Texas Instruments TPS40345EVM-353, User Manual, Page: 9 / 23

Network
Analyzer
Isolation
Transformer
LOAD1
1.2V @
20A
+
-
V2
-
+
See Tip and Barrel
Measurement for
Vout ripple
V1
+
-
A1
-
+
V
IN
Oscilloscope
1M W , AC
20mV / div
20MHz
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Test Setup
9 SNVU588 – November 2017
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TPS40345EVM-353 Evaluation Module
Figure 4. Control Loop Measurement Setup
5.3 Start-Up/Shutdown Procedure
1. Verify shunt position for JP1 for desired FSS status per _________(need correct reference) .
2. Remove shunt from JP2 location if present.
3. Increase V
IN
from 0 Vdc to 12 Vdc.
4. Vary LOAD1 from 0 Adc to 20 Adc.
5. Vary V
IN
from 8 V to 14 V.
6. Decrease V
IN
to 0 V.
7. Decrease LOAD1 to 0 A.
5.4 Output Ripple Voltage Measurement Procedure
1. Follow Section 5.3 steps 1 – 5 to set V
IN
and LOAD1 to the desired operating condition.
2. Connect oscilloscope probe with exposed metal barrel to TP3 and TP4 per Figure 3 .
3. Set oscilloscope per oscilloscope for output voltage ripple measurement in Section 5.1.4 .
4. Follow Section 5.3 steps 6 and 7 to power down.
5.5 Control Loop Gain and Phase Measurement Procedure
1. Follow Section 5.3 steps 1 – 5 to set V
IN
and LOAD1 to the desired operating condition:
a. If JP1 is installed (FSS enabled), loop response data about the modulation frequency (30 kHz)
may be affected.
2. Connect a 1-kHz – 1-MHz isolation transformer to TP5 and TP7 as shown in Figure 4 .