SLUUD52 August   2024 TPS544E27

 

  1.   1
  2.   Description
  3.   Get Started
  4.   Features
  5.   Applications
  6.   6
  7. 1Evaluation Module Overview
    1. 1.1 Introduction
      1. 1.1.1 Before You Begin
    2. 1.2 Kit Contents
    3. 1.3 Specifications
    4. 1.4 Device Information
  8. 2Hardware
    1. 2.1 Test Equipment
      1. 2.1.1 Voltage Source
      2. 2.1.2 Oscilloscope
      3. 2.1.3 Multimeters
      4. 2.1.4 Output Load
      5. 2.1.5 Fan
      6. 2.1.6 USB-to-GPIO Interface Adapter:
      7. 2.1.7 Recommended Wire Gauge
    2. 2.2 List of Test Points, Jumpers, and Connectors
    3. 2.3 Efficiency Measurement Test Points
    4. 2.4 Control Loop Gain and Phase Measurement
    5. 2.5 External 5V Bias to Enhance Efficiency
    6. 2.6 Input Current Measurement
  9. 3Software
    1. 3.1 Opening the PMBus® Fusion GUI
    2. 3.2 Monitor Page
    3. 3.3 Status Page
  10. 4Implementation Results
    1. 4.1 Performance Data and Typical Characteristics Curves
  11. 5Hardware Design Files
    1. 5.1 Schematic
    2. 5.2 PCB Layout
    3. 5.3 Bill of Materials
  12. 6Additional Information
    1. 6.1 Trademarks

2.4 Control Loop Gain and Phase Measurement

The TPS544E27EVM includes a R11 10Ω series resistor in the feedback loop for VOUT. The resistor is accessible at the test points TP16 (BODE_CHA) and TP10 (VOUT/BODE_CHB) for loop response analysis. These test points must be used during loop response measurements as the perturbation injecting points for the loop . See the description in Table 2-5.

Table 2-5 List of Test Points for Loop Response Measurements
Test PointNode NameDescriptionComment
TP16BODE_CHAInput to feedback divider of VOUTThe amplitude of the perturbation at this node must be limited to less than 30mV.
TP10BODE_CHBResulting output of VOUTBode can be measured by a network analyzer with a CHB/CHA configuration.

Measure the loop response with the following procedure:

  1. Set up the EVM as described in Section 2.
  2. For VOUT, connect the isolation transformer of the network analyzer from TP16 to TP10.
  3. Connect the input signal measurement probe to TP16. Connect the output signal measurement probe to TP10.
  4. Connect the ground leads of both probe channels to TP13 (PGND).
  5. On the network analyzer, measure the Bode as TP16/TP10 (In/Out).