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TLC6984: RGB LED display driver IC selection and design guideline

Gaurav Patni
Prodigy 40 points
Part Number: TLC6984
Other Parts Discussed in Thread: TLC6983, TLC5948A, TLC5955, TLC5929

Hi , 

I am working on designing LED display message board with following details.

  1. Dimensions -  1800mm x 300mm 
  2. RGB LED - colour display 
  3. LED pixel resolution  - less than 3mm 
  4. Display should have clear & bright visuals 
  5. able to display scrolling text as well as animated videos of high resolution 

I am new to the LED display board deign . Request you to provide steps to architect the deign. Following are my basic queries 

  1. Does TI has solution for such big size LED display design ? Please suggest suitable LED display driver IC part no ? I have tentatively selected TLC6984
  2. How many Driver ICs do I need for the above display ? how to connect / integrate all the driver ICs to make a single display solution ?
  3. How to calculate the power requirement ? 
  4. Any reference design or application note to understand designing such a big size display & display the content with good clarity & resolution ?


Thanks & Regards,
Gaurav 

  • 0
    TI__Mastermind 19375 points

    Hi Gaurav,

    Sorry but I am in business travel these days. I will reply to you when I am back in office next Monday.

    BR,

    Steven

  • 0
    TI__Mastermind 19375 points

    Hi Gaurav,

    • Please specify your pixel pitch more precise rather than "<3mm" so that we can recommend the proper device for you.
    • Here is a reference design for your reference: TIDA-00161 reference design | TI.com

    Best Regards,

    Steven

  • 0 in reply to Steven Li
    Prodigy 40 points

    Hi Steven , 

    Thanks for your reply.

    We need to design two types of display unit 

    1) 1800 x 300mm size with 2.5mm pitch ( bigger display variant ) , colour display 
    2)  720 x 80mm size ( 144x 16 pixel ) with 5mm pitch ( smaller variant ) , colour display 

    Based on above inputs please suggest suitable driver solution ( Two different Driver ICs will be ok if its saves significant cost ) .


    Best Regards,
    Gaurav 

  • 0 in reply to Gaurav Patni
    TI__Mastermind 19375 points

    Hi Gaurav,

    • For 2.5mm (lower current requirement), you may consider using TLC6983 / TLC6984 with internal scan FET.
    • For 5mm (higher current requirement), you may consider using TLC5948A / TLC5929 / TLC5955 with external scan FET.

    Best Regards,

    Steven

  • 0 in reply to Steven Li
    Prodigy 40 points

    Hi Steven , 

    Thanks for your reply.

    As per datasheet of TLC6983 , it support 2 level of multiplexing i.e. 32x32 RGB led matrix only .
    Could you please explain how to arrange / connect more than 2 TLC6983  driver ICs to control 1800 x 300mm RGB display of 2.5mm pitch (   which may have approx 720 x 120 LED matrix ) ? any reference schematic with sample code example for large LED panel design will be helpful. 

    Thanks ,
    Gaurav 

  • 0 in reply to Gaurav Patni
    TI__Mastermind 19375 points

    Hi Gaurav,

    • TLC6983 can support up to 2 stackable devices (i.e., Two TLC6983 can be stacked up to control up to 32 x 32 RGB pixels). TLC6984 can support up to 4 stackable devices (i.e., Four TLC6983 can be stacked up to control up to 64 x 64 RGB pixels). You can find the comparison table in [Q1] from this [FAQ].
    • For a large tile, you can compose it by cascading multiple matrixes together in a daisy chain. (You can refer to the below picture to see how two 32 x 32 matrixes are cascaded to form a 32 x 64 tile.) You can have several daisy chains (tiles) to compose a larger panel. (An example is in Section 9.2.1 Design Requirements from TLC6983 datasheet.)

    Cascading-devices

    Best Regards,

    Steven

  • 0 in reply to Steven Li
    Prodigy 40 points

    Thanks Steven for the details .

    Could you please let me know how many matrices we can connect in daisy chain to form a large display ? Is there nay technical limit for that ? if yes then how to calculate the limit ?


    Also if we need say 64 x 16 lines only ( in above example of 64x32 )  then what to do for the reaming unused lines & LED connections ?

    Thanks ,
    Gaurav Patni

  • +1 in reply to Gaurav Patni
    TI__Mastermind 19375 points

    Hi Gaurav,

    The maximum number of devices you can connect in a daisy chain depends on several factors, such as 

    • The maximum number of cascaded devices the driver chip can support (32 devices for TLC698x)
    • How fast your controller chip can transmit the data
    • How fast your driver chip can receive the data 
    • How fast your data signals can transmit successfully between chips without signal integrity problems

    If you are going to use 64 x 16 lines, then you can use 4 x TLC6983 in independent mode. You can refer to section 8.3.1.1 Independent Mode from the TLC6983 datasheet. (A capture of the datasheet is shown below)

    Best Regards,

    Steven

  • 0 in reply to Steven Li
    Prodigy 40 points

    Hi Steven , 

    Thanks for your support till now.
    Let me study all the technical documents & Application notes based on you reply.

    Thanks & Regards,
    Gaurav

  • 0 in reply to Gaurav Patni
    TI__Mastermind 19375 points

    Hi Gaurav,

    You are welcome. Please feel free to contact me again if you have any further questions.

    Best Regards,

    Steven