Figure 7-2. GUI for the Fusion Digital Power Designer
7.3 Control-Loop Gain and Phase-Measurement Procedure
The TPS53915EVM-PWR587 contains a 10-Ω series resistor in the feedback loop for loop response analysis.
1. Set up the EVM as described in
and
.
2. Connect the isolation transformer to the test points marked TP5 and TP8.
3. Connect the input-signal amplitude-measurement probe (channel A) to TP10. Connect the output-signal
amplitude-measurement probe (channel B) to TP11.
4. Connect the ground lead of channel A and channel B to TP15.
5. Inject around 20 mV or less signal through the isolation transformer.
6. To measure control-loop gain and phase margin, change the frequency from 100 Hz to 1 MHz using a 10-Hz
or less post filter.
7. Disconnect the isolation transformer from the bode-plot test points before making other measurements.
• Signal injection into feedback can interfere with the accuracy of other measurements.
Test Procedure
10
TPS53915 Step-Down Converter Evaluation Module User's Guide
SLUUAS2C – OCTOBER 2013 – REVISED NOVEMBER 2021
Copyright © 2021 Texas Instruments Incorporated
