Typically we handle each DC to DC as separate entities and filter locally. Having said that - are you trying to solve and EMI problem or trying to prevent one?
Thanks! Charles Grasso W: 303-706-5467 From: James Pawson (U3C) [mailto:[email protected]] Sent: Tuesday, June 04, 2019 1:45 AM To: [email protected] Subject: [PSES] DC/DC EMI Input Filter Stability This message originated outside of DISH and was sent by: [email protected]<mailto:[email protected]> Morning all, I'm designing an EMI filter for a DC input power line that has four DC/DC converters all running off it. I know that the output impedance of the EMI filter needs to be much lower than the input impedance of the DC/DC converter to prevent oscillation/instability. But what happens when there are multiple DC/DC converters running in parallel from the same input? How do the input impedances interact? Do they appear in parallel or do the control loops isolate stability issues to individual converters? My understanding from this paper - http://www.ti.com/lit/an/slua929a/slua929a.pdf - is that the control loop and output filter of the DC/DC contributes to the stability analysis. If so, then each DC/DC can be considered individually with the filter being designed to have margin to the lowest input impedance of all of the converters. This is instead of just adding all the input impedances in parallel. Is my understanding correct? Thanks in advance, James James Pawson EMC Problem Solver Unit 3 Compliance Design for EMC / Pre Compliance / Problem Solving / EMC Testing / Consultancy / Environmental & Vibration www.unit3compliance.co.uk<http://www.unit3compliance.co.uk/> -- 07811 139957 Opening Hours: Tuesday to Friday, 0830 to 1800. Closed Monday. Connect with me on LinkedIn<https://www.linkedin.com/in/james-pawson-unit-3-compliance/> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
