Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

total Forward Current in a 7 segment and its individual segment

Status
Not open for further replies.
D

dann11

Full Member level 3
Full Member level 3
Joined
Oct 22, 2015
Messages
166
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,296
Activity points
2,742
Hi! I am trying to design a circuit with the use of a 7 segment display, I am just a little confused about it's forward current. Should the current consideration be in between each segment or the current as a whole?

Here is the datasheet of the 7 segment that I am using, in this, it shows the current requirements of the 7segment but I am not quite sure if they are for individual internal diode? or not? or are they?

For example is at the Absolute Maximum Ratings, the DC forward current and the Peak forward current, does these values represent the requirement as whole? And even the different graphs, do they represent the whole 7segment or just the invidual internal diode requirement?

https://www.kingbrightusa.com/images/catalog/spec/SA32-21EWA-SBI-F01.pdf
 

And even the different graphs, do they represent the whole 7segment or just the invidual internal diode requirement?
Click to expand...
Clearly the individual internal diode requirement.
 
  • Like
Reactions: dann11

    D

    dann11

    Points: 2
    Helpful Answer Positive Rating
They are specified 'per segment' not per diode or whole device. The reason for specifying by segement and not diode is some (not that particular one) 7-segment displays use more than one diode per segment. Small displays are OK with one LED per segment but larger ones require more LEDs to evenly illuminate the segment area. Having said that, most displays with more then one LED have them wired in series so they need more voltage but the current may still be the same.

Brian.
 
  • Like
Reactions: dann11

    D

    dann11

    Points: 2
    Helpful Answer Positive Rating
betwixt said:
They are specified 'per segment' not per diode or whole device. The reason for specifying by segement and not diode is some (not that particular one) 7-segment displays use more than one diode per segment. Small displays are OK with one LED per segment but larger ones require more LEDs to evenly illuminate the segment area. Having said that, most displays with more then one LED have them wired in series so they need more voltage but the current may still be the same.

Brian.
Click to expand...

I see. Do datasheet specify how many LED are there in a segment? or it is not necessary at all since the overall voltage and current per segments are specified?
 

There is only one LED per segment in that particular display because of its small size but bigger ones can have several LEDs in series and the data sheet will give the total Vf for each segment. Normally, as all the segments are of similar size, they will have the same number of LEDs in them with the exception of dots (decimal points or digit spacers) which usually only have one, regardless of the digit size.

Brian.
 
  • Like
Reactions: dann11

    D

    dann11

    Points: 2
    Helpful Answer Positive Rating
Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top