Texas Instruments TPS40400, Руководство пользователя

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7 Test Procedure
7.1 Line/Load Regulation and Efficiency Measurement Procedure
1. Set up EVM as described in Section 5.3 and Figure 5-2 .
2. Ensure load is set to draw 0 A
DC
.
3. Ensure all jumper configuration settings per Section 5.4.4 .
4. Increase V
IN
from 0 V to 12 V. Using DMM 1 to measure input voltage.
5. Use DMM 3 to measure output voltage V
OUT
.
6. Vary Load from 0 A
DC
to 20 A
DC
, V
OUT
should be remain in load regulation.
7. Vary V
IN
from 8 V to 14 V, V
OUT
should remain in line regulation.
8. Decrease Load to 0 A
9. Decrease V
IN
to 0 V.
7.2 Control Loop Gain and Phase Measurement Procedure
TPS40400EVM-351 contains a 49.9-Ω series resistor in the feedback loop for loop response analysis.
1. Set up EVM as described in Section 5.3 and Figure 5-2 .
2. Connect isolation transformer to test points marked TP13 and TP15.
3. Connect input signal amplitude measurement probe (channel A) to TP13. Connect output signal amplitude
measurement probe (channel B) to TP15.
4. Connect ground lead of channel A and channel B to TP14 and TP16.
5. Inject 40-mV or less signal through the isolation transformer.
6. Sweep the frequency from 100 Hz to 1 MHz with 10-Hz or lower post filter. The control loop gain and phase
margin can be measured.
7. Disconnect isolation transformer from bode plot test points before making other measurements (Signal
injection into feedback may interfere with accuracy of other measurements).
Test Procedure www.ti.com
14 TPS40400 Buck Controller Evaluation Module User's Guide SLUU535A – SEPTEMBER 2011 – REVISED JANUARY 2022
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