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???
11/28/11 13:55
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 		 #184928 - still missing the point
Responding to: ???'s previous message
In linear supply design, the filter cap design is classically based on "tolerable" ripple under full load. The old (Originated with NSC) formula for computing filter cap size (before the regulator) was
8000 uF / ampere at full load / volt of tolerable ripple, or something on that order

with PFC (getting more and more mandatory) the "primary step down" will be a switcher and your linear regulator will not need concern itself with 120Hz ripple, but with ripple in the kHz/MHz range.

Erik

List of 26 messages in thread
TopicAuthorDate
a myth debunked ?            01/01/70 00:00      
   Same old?            01/01/70 00:00      
   Hhm...            01/01/70 00:00      
      no, I did not            01/01/70 00:00      
         Babble of marketing people...            01/01/70 00:00      
            read it all            01/01/70 00:00      
               There's no need for HF-ripple rejection...            01/01/70 00:00      
               ... what's more important ...            01/01/70 00:00      
                  whatever            01/01/70 00:00      
                     But the article claims it...            01/01/70 00:00      
                        even the article states            01/01/70 00:00      
                           Switchers ARE beautiful...            01/01/70 00:00      
                        do linear regulators ever "produce" ripple?            01/01/70 00:00      
                           getting more and more irrevelant            01/01/70 00:00      
                              Perhaps, but where else would ripple originate?            01/01/70 00:00      
                                 still missing the point            01/01/70 00:00      
                                    Why do you see this as "becoming more mandatory"?            01/01/70 00:00      
                                       you can't do PFC without            01/01/70 00:00      
                                          Vice versa...            01/01/70 00:00      
                                             Not so fast            01/01/70 00:00      
                                          fortunately, PSU's are not on my deliverables list            01/01/70 00:00      
                                       I'm with Eric            01/01/70 00:00      
                                          Disadvantage of switched-mode supplies...            01/01/70 00:00      
                                             Huge crest factor            01/01/70 00:00      
                                                Numbers...            01/01/70 00:00      
                           It depends on load            01/01/70 00:00      

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