SLVU479A October   2011  – August 2021 TPS54821

 

  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 Track In
      4. 1.3.4 Adjustable UVLO
      5. 1.3.5 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 Transients
    6. 2.6  Loop Characteristics
    7. 2.7  Output Voltage Ripple
    8. 2.8  Input Voltage Ripple
    9. 2.9  Powering 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

1.3.4 Adjustable UVLO

The undervoltage lockout (UVLO) can be adjusted externally using R1 and R2. The EVM is set for a start voltage of 6.528 V and a stop voltage of 6.193 V using R1 = 35.7 kΩ and R2 = 8.06 kΩ. Use Equation 3 and Equation 4 to calculate required resistor values for different start and stop voltages.

Equation 3. GUID-B58CADDC-AF00-4451-800A-0F5EF56CC9CA-low.gif
Equation 4. GUID-0BA1DABC-D259-46AA-B44F-119AD374C4FC-low.gif