SDAA082 August   2025 TLC69601-Q1 , TLC69604-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2Long CCSI Daisy Chain Challenges
    1. 2.1 CCSI CLK_O Duty Cycle Increase Issues
    2. 2.2 CCSI Frequency Design Consideration
  6. 3TLC69699-Q1 Connectivity IC Design
    1. 3.1 CCSI Control on the CLK_O Duty Cycle and Data Rate
    2. 3.2 Optimized Fault Readback Scheme with FAULT Signal
    3. 3.3 TXFIFO Configuration
  7. 4Summary
  8. 5References

Abstract

Local dimming backlight is widely used and gets more popular in automotive display application to provide excellent user experiences such as better image contrast ratio. The TLC696xx-Q1 family is TI's 16-channel automotive local dimming LED driver that supports both direct and 2/4/8 time-multiplexing control.

The latest display backlight board can implement thousands of LEDs to achieve higher contrast ratio and thinner module thickness. More dimming zones require more local dimming LED drivers in a single daisy chain. The TLC696xx-Q1 family can have clock duty cycle increase challenges under long a Continuous Clock Serial Interface (CCSI) daisy chain configuration, which limits the maximum cascaded number.

This application note explains the clock duty cycle increase issue root cause and proposes an effective design to support more cascaded drivers based on the TLC69699-Q1 connectivity IC.