SLUUCE9A December   2020  – April 2021 TPS543820 , TPS543820E

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Background
    2. 1.2 Before You Begin
    3. 1.3 Performance Characteristics Summary
  3. 2Configurations and Modifications
    1. 2.1 Output Voltage
    2. 2.2 Switching Frequency (FSEL Pin)
    3. 2.3 Current Limit, Soft-Start Time, and Internal Compensation (MODE Pin)
    4. 2.4 Adjustable UVLO
  4. 3Test Setup and Results
    1. 3.1  Input/Output Connections
    2. 3.2  Efficiency
    3. 3.3  Output Voltage Regulation
    4. 3.4  Load Transient and Loop Response
    5. 3.5  Output Voltage Ripple
    6. 3.6  Input Voltage Ripple
    7. 3.7  Synchronizing to a Clock
    8. 3.8  Start-up and Shutdown with EN
    9. 3.9  Start-up and Shutdown with VIN
    10. 3.10 Start-up Into Pre-Bias
    11. 3.11 Hiccup Current Limit
    12. 3.12 Overvoltage Protection
    13. 3.13 Thermal Performance
  5. 4Board Layout
    1. 4.1 Layout
  6. 5Schematic and Bill of Materials
    1. 5.1 Schematic
    2. 5.2 Bill of Materials
  7. 6Revision History

3.9 Start-up and Shutdown with VIN

Figure 3-30 and Figure 3-31 show the start-up and shutdown waveforms for U2 with VIN. In Figure 3-30, the VIN voltage ramps up and output voltage ramps up after the input and EN pin voltages reach their respective UVLO threshold. In Figure 3-31, the VIN voltage ramps down and the TPS543820 shuts down when the input or EN pin voltage reach their respective UVLO threshold. The rate at which VIN ramps down changes as soon as the TPS543820 is disabled because it is no longer loading the input supply.

GUID-DE7A184B-844E-4AD2-8A34-0B35C9BD5B54-low.gifFigure 3-30 U2 Start-up with VIN – 0.3-Ω Load
GUID-53E10E3A-A0D9-49C0-AC1E-8D73B05FD3C0-low.gifFigure 3-31 U2 Shutdown with VIN – 0.3-Ω Load