SLUAAT3 November   2023 TPS56837

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Why Soft Start is Needed
  5. 2Soft Start Principle
    1. 2.1 General Principle
    2. 2.2 Internal and External Soft Start
  6. 3Behaviors Related to Soft Start of TPS56837
    1. 3.1 Soft Start Sequence
    2. 3.2 Soft Start Discharge
    3. 3.3 UVP Hiccup Time
  7. 4How to Co-Lay TPS56837 and TPS56637
    1. 4.1 Pinout Differences of TPS56837 and TPS56637
    2. 4.2 Co-lay Guidance TPS56837 and TPS56637
  8. 5Summary
  9. 6References

1 Why Soft Start is Needed

The soft start function is initiated after EN enable and input voltage reaches UVLO. The soft start circuitry controls the output voltage slope to prevent excessive inrush current, maintain a controlled output voltage, and avoid unwanted voltage overshoots and drops during power management IC start up.

Figure 1-1 shows the difference of output voltage versus time with and without the soft start function. The figure shows that the output voltage overshoots and drops without soft start function. So, soft start is needed for power management IC.

GUID-20231121-SS0I-KMF8-HNPM-N3Q9S4FMDLH9-low.svgFigure 1-1 Output Voltage With and Without Soft Start Function