SLVU777A September   2012  – November 2021 TPS54020

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Background
    2. 1.2 Performance Specification Summary
    3. 1.3 Modifications
      1. 1.3.1 Output Voltage Setpoint
      2. 1.3.2 Slow-Start Time
      3. 1.3.3 Adjustable UVLO
      4. 1.3.4 Input Voltage Rails
  3. 2Test Setup and Results
    1. 2.1  Input / Output Connections
    2. 2.2  Efficiency
    3. 2.3  Output Voltage Load Regulation
    4. 2.4  Output Voltage Line Regulation
    5. 2.5  Load Transient
    6. 2.6  Control Loop Response
    7. 2.7  Output Voltage Ripple
    8. 2.8  Input Voltage Ripple
    9. 2.9  Start Up
    10. 2.10 Pre-Bias Start Up
    11. 2.11 Hiccup Mode Current Limit
  4. 3Board Layout
    1. 3.1 Layout
  5. 4Schematic and Bill of Materials
    1. 4.1 Schematic
    2. 4.2 Bill of Materials
  6. 5Revision History

1.3.2 Slow-Start Time

The slow-start time is adjusted by changing the value of C14. Use Equation 2 to calculate the required value of C14 for a desired slow-start time.

Equation 2. GUID-FC52973C-FEC0-4BC7-9F26-9E7677BC6B3E-low.gif

Where:

TSS = desired slow start time
ISS = slow start charging current = 2.3-µA nominal
VREF = 0.6-V reference voltage

The EVM is set for a slow-start time of approximately 26 ms using C14 = 0.1 μF.