SLUU381B September   2009  – February 2022 TPS51220A

 

  1.   Trademarks
  2. 1 Introduction
  3. 2 Description
    1. 2.1 Typical Applications
    2. 2.2 Features
  4. 3 Electrical Performance Specifications
  5. 4 Schematic
  6. 5 Test Setup
    1. 5.1 Test Equipment
    2. 5.2 Recommended Test Setup
    3. 5.3 List of Test Points
  7. 6 Test Procedure
    1. 6.1 Line/Load Regulation and Efficiency Measurement Procedure
    2. 6.2 Output Ripple Test
    3. 6.3 Measuring Improved Light Load Efficiency
    4. 6.4 Control Architecture and OVP Select
    5. 6.5 Overcurrent Trip Level and Output Discharge Select
  8. 7 Performance Data and Typical Characteristic Curves
    1. 7.1 Efficiency
    2. 7.2 Load Regulation
    3. 7.3 Bode Plot
    4. 7.4 Transient Response
    5. 7.5 Output Ripple and Switch Node
    6. 7.6 Turn-On Waveform
    7. 7.7 Turn-Off Waveform
  9. 8 EVM Assembly Drawing and PCB Layout
  10. 9 List of Materials
  11. 10Revision History

6.3 Measuring Improved Light Load Efficiency

  1. All jumper modifications should be done with no power applied to the EVM
  2. SKIPSEL1 and SKIPSEL2 allow the user to select how the EVM operates when in light load. Table 6-1 describes each possible selection.
    Table 6-1 SKIPSEL1 or SKIPSEL2 (jumpers JP1 and JP4) Selections
    JUMPER LOCATIONMODEDESCRIPTION
    CCM (1 and 2 shorted)CCMEVM remains in continuous current mode
    AS (3 and 4 shorted) defaultAuto-skipEVM enters auto skip mode at light load, audible noise may be heard.
    OOA_L (5 and 6 shorted)OOA (< 400 kHz)EVM enters skip mode with no audible noise
    OOA_H (7 and 8 shorted)OOA (> 400 kHz)Not recommended
  3. Once a mode has been selected, efficiency and regulation measurements may be retaken. Repeat steps 3 to 11 of Section 6.1. The engineer should reduce the step current when the output is less than 1 A. Section 7 shows typical data for the various modes of operation