SLVAFT1 September   2024 TPS92633-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2TPS92633-Q1 Design Considerations
    1. 2.1 Setting the Output Current
    2. 2.2 Single-LED-Short Diagnostic
      1. 2.2.1 Single-LED-Short Detection
      2. 2.2.2 Single-LED-Short Auto-Recovery
        1. 2.2.2.1 Implementation Results
  6. 3Summary
  7. 4References

2.2.2.1 Implementation Results

The application results with the recommended circuit implemented is shown in Figure 2-5 and Figure 2-6. Table 2-1 shows the components values.

Table 2-1 Component Values
R1 R2 R3 R4 R5 C1
100kΩ 10kΩ 100kΩ 100kΩ 100kΩ 1uF
Parallel Channels Exposed to SIngle-LED-Short Condition DetectionFigure 2-5 Parallel Channels Exposed to SIngle-LED-Short Condition Detection
Parallel Channels Exposed to Single-LED-Short Condition Auto-RecoveryFigure 2-6 Parallel Channels Exposed to Single-LED-Short Condition Auto-Recovery

For a supply voltage of 10V, and 5V PWM pulse of 120Hz at 35% duty cycle, if a single-LED-short fault occurs, the FAULT pin is pulled down internally, then the PWM pins are pulled low. After a time interval of 13ms, the PWM pins are pulled up until the fault is removed. The FAULT pin is released and the output current can recover to normal operation.

Step 3: Use a MCU to Sync All Retry Currents

If a MCU is available in this system and can be used to control the PWM pins and the FAULT pin, it is easy to achieve this retry current synchronization, which can be seen in Figure 2-7. The same functionally can be achieved as the retry current sync circuit above.

MCU Connection for TPS92633-Q1 Parallel ChannelsFigure 2-7 MCU Connection for TPS92633-Q1 Parallel Channels