Intuitively, I would think that any measures taken to de-synchronize the switching of the power supplies would also improve conducted emissions.
> -----Original Message----- > From: Pat Lawler [SMTP:[email protected]] > Sent: Wednesday, July 30, 2003 10:31 AM > To: EMC-PSTC > Subject: Synchronizing DC-DC converters to reduce emissions? > > > We are designing a switching power supply for a customer that has > multiple outputs. Due to the tight regulation requirements, all > outputs have their own PWM modulators and control loops. > > The customer feels the RF emissions (as measured by CISPR 11) will be > reduced by synchronizing the frequencies of all the converters. I > think synchronizing the PWM sections will make the total power supply > emissions as high as possible (emissions are coherent?). > > 1) What has been your experience with controlling noise from multiple > switching power supplies? Is synchronizing a good idea? > > 2) If the supplies are synchronized, would a phase shift between > converters (avoiding simultaneous switching of all converters) help? > > Thanks, > --- > > > ------------------------------------------- > This message is from the IEEE EMC Society Product Safety > Technical Committee emc-pstc discussion list. > > Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ > > To cancel your subscription, send mail to: > [email protected] > with the single line: > unsubscribe emc-pstc > > For help, send mail to the list administrators: > Ron Pickard: [email protected] > Dave Heald: [email protected] > > For policy questions, send mail to: > Richard Nute: [email protected] > Jim Bacher: [email protected] > > Archive is being moved, we will announce when it is back on-line. > All emc-pstc postings are archived and searchable on the web at: > http://www.ieeecommunities.org/emc-pstc This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] Archive is being moved, we will announce when it is back on-line. All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
