Texas Instruments UCC28610EVM-474, User Manual

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Test Procedure
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6.3 Output Voltage Regulation and Efficiency
1. For load regulation:
(a) Use the test set up shown in Figure 4 .
(i) Be sure to remove the external shunt from the power analyzer and set the analyzer to normal
mode (not long averaging).
(b) Set the AC source to a constant voltage between 85 V
AC
and 265 V
AC
.
(c) Apply power to the EVM per Section 6.1 .
(d) Vary the load current from 0 A up to 2.1 A, as measured on DMM A
1
.
(e) Observe that the output voltage on DMM V
1
remains within 10% of 12 V
DC
.
2. For line regulation:
(a) Set the load to sink 2.1 A.
(b) Vary the AC source from 85 V
AC
to 265 V
AC
.
(c) Observe that the output voltage on DMM V
1
remains within 10% of 12 V
DC
.
3. Make sure the input power is off and the bulk capacitor and output capacitors are completely
discharged before handling the EVM.
6.4 Output Voltage Ripple
1. Expose the ground barrel of the scope probe. Insert the tip of the probe into the plated via located on
the +Vout pad of the EVM (TP1) and lean the probe so that the exposed ground barrel is resting on the
test point on the
– Vout pad of the EVM (TP2) for a tip and barrel measurement as shown in the
example depicted in Figure 5 .
2. Apply power to the EVM per Section 6.1 .
3. Monitor the output voltage ripple on the oscilloscope.
Figure 5. Typical Example of Tip and Barrel Measurement Technique
NOTE: This photo was not taken on the UCC28610EVM specifically but serves as a visual aid to
perform the test measurement.
6.5 Equipment Shutdown
1. Ensure the load is at maximum; this will quickly discharge the output capacitors.
2. Turn off the AC source.
12 UCC28610EVM-474 25-W Universal Off-Line Flyback Converter SLUU383B – November 2009 – Revised May 2011
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