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

2.2 Efficiency

The efficiency of this EVM peaks at a load current of about 2 A and then decreases as the load current increases toward full load. Figure 2-1 shows the efficiency for the TPS54821EVM-049 at an ambient temperature of 25°C.

GUID-2C4F22E8-A35E-47C9-913E-2341F451F9DB-low.gifFigure 2-1 TPS54821EVM-049 Efficiency

Figure 2-2 shows the efficiency for the TPS54821EVM-049 using a semi-log scale to more easily show efficiency at lower output currents. The ambient temperature is 25°C.

GUID-F6B03EF1-49AC-4847-B4DC-1F977A5CD1F6-low.gifFigure 2-2 TPS54821EVM-049 Low Current Efficiency

The efficiency may be lower at higher ambient temperatures, due to temperature variation in the drain-to-source resistance of the internal MOSFET.