Datasheet

Test results and significant waveforms AN2994
10/38 Doc ID 15796 Rev 2
The power factor (PF) and the total harmonic distortion (THD) have also been measured
and the results are reported in Figure 13 and Figure 14. As shown, the PF at full load and
half load remains close to unity throughout the input voltage mains range, while when the
circuit is delivering 70 W it decreases at a high mains range. THD is low, remaining within
20% at the maximum input voltage.
The converter’s efficiency reported in Figure 15 is very good at all load and line conditions.
At full load, it is always significantly higher than 90%, making this design suitable for high-
efficiency power supplies.
The measured output voltage variation at different line and load conditions is reported in
Figure 16. As shown, thanks to the voltage feed-forward function embedded in the L6563S,
the voltage is perfectly stable over the entire input voltage range. At 265 Vac and light load,
there is a negligible deviation of 1 V due to the intervention of the burst mode function.
Figure 11. EVL6563S-400W input current
waveform at 100 V, 60 Hz, 70 W load
Figure 12. EVL6563S-400W input current
waveform at 230 V, 50 Hz, 70 W load
CH1: Rectified mains voltage CH1: Rectified mains voltage
CH4: Input current CH4: Input current
Figure 13. Power factor vs. Vin and load Figure 14. THD vs. Vin and load
0.75
0. 8
0.85
0. 9
0.95
1
90 100 115 130 180 230 265
Vin [Vrms]
PF
400W
200W
70W
0
5
10
15
20
25
90 100 115 130 180 230 265
Vin [Vrms]
THD[%]
400W
200W
70W