Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Output active filter .

Status
Not open for further replies.

vimalkhanna

Full Member level 6
Joined
Aug 7, 2010
Messages
322
Helped
55
Reputation
110
Reaction score
53
Trophy points
1,308
Location
delhi
Activity points
3,224
Hi Guys ,
My circuit for DC converter is 2400watts delivery at 48VDC
design operation is for -30*C ambients where capacitors malfunction.
The tantallums/multilayers ceramic are unable to withstand ripples .
Suggest Active ripple filters at 1.5MHz flyback switchings to give smooth output with >40dB atten
Analog opamp design is useful with chebychev slope ..
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
50,502
Helped
14,562
Reputation
29,396
Reaction score
13,592
Trophy points
1,393
Location
Bochum, Germany
Activity points
289,604
It's absurd to implement an active filter for this purpose. You'll find however a lot of capacitors that can work at -30 degree C.

Most foil capacitors as well as X5R/X7R ceramics are specified down to -55 °C.
 

vimalkhanna

Full Member level 6
Joined
Aug 7, 2010
Messages
322
Helped
55
Reputation
110
Reaction score
53
Trophy points
1,308
Location
delhi
Activity points
3,224
That is right for the -30*C operation.
However , Zo being very low and fundamental freq . suppression is 1.5MHz ,the foil are inoperative .
The ceramics X5R punctures and loses value after 30mins operation.
The tantallum caps burst .as they cannot withstand large ripple contents
 

tony_lth

Advanced Member level 5
Joined
Jul 28, 2010
Messages
2,069
Helped
377
Reputation
756
Reaction score
368
Trophy points
1,363
Location
Beijing
Activity points
12,482
There are plastic film capacitors that can stand very low temperature, you can search in Panasonic.
 

FvM

Super Moderator
Staff member
Joined
Jan 22, 2008
Messages
50,502
Helped
14,562
Reputation
29,396
Reaction score
13,592
Trophy points
1,393
Location
Bochum, Germany
Activity points
289,604
However , Zo being very low and fundamental freq . suppression is 1.5MHz ,the foil are inoperative .
There are rather different form factors with different inductance values. But of course, one need to know the filter parameters to determine if it's feasible
The ceramics X5R punctures and loses value after 30mins operation.
So you are operating the capacitors beyond their specification? Did you measure or at least calculate the ripple currents?
The tantallum caps burst .as they cannot withstand large ripple contents
Yes, sounds plausible.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top