bit error rate. We ended up having to mount the optical receiver diode on the pcb and run an optical pigtail to the front faceplate connector. On a subsequent optical receiver I anticipated the problem and used a pigtail in the initial design as well as including mounting holes for a shield for the the optical receiver diode. The shield was needed, the card was stand-alone in a metal box and installing into the box caused similar converter noise problems. All that was needed was a square inch of metal on a couple standoffs at pcb ground to hide the photodiode and transimpedance input from the box.

_hm
User Rank
CEO
re: Understand and reduce DC/DC switching-converter ground noise
_hm   11/22/2011 12:36:04 AM
NO RATINGS
Interesting and informative article. Can there be webinar from Author and link available on eetimes?

abraxalito
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
abraxalito   11/22/2011 4:41:10 AM
NO RATINGS
Very interesting - but the enlarged drawing links appear to be broken on this page. Second the request for more similar articles, this is first-principle stuff so has wide applicability beyond DC-DC converters.

agk
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
agk   11/22/2011 10:36:51 AM
NO RATINGS
The inductor can be made with minimum parasitic capacitance. The bobin of the inductor to have corrugated sections and the wire is wound in these sections will reduce the parasitic capacitance very much. In turn can minimize the ground noises.

PierreBTOL
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
PierreBTOL   11/23/2011 12:10:38 PM
NO RATINGS
Concise & very interesting ! If we could have the same level of explications about the "i/o CommonMode Noise Isolated" DCDC Converter, it will be great !

studleylee
User Rank
Manager
re: Understand and reduce DC/DC switching-converter ground noise
studleylee   11/23/2011 5:36:00 PM
NO RATINGS
@PierreBTOL Loved this article! This other one was also useful in tips for common mode noise: http://www.interpoint.com/product_documents/DC_DC_Converters_Output_Noise.pdf Measurement and Filtering of Output Noise of DC/DC Converters

Fabio007
User Rank
Manager
re: Understand and reduce DC/DC switching-converter ground noise
Fabio007   11/24/2011 8:27:13 AM
NO RATINGS
Great article, I would like to get a PDF copy of it, but the print link does not seem to work. To add to comment of agk re: winding inductor with low parasitic C, another trick is to have the turns at the ends of the winding (near the connection terminals) spaced further apart compared to turns in the middle of the winding. This is an old trick used by ham-radio builders, and can result is a smaller inductor than would result from spacing all turns the same distance apart, but of course the parasitic C is a bit higher.

Sail Mike
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
Sail Mike   11/24/2011 8:58:03 AM
NO RATINGS
Missing links for larger images & cant print

BicycleBill
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
BicycleBill   11/24/2011 12:48:06 PM
NO RATINGS
There is some system bug which is preventing the "enlarge" of Figures 5 and 6 from appearing properly. Here are the direct links for those figures: http://www.eetimes.com/ContentEETimes/Documents/Schweber/C0893/C0893-Figure5.pdf AND http://www.eetimes.com/ContentEETimes/Documents/Schweber/C0893/C0893-Figure6.pdf

huanben
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
huanben   11/25/2011 6:12:40 AM
NO RATINGS
GOOOOOOOOOOOOOOOOOD

PierreBTOL
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
PierreBTOL   11/26/2011 8:14:59 AM
NO RATINGS
@ studleylee: Very useful, thank you for that link !

Jerry.Deng
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
Jerry.Deng   11/29/2011 7:31:54 PM
NO RATINGS
good article. However it assumes constant current on load, most IC actually works at constant voltage with varing current dynamically, any idea?

Swamp
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
Swamp   12/1/2011 1:53:00 PM
NO RATINGS
As a slight improvement, it might have been informative to include the specific physical location of the input capacitor described in your article (between the Vin pin of the converter IC/switch transistor and the anode of the switching diode). Great article, Jeff -thanks!

SLN MURTHY
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
SLN MURTHY   5/15/2012 5:43:39 AM
NO RATINGS
It is an excellent article. Jerry Deng's point is valid and impact of varying current in a constant voltage environment would add more punch to this basic understanding.

silker
User Rank
Rookie
re: Understand and reduce DC/DC switching-converter ground noise
silker   4/27/2013 9:28:30 PM
NO RATINGS
Can we say that RC inductor current sense method has the drawback of ground line pollution? We intentionally put a capacitor (along a resitor resistor) between inductor legs.

Most Recent Comments
perl_geek
 
AZskibum
 
AZskibum
 
AZskibum
 
AZskibum
 
mhrackin
 
DrQuine
 
R_Colin_Johnson
 
R_Colin_Johnson
Radio
LATEST ARCHIVED BROADCAST
EE Times Senior Technical Editor Martin Rowe will interview EMC engineer Kenneth Wyatt.
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
Flash Poll