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TLC5920 LED matrix display problems

Eric Lo63813
Intellectual 450 points
Other Parts Discussed in Thread: TLC5920

TLC5920 LED matrix display problems. Figure1 is ideal LED matrix display. But the test results as Figure 2, the red LED light leakage in S13-S15.

Thanks for your support ~~

Figure 1

Figure 2

Application Circuit

COM6(CH2) vs S4 (CH1)。 S4 - COM6=1.3V

 

  • 0
    TI__Intellectual 955 points

     Hello Eric,

     the followings may be able to solve the issue.

    1. Extend BLANK pulse H level.

       I think you change CSEL0/1/2 level setting while BLANK signal level is H. If BLANK H pulse is 1us now, then extend the pulse duration to 2us or more.

    2. LATCH signal input timing.

       If LATCH rising edge is input at the middle of BLANK H pulse duration, then the rising edge timing should be input just after BLANK rising edge is input.

    3. Add pull up register.

       If no pulll up register is place between COMn and VCC, try to place the register for pullup COMn. The register value would be 1K~100Kohm. But this solution case, total board consumption current is incresed.

     Best regards,

     Kazuya Nakai