|
Home > Archive > Electrical code Compliance > October 2007 > EMI filter for 120W SMPS
You are viewing an archived Text-only version of the thread.
To view this thread in it's original format and/or if you want to reply to
this thread please [click here]
| Author |
EMI filter for 120W SMPS
|
|
| omilo2 2007-10-11, 3:25 am |
| I've been working on getting my 120W current-mode SMPS to pass the
conducted EMC test. The switching freq is 100kHz and has two stages PFC
and PWM integrated in one controller the ON Semi NCP1603. I've tried
different filter combinations but unfortunately each combination only
works for one load condition. For example:
1) when I have two common-mode choke and some X2 and Y2 capacitors that
gave me a good conducted EMI result, but only with <10% load.
2) Another combination with 2 ferrite beads in series, each for the active
and neural like before the common-mode choke gave me a good result at full
load.
3) When I added a aluminium heatsink/base to the board, none of the above
filters work. The conducted noise level shoot up at about 10MHz -15MHz
range.
Anyone has any idea on how I should tackle this problem? Or does anyone
know of any good design resources (books or website) that gives good
practical advice on EMI filter design for SMPS? I have millions of
questions in my head that I need answers for. Frustrating....grrrh!
| |
| hrhofmann@att.net 2007-10-12, 5:25 pm |
| On Oct 11, 12:18 am, "omilo2" <j...@fabtronics.com.au> wrote:
> I've been working on getting my 120W current-mode SMPS to pass the
> conducted EMC test. The switching freq is 100kHz and has two stages PFC
> and PWM integrated in one controller the ON Semi NCP1603. I've tried
> different filter combinations but unfortunately each combination only
> works for one load condition. For example:
> 1) when I have two common-mode choke and some X2 and Y2 capacitors that
> gave me a good conducted EMI result, but only with <10% load.
> 2) Another combination with 2 ferrite beads in series, each for the active
> and neural like before the common-mode choke gave me a good result at full
> load.
> 3) When I added a aluminium heatsink/base to the board, none of the above
> filters work. The conducted noise level shoot up at about 10MHz -15MHz
> range.
>
> Anyone has any idea on how I should tackle this problem? Or does anyone
> know of any good design resources (books or website) that gives good
> practical advice on EMI filter design for SMPS? I have millions of
> questions in my head that I need answers for. Frustrating....grrrh!
Are you a member of the IEEE EMC Society?
Where are you located?
H. R.(Bob) Hofmann
| |
| hrhofmann@att.net 2007-10-16, 3:25 am |
| On Oct 12, 5:17 pm, "hrhofm...@att.net" <hrhofm...@att.net> wrote:
> On Oct 11, 12:18 am, "omilo2" <j...@fabtronics.com.au> wrote:
>
>
>
>
>
>
>
> Are you a member of the IEEE EMC Society?
>
> Where are you located?
>
> H. R.(Bob) Hofmann- Hide quoted text -
>
> - Show quoted text -
The OP never responded so I guess any help is not needed.
H. R. (Bob) Hofmann
|
|
|
|
|