SLVAFP4 October   2023 TLC59283

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction of Time-Multiplexing With TLC59283
  5. 2TLC59283 Ringing Simulation Assessment
    1. 2.1 Small Parasitic Inductance of Vin and GND On-Board Without C_sink
      1. 2.1.1 Only Add L_LED1
      2. 2.1.2 Only Add L_LED2
    2. 2.2 Parasitic Inductance of Vin and GND On-Board With 4.7nF C_sink
      1. 2.2.1 L_LED1 Reach 3uH
      2. 2.2.2 L_LED2 Reach 3uH
    3. 2.3 Parasitic Inductance of Vin and GND on Customer’s Board Without C_sink
      1. 2.3.1 Only Add L_LED1
      2. 2.3.2 Only Add L_LED2
      3. 2.3.3 Add L_LED1 and L_LED2
    4. 2.4 Parasitic Inductance of Vin and GND on Customer’s Board With 4.7nF C_sink
  6. 3TLC59283 Ringing Bench Assessment
    1. 3.1 Bench Test Without R_sink and C_sink
    2. 3.2 Bench Test With 1nF C_sink
    3. 3.3 Bench Test With 10nF C_sink
    4. 3.4 Bench Test With 150 Ω R_sink
      1. 3.4.1 Bench Test With 10nF C_sink and 150 Ω R_sink
  7. 4Calculation of Resistor Value in RC Circuit
  8. 5Summary
  9. 6References

1 Introduction of Time-Multiplexing With TLC59283

TI proposed a scheme to realize time-multiplexing with TLC59283 if there are not enough I/Os in the system to control the transistor, a block diagram similar to Figure 1-1 can be used to drive 64 LEDs. TLC59283 uses eight PNP transistors to switch the common lines and forms a 8-multiplexing scheme. The eight transistors are controlled by the outputs of the TLC59283 so it reduces the I/O count. The more details can be seen in Use TLC59283 for LED Indication with Better Brightness Uniformity, Smaller Size, and Ghosting Elimination.

GUID-20231023-SS0I-RK9W-WM86-RNQV6FMKVTCC-low.svg Figure 1-1 Time-Multiplexing Circuit Using TLC59283 With Less MCU I/Os

In the market of smart home appliances, the previous proposed scheme can cause output ringing since the leads are so long to result a relatively large parasitic inductance. This paper proposed a design for the ringing phenomenon and provided the result of simulation and bench test.