If the answer to how much ripple is too much, or how little ripple is good enough is in all cases, ³it depends,² then does that mean that the pursuit of power integrity has a purely functional pass/fail criteria; i.e., that the unit operates properly, as opposed to a specific target on ripple level?
Ken Javor Phone: (256) 650-5261 From: John Woodgate <j...@woodjohn.uk> Date: Sat, 7 Apr 2018 17:58:36 +0100 To: Ken Javor <ken.ja...@emccompliance.com>, <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] Power Integrity Question I don't think that there is a general rule that doesn't have so many exceptions as to be useless. Even a 'simple' audio power amplifier can show this. A conventional linear amplifier can have very good PSRR (power supply rejection ratio) but a Class D amplifier has zero dB PSRR - none at all. John Woodgate OOO-Own Opinions Only J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> Rayleigh, Essex UK On 2018-04-07 17:41, Ken Javor wrote: > Power Integrity Question There are many learned books/papers/discussions on > how to achieve proper power integrity by way of proper PCB layout and proper > capacitor decoupling techniques, but what is the goal? I don't mean the > functional goal, which is obvious, but rather what is the metric? Is it > ripple voltage peak-to-peak, maximum excursion, minimum excursion, some rms > value, or...? > > This question is decoupled from achieving PI for the purpose of controlling > radiated emissions: just asking how close to pure unadulterated dc a dc rail > must be in order to be considered properly functional. > > Understand the answer will be different for an analog rail vs. a digital one, > and for different digital rails, but appreciate insight into what constitutes > acceptable power quality for all dc rails used in a typical piece of > electronics. > > Thank you, > > Ken Javor > Phone: (256) 650-5261 > > > - > ---------------------------------------------------------------- > > > 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 > <emc-p...@ieee.org> > > > 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 <sdoug...@ieee.org> > Mike Cantwell <mcantw...@ieee.org> > > > For policy questions, send mail to: > Jim Bacher <j.bac...@ieee.org> > David Heald <dhe...@gmail.com> > - ---------------------------------------------------------------- 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 <emc-p...@ieee.org> 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 <sdoug...@ieee.org> Mike Cantwell <mcantw...@ieee.org> For policy questions, send mail to: Jim Bacher: <j.bac...@ieee.org> David Heald: <dhe...@gmail.com>
