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???
02/11/08 18:23
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#150609 - This is a real disappointment
Responding to: ???'s previous message
Erik Malund said:
What magnitude of noise and ripple have you observed with your switchers?
the magnitude of noise an ripple "I have observed" will, of course, be proportional to how much filtering I put on the board.

So, how much did you observe, or, as is your usual practice, did you not attempt to observe anything at all?

I routinely add a pi filter after the switcher and have absolutely no interest in knowing what the noise an ripple would be should I decide to save those $0.11 which I have no intention of doing.

How does Vcc behave after power is switched off?
Just like any other form of regulation of course You stop supplying your filter capacitors, and your filter capacitors start discharging.

This reaffirms my previous conclusion, namely, that you've not bothered to observe anything at all in your designs. Do you really just stick things in and hope they do what you expect?

Erik


With all the claims you've made about how things work, whether in RESET or Commm's, I'd have thought you'd have examined the your own work product at least superficially.

However, it seems you've never, ever, looked at the Vcc of your designed product after it's assembled, just to see what the behavior of Vcc is. Don't your products have to meet specifications of any sort? Don't you wonder whether they meet those specifications?

Do you have any idea what the power-gnd noise levels in your products are? Do you even care?

The switchers I've used don't behave in the same way as linear supplies. The some of the linear regulators work differently, too. Apparently you haven't noticed that, yourself. I wonder why that is.

RE

All I was asking for was the numbers, ripple, random noise, Vcc rise time Vcc fall time, and maybe a comment or even a picture or two about how the supply and circuitry interact during the power-on and power-off transient.

List of 58 messages in thread
TopicAuthorDate
problems with edge triggering and noise            01/01/70 00:00      
   5v regulator,capacitors - elko and creamic            01/01/70 00:00      
      not likely            01/01/70 00:00      
         not true!            01/01/70 00:00      
   How much noise?            01/01/70 00:00      
      using a 78L05 voltage regulator IC with 220 uF cap            01/01/70 00:00      
         be conservative ... for now ...            01/01/70 00:00      
   First things first - Begin at the beginning            01/01/70 00:00      
      yes i agree..            01/01/70 00:00      
         photo            01/01/70 00:00      
            Well done            01/01/70 00:00      
               the "backside" :)            01/01/70 00:00      
                  Use Solder Wick as Braid            01/01/70 00:00      
                     is this ok?            01/01/70 00:00      
                        i found this strange looking woven wire?            01/01/70 00:00      
                  Perf Board Types            01/01/70 00:00      
                  Pad-Per-Hole PTH            01/01/70 00:00      
                     How much ?            01/01/70 00:00      
                        This Much            01/01/70 00:00      
                           other boards            01/01/70 00:00      
                     Here\'s what I prefer.            01/01/70 00:00      
            it looks quite acceptable, with caveats ...            01/01/70 00:00      
      How much noise!            01/01/70 00:00      
   Regulator problems..            01/01/70 00:00      
      sorry wrong measurements            01/01/70 00:00      
         Actuall, you were right, in part ...            01/01/70 00:00      
            Different caps..            01/01/70 00:00      
      one more issue            01/01/70 00:00      
         7805            01/01/70 00:00      
            Swop the pins around !!            01/01/70 00:00      
            agreed            01/01/70 00:00      
               what about switching noise and ripple?            01/01/70 00:00      
                  to RE            01/01/70 00:00      
                     This is a real disappointment            01/01/70 00:00      
                        numbers            01/01/70 00:00      
                           that's not what was asked ...            01/01/70 00:00      
                              yes and no            01/01/70 00:00      
                                 I've got lots of those ...            01/01/70 00:00      
                                    not mostly - only and who cares            01/01/70 00:00      
                                       It's what's before the filter that matters!            01/01/70 00:00      
                                          enough            01/01/70 00:00      
                                             not exactly ...            01/01/70 00:00      
                                                as stated before            01/01/70 00:00      
                                                   Nonsense!            01/01/70 00:00      
                                                      you can't stop, can you            01/01/70 00:00      
                                                         I love to see Erik backpedal            01/01/70 00:00      
                                                            Better start giving a hoot            01/01/70 00:00      
                                                               as stated so often, I DO give a hoot ...            01/01/70 00:00      
                                                                  as stated so often, I DO give a hoot ...            01/01/70 00:00      
                                                                     I think you are right            01/01/70 00:00      
                                                                        I too favour looking inside black boxes            01/01/70 00:00      
                                                                           blindly?            01/01/70 00:00      
                                                                              Erik ... you\'re headed for a disappointment            01/01/70 00:00      
                                                                                 If you accept datasheet blindly I cant help            01/01/70 00:00      
                                                                                    you do not get the point, do you?            01/01/70 00:00      
                                                                     not exactly            01/01/70 00:00      
                                                                        I never made any such claim            01/01/70 00:00      
         gee ... that's a negative regulator ...            01/01/70 00:00      

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