SLVU356A January   2010  – October 2021 TPS54290 , TPS54291

 

  1.   Trademarks
  2. 1Introduction
    1. 1.1 Description
    2. 1.2 Applications
    3. 1.3 Features
  3. 2TPS54291EVM-431 Electrical Performance Specifications
  4. 3Schematic
    1. 3.1 Enable Jumpers (JP1 and JP2)
    2. 3.2 Error Amplifier Outputs
    3. 3.3 Test Point Descriptions
      1. 3.3.1 Input Voltage Monitoring (TP1 and TP2)
      2. 3.3.2 Channel 1 Output Voltage Monitoring (TP3 and TP4)
      3. 3.3.3 Channel 1 Loop Analysis (TP5, TP6, TP7, and TP8)
      4. 3.3.4 Channel 1 Switching Waveforms (TP9 and TP10)
      5. 3.3.5 TPS54291 IC Ground (TP11)
      6. 3.3.6 Channel 2 Switching Waveforms (TP12 and TP13)
      7. 3.3.7 Channel 2 Loop Analysis (TP14, TP15, TP16, and TP17)
      8. 3.3.8 Output Voltage Monitoring (TP18 and TP19)
  5. 4Test Setup
    1. 4.1 Equipment
      1. 4.1.1 Voltage Source (VIN)
      2. 4.1.2 Meters
      3. 4.1.3 Loads
      4. 4.1.4 Oscilloscope
      5. 4.1.5 Recommended Wire Gauge
      6. 4.1.6 Other
    2. 4.2 Equipment Setup
      1. 4.2.1 Procedure
      2. 4.2.2 Diagram
    3. 4.3 Start-Up/Shutdown Procedure
    4. 4.4 Output Ripple Voltage Measurement Procedure
    5. 4.5 Control Loop Gain and Phase Measurement Procedure
    6. 4.6 Equipment Shutdown
  6. 5TPS54291EVM-431 Typical Performance Data and Characteristic Curves
    1. 5.1 Efficiency
    2. 5.2 Line and Load Regulation
    3. 5.3 Switch Node and Output Ripple Voltage
  7. 6EVM Assembly Drawings and Layout
  8. 7List of Materials
  9. 8Revision History

4.5 Control Loop Gain and Phase Measurement Procedure

  1. Connect a 1-kHz to 1-MHz isolation transformer to TP6 and TP8 as shown in Figure 4-3
  2. Connect the input signal amplitude measurement probe (Channel A) to TP8 as shown in Figure 4-3.
  3. Connect output signal amplitude measurement probe (Channel B) to TP6 as shown in Figure 4-3.
  4. Connect ground lead of Channel A and Channel B to TP5 and TP7 as shown in Figure 4-3.
  5. Inject 30-mV or less signal across R1 through an isolation transformer.
  6. Sweep frequency from 1 kHz to 1 MHz with 1-0Hz or lower post filter.
  7. Control loop gain can be measured by GUID-21308654-840B-4380-BD33-E9BACA59995B-low.gif.
  8. The control loop phase is measured by the phase difference between Channel A and Channel B.
  9. The control loop for Channel 2 can be measured by making the following substitutions:
    1. Change TP6 to TP16.
    2. Change TP8 to TP14.
    3. Change TP5 to TP17.
    4. Change TP7 to TP15.
  10. Disconnect the isolation transformer before making any other measurements (signal injection into feedback can interfere with the accuracy of other measurements).