Texas Instruments TPS548D21EVM-784, Руководство пользователя

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Test Procedure
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8 SLUUBG3A – July 2016 – Revised August 2016
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Copyright © 2016, Texas Instruments Incorporated
TPS548D21EVM-784, 40-A Single Synchronous Step-Down Converter With
Full Differential Sense
8 Test Procedure
8.1 Line and Load Regulation Measurement Procedure
1. Connect VOUT to J3 and VOUT_GND to J5 Figure 2 .
2. Ensure that the electronic load is set to draw 0 A
DC
.
3. Ensure the jumper provided on the EVM shorts on J4 before V
IN
is applied
4. Connect VIN to J1 and VIN_GND to J2 Figure 2 .
5. Increase V
IN
from 0 V to 12 V using the digital multimeter to measure input voltage.
6. Connect the external voltage source to TP14. Note: Make sure the external source is noise free.
7. Increase the external voltage source from 0 V to 0.9 V.
8. Remove the jumper on J4 to enable the controller.
9. Use the other digital multimeter or the oscilloscope to measure output voltage V
OUT
at TP2 and TP10.
Table 3. 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
10. Vary the load from 0 A
DC
to maximum rated output 40 A
DC
. V
OUT
must remain in regulation as defined
in Table 1 .
11. Vary V
IN
from 5 V to 16 V. V
OUT
must remain in regulation as defined in Table 1 .
12. Decrease the load to 0 A.
13. Put the jumper back on J4 to disable the converter.
14. Decrease V
IN
to 0 V or turn off the supply.
15. Decrease the external voltage source to 0 V, or turn off the supply.
8.2 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 4. 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.