Datasheet

AN3180 A 200 W ripple-free input current PFC pre-regulator
Doc ID 17273 Rev 1 25/39
The waveforms of Figure 17 to 20 are taken at full load. The images in Figure 17 and 18
show the mains voltage and current drawn from the mains: this is quite sinusoidal, as in a
standard transition mode PFC converter. In fact its harmonic content is well below the
maximum allowed by current regulations (JEITA-MITI and European EN61000-3-2), as can
be seen from
Figure 14 and 15. Also the power factor and the total harmonic distortion
parameters are as good as for a standard circuit without the cancellation winding, as can be
seen from
Figure 16, where also the efficiency measurements are plotted, showing values
always greater than 91.7 %.
The zoomed image of
Figure 19 (@115 Vac) shows a residual ripple current in the DC
winding of 180 mA pk-pk, against a 6.053 A pk-pk of the AC winding current (which would
flow in the boost inductor in the conventional topology arrangement), and so resulting in
0.18/6.053 = 29.7*10-3 (-30.5 dB) attenuation.
Figure 17. Line current and voltage @ full load
(200 W) - Line current and voltage
@ 115 Vac -200 W
Figure 18. Line current and voltage @ full load
(200 W) - Line current and voltage
@ 230 Vac -200 W
Figure 19. AC and DC winding currents
nominal input voltages and full load
(200 W) - AC and DC winding
currents @ 115 Vac - 200 W
Figure 20. AC and DC winding currents
nominal input voltages and full load
(200 W) - AC and DC winding
currents @ 230 Vac - 200 W