Control Loop Gain And Phase Measurement Procedure; Table 6-2. List Of Test Points For Loop Response - Texas Instruments TPSM8D6C24EVM-2V0 User Manual

Test Procedure
Table 6-1. Test Points for Efficiency Measurements (continued)
Test Point Node Name
Output voltage measurement
TP18 VOUT_B
Output voltage measurement
TP22 PGND
point for VOUT– (GND)

6.3 Control Loop Gain and Phase Measurement Procedure

The TPSM8D6C24EVM-2V0 includes a 49.9-Ω series resistor in the feedback loop for V
accessible at the test points TP7, TP8, TP19, and TP20 for loop response analysis. These test points should be
used during loop response measurements as the perturbation injecting points for the loop. See the description in
Table 6-2.
Table 6-2. List of Test Points for Loop Response Measurements
Test Point Node Name
VOUT_A
Input to feedback divider of
TP7 CHA_VoutA
TP8 CHB_VoutA Resulting output of VOUT_A
VOUT_B
Input to feedback divider of
TP19 CHA_VoutB
TP20 CHB_VoutB Resulting output of VOUT_B
Measure the loop response with the following procedure:
1. Set up the EVM as described in
2. For VOUT_A, connect the isolation transformer of the network analyzer from TP7 to TP8.
3. Connect the input signal measurement probe to TP7. Connect the output signal measurement probe to TP8.
4. Connect the ground leads of both probe channels to TP3.
5. On the network analyzer, measure the Bode as TP8/TP7 (Out/In).
6. For VOUT_B, connect the isolation transformer of the network analyzer from TP19 to TP20.
7. Connect the input signal measurement probe to TP19. Connect the output signal measurement probe to
TP20.
8. Connect the ground leads of both probe channels to TP2.
9. On the network analyzer, measure the Bode as TP20/TP19 (Out/In).
10 TPSM8D6C24EVM-2V0 User's Guide
Description Comment
point for VOUT+
The pair of test points are connected near the output terminals. The voltage drop from the
output point of the inductor to the output terminals is included for efficiency measurement.
Description Comment
The amplitude of the perturbation at this node should be limited to less than 30 mV.
VOUT_A
Bode can be measured by a network analyzer with a CH_B/CH_A configuratio.n
The amplitude of the perturbation at this node should be limited to less than 30 mV.
VOUT_B
Bode can be measured by a network analyzer with a CH_B/CH_A configuration.
Section 4.2.
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. The resistor is
OUT
SLUUCK6 – DECEMBER 2021
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