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???
02/16/07 18:16
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 		 #133141 - are your LEDs capable of 200mA ?
Responding to: ???'s previous message
otherwise you can not handle sunshine with 1/8 MPX.

Multiplexing 8 rows does not reduce the intensity to 1/8 for each row. I have seen the intensity drop by about 30% in my indoor display. Probably because we multiplex using a higher current.
Multiplexing 8 rows does reduce the intensity to 1/8 of what it would be at constant current. I DO KNOW that some, when multiplexing, drive the poor little LEDs to the brink of disaster.

For better solutions, read
http://www.8052.com/forum/read.phtml?id=132827

Another issue is that, for an outdoor display, intensity regulation, based on ambient light is manadatory. Thus you would only get 1/9 (8 illuminated steps, 1 sense step)

Erik

List of 43 messages in thread
TopicAuthorDate
Components for Outdoor LED Display            01/01/70 00:00      
   What are the specs?            01/01/70 00:00      
   you are already scewed            01/01/70 00:00      
      any better suggestions?            01/01/70 00:00      
         are your LEDs capable of 200mA ?            01/01/70 00:00      
            Human eye perception            01/01/70 00:00      
               percieved does not matter            01/01/70 00:00      
                  Perception is everything            01/01/70 00:00      
               LEDs are extremely nonlinear, too!            01/01/70 00:00      
                  I covered this            01/01/70 00:00      
                     I wrote -extremely non-linear-...            01/01/70 00:00      
                     that makes no sense            01/01/70 00:00      
                        Example with LTJ-811            01/01/70 00:00      
                           let the sunshine in            01/01/70 00:00      
                              LEDs appear the same in all conditions            01/01/70 00:00      
                                 Err            01/01/70 00:00      
                                    actually we have one multiplexed, however            01/01/70 00:00      
                                    King of LEDS :)            01/01/70 00:00      
                                 mux vs. pulsed            01/01/70 00:00      
                                    better ask ERIK ...            01/01/70 00:00      
                                       well, this is not so 'new'            01/01/70 00:00      
                                       more bright than outdoor....            01/01/70 00:00      
   why I want to multiplex            01/01/70 00:00      
      assumption?            01/01/70 00:00      
         the way multiplexing works            01/01/70 00:00      
            what is required?            01/01/70 00:00      
               Requirements are what you should analyze            01/01/70 00:00      
                  Backwards?            01/01/70 00:00      
                     low-side cap, low-side NPN            01/01/70 00:00      
                        One-bit memory == DC filter ???            01/01/70 00:00      
                           slow decay            01/01/70 00:00      
                              you can have NONE            01/01/70 00:00      
                                 are you sure?            01/01/70 00:00      
                                    yes, I am, yes I have            01/01/70 00:00      
                                 I agree with Erik ... at least somewhat            01/01/70 00:00      
                                    I am still CURIOUS            01/01/70 00:00      
                                       it's like a camera flash            01/01/70 00:00      
      already answered http://www.8052.com/forum/read.ph            01/01/70 00:00      
         Averages            01/01/70 00:00      
   does the A6278 LED driver multiplex too?            01/01/70 00:00      
      if you want to make a nonmultiplexed display...            01/01/70 00:00      
         that clears up a lot            01/01/70 00:00      
            sorry            01/01/70 00:00      

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