digital display

[jaravind]

In a 4 digit display system , we can use multiplexing and display one digit at a time using a mod-4 counter run by a high frequency clock which appears as a simultaneous display of the digits.Here we are avoiding the use of 4 BCD to seven segment decoders . But what's the point in avoiding their use when instead we are using multiplexers, demultiplexers , counter . The no.of ICs required in this case is aslo not less. So can anyone plz tell me if there are any advantages of using multiplexing in digital display systems??

 

[Exo]

Multiplexing is common to µC systems. In a µC system all the multiplexing requirements are handled by the µC, so the advantage is the lower number of IO lines required.

In a discrete system i guess it depends on cost, or the choice of the designer.

 

[jbeng]

Display current will likely be lower in mutiplexed displays, because only one display is lit at a time. For example, if you have a non-mux four-digit seven segment display with each segment drawing 10mA, displaying "8888" would be a total of 280mA (not including decimals, colons, etc.). With the multiplexed display, while the current will need to be higher per segment to get the same brightness, only one display is active at a time, therefore the total current should be lower. One problem: if your multiplex clock stops running at the higher segment current and leaves one digit "on" all the time, the excess current could damage/destroy that display.
JB

 

[jaravind]

thanx a lot for ur replies , i think i got my answer