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10 Test Procedure
10.1 Line and Load Regulation Measurement Procedure
Use the following procedures for line and load regulation measurement.
1. Connect VOUT to J3 and VOUT_GND to J5 Figure 7-1 .
2. Ensure that the electronic load is set to draw 0 A
DC
.
3. Connect VIN to J1 and VIN_GND to J2 Figure 7-1 .
4. Connect the USB interface adapter as shown in Figure 7-3 .
5. Increase V
IN
from 0 V to 12 V using the digital multimeter to measure input voltage.
6. Launch the Fusion GUI software. See the screen shots in Section 12 for more information.
7. Configure the EVM operating parameters as desired.
8. Use the other digital multimeter or the oscilloscope to measure output voltage V
OUT
at TP2 and TP10 as you
vary the external voltage source.
Table 10-1. List of Test Points for Line and Load Measurements
Test Point Node Name Description
TP2 LocS+ Sense VOUT + locally across C5. Use for efficiency and ripple measurements
TP10 LocS- Sense VOUT - locally across C5. Use for efficiency and ripple measurements
TP4 PVIN Sense VIN + across C10
TP13 PGND Sense VIN - across C10
9. Vary the load from 0 A
DC
to maximum rated output 40 A
DC
. V
OUT
must remain in regulation as defined in
Table 3-1 .
10. Vary V
IN
from 5 V to 16 V. V
OUT
must remain in regulation as defined in Table 3-1 .
11. Decrease the load to 0 A.
12. Decrease V
IN
to 0 V or turn off the supply.
10.2 Efficiency
To measure the efficiency of the power train on the EVM, it is important to measure the voltages at the correct
location. This is necessary because otherwise the measurements will include losses in efficiency that are not
related to the power train itself. Losses incurred by the voltage drop in the copper traces and in the input and
output connectors are not related to the efficiency of the power train, and they must not be included in efficiency
measurements.
Table 10-2. List of Test Points for Efficiency Measurements
Test Point Node Name Description
TP2 LocS+ Sense VOUT + locally across C5. Use for efficiency and ripple measurements
TP10 LocS- Sense VOUT - locally across C5. Use for efficiency and ripple measurements
TP4 PVIN Sense VIN + across C10
TP13 PGND Sense VIN - across C10
Input current can be measured at any point in the input wires, and output current can be measured anywhere
in the output wires of the output being measured. Using these measurement points result in efficiency
measurements that do not include losses due to the connectors and PCB traces.
10.3 Equipment Shutdown
1. Reduce the load current to 0 A.
2. Reduce input voltage to 0 V.
3. Shut down the external fan if in use.
4. Shut down equipment.
Test Procedure www.ti.com
12 TPS549D22 SWIFT™ Step-Down Converter Evaluation Module User's Guide SLUUBG4A – JULY 2016 – REVISED AUGUST 2021
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