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???
12/27/09 16:58
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Msg Score: +1
 +1 Informative		 #171955 - all the above
Responding to: ???'s previous message
If there's only a short signal path between the source of the data and the serial drivers .. etc etc ( http://www.8052.com/forumchat/reply/171949 )

All the above makes total sense; however the main enemy of this process was missed. The driver supply and the LED supply share the ground and I have seen LED current switching between 0 and 50A and, if the layout is not 'perfect' you will get ground bounce that is more than what's tolerable. For instance one particular brand of LED signs (do not ask which, they may have fixed it by now) will fail often enough to flicker noticeably if you have the right combination of LEDs lit and ambient light.

Erik

List of 96 messages in thread
TopicAuthorDate
LED Display Panel reliability            01/01/70 00:00      
   Serial out/serial in            01/01/70 00:00      
   you do not say            01/01/70 00:00      
      TB62706BFG            01/01/70 00:00      
   Decision by majority...            01/01/70 00:00      
   I would use CRC            01/01/70 00:00      
      I think you missed the point            01/01/70 00:00      
         Reading back the parallel outputs then?            01/01/70 00:00      
            actually not            01/01/70 00:00      
               "If" it is identical data...            01/01/70 00:00      
                  Only the bits in error will generate any flicker            01/01/70 00:00      
                     But he wants perfection!            01/01/70 00:00      
                     all the above            01/01/70 00:00      
                        So, there is a chance for flickering after all?            01/01/70 00:00      
                           If incorrectly designed            01/01/70 00:00      
                  trust and trust            01/01/70 00:00      
                  trust            01/01/70 00:00      
                     layout, layout, layout            01/01/70 00:00      
                     Some hints...            01/01/70 00:00      
                        excellent proposal!            01/01/70 00:00      
                           Principle of function...            01/01/70 00:00      
                        Main EMI Source            01/01/70 00:00      
                           Thoughts            01/01/70 00:00      
                              I do not know your part, but ...            01/01/70 00:00      
                                 Duplicate thread            01/01/70 00:00      
                                 Replies            01/01/70 00:00      
                              double posted            01/01/70 00:00      
                              reply            01/01/70 00:00      
                           RC-filtering and Schmitt-Triggers will help!            01/01/70 00:00      
                              response to above            01/01/70 00:00      
                                 Why???            01/01/70 00:00      
                                    maybe today            01/01/70 00:00      
                                       Hardly...            01/01/70 00:00      
                                          no            01/01/70 00:00      
                                             Wild speculations...            01/01/70 00:00      
                                                Mahmood            01/01/70 00:00      
                                                   No fun to poke about in a fog...            01/01/70 00:00      
                                                      The clock on top            01/01/70 00:00      
                                                   yes            01/01/70 00:00      
                                             He's not required to scroll            01/01/70 00:00      
                                                absolutely, but            01/01/70 00:00      
                                          You're right, Kai, but the frequent refresh costs less            01/01/70 00:00      
                                             Again...            01/01/70 00:00      
                                                it is, indeed!            01/01/70 00:00      
                                                   not only then            01/01/70 00:00      
                                                      PWM with the TB62706??            01/01/70 00:00      
                                                         YES, of course there is            01/01/70 00:00      
                                                            Yes, I understand, but...            01/01/70 00:00      
                                                               Good question            01/01/70 00:00      
                                                                  Digital potentiometer?            01/01/70 00:00      
                                                                     the problem here is            01/01/70 00:00      
                                                                        It seems they can be hooked together...            01/01/70 00:00      
                                                                           Look at this too...            01/01/70 00:00      
                                                                              Ok, then show me ...            01/01/70 00:00      
                                                                                 And write?            01/01/70 00:00      
                                                                                    :)            01/01/70 00:00      
                                                                                 Mahmod doesn't have multicolor LEDs!            01/01/70 00:00      
                                                                                    well, what is this then?            01/01/70 00:00      
                                                                                       Question for Mahmod            01/01/70 00:00      
                                                                                          Looks like...            01/01/70 00:00      
                                                                                          Yes            01/01/70 00:00      
                                                                                       Why from the same chip???            01/01/70 00:00      
                                                                                          limiting color choices to 'per chip'            01/01/70 00:00      
                                                                                             What flexibility?            01/01/70 00:00      
                                                                                                well, if ...            01/01/70 00:00      
                                                                                                   Dials            01/01/70 00:00      
                                                                                                      just to clarify            01/01/70 00:00      
                                                                                                         Length of chain shouldn't really matter            01/01/70 00:00      
                                                                                                         Single color LEDs            01/01/70 00:00      
                                                                                                            Vled only            01/01/70 00:00      
                                                                                                            Two questions...            01/01/70 00:00      
                                                                                                               Answers            01/01/70 00:00      
                                                                                                                  What range?            01/01/70 00:00      
                                                                                                                     Blue            01/01/70 00:00      
                                                                                                                        I would do it like that...            01/01/70 00:00      
                                                                                                                           thanks            01/01/70 00:00      
                                                                                                                              Why?            01/01/70 00:00      
                                                                                                                                 Board to Board Hopping            01/01/70 00:00      
                                                                                                                                    Of course...            01/01/70 00:00      
                                                                                                                                    one advantage, the other is ..            01/01/70 00:00      
                                                                                                                                       Not 40xx Chips As Generic Family            01/01/70 00:00      
                                                                                                                                          Clock skew?            01/01/70 00:00      
                                                                                                                                             Still very very helpful...            01/01/70 00:00      
                                                                                                                                                There are lower-resistance solutions            01/01/70 00:00      
                                                                                                                                                   On-resistance is beyond any doubt...            01/01/70 00:00      
                                                                                                                                                      I've used several '66s            01/01/70 00:00      
                                                                                                                                                         without any opinion of the 4066 option            01/01/70 00:00      
                                                                                                                                                      I didn't intend to suggest that it was wrong, Kai            01/01/70 00:00      
                                 All the filter is supposed to do is limit the slew rate            01/01/70 00:00      
                                    no, not the slew rate            01/01/70 00:00      
                                       Scope plot?            01/01/70 00:00      
                                          Maybe later on            01/01/70 00:00      
                                       Yes, that's true, but his worry was about his clocking            01/01/70 00:00      
                                          Great            01/01/70 00:00      
   suggestion            01/01/70 00:00      
   Problem Solved!!!!!!            01/01/70 00:00      

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