Texas Instruments UCC28740EVM-525, User Manual

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SLUUAL8
e. Observe that if the constant resistance level of the electronic load is decreased lower than
the full load value, the EVM will maintain constant current regulation within 5% of the
programed value until the output voltge drops below 2 V. The EVM will automatically
restart once the constant resistance load is increased.
2. For line regulation, use the test set up shown in Figure 3
a. Set the constant resistance load to sink the full load current, approximately 2.38 Ω .
b. Vary the AC source from 85 V
AC
to 265 V
AC
c. Observe that the output voltage on DMM V
1
stays within 3% of the 5 V constant voltage
regulation value.
5.7 Output Voltage Ripple
1. Expose the ground barrel of the scope probe and place the tip of the probe on TP5, +VOUT,
and rest the exposed ground barrel of the probe on TP6, -VOUT, for output voltage ripple
measurements.
5.8 Equipment Shutdown
1. To quickly discharge the output capacitors, make sure there is a load greater than 0 A on the
EVM.
2. Turn off the AC source.