STMicroelectronics L6563H 100 W TM PFC demonstration board EVL6563H-100W EVL6563H-100W Fiche De Données
Codes de produits
EVL6563H-100W
AN3063
EMI filtering and conducted EMI pre-compliance measurements
Doc ID 16261 Rev 3
27/33
6
EMI filtering and conducted EMI pre-compliance
measurements
measurements
The following figures show the peak measurement of the conducted noise at full load and
nominal mains voltages for both mains lines. The limits shown in the diagrams are EN55022
class-B which is the most popular regulation for domestic equipment using a two-wire mains
connection.
nominal mains voltages for both mains lines. The limits shown in the diagrams are EN55022
class-B which is the most popular regulation for domestic equipment using a two-wire mains
connection.
It is also useful to remind that typically a PFC produces a significant differential mode noise
with respect to other topologies and therefore in case an additional margin with respect to
the limits is required, we suggest trying to increase the across-the-line (X) capacitors or the
capacitor after the rectifier bridge C5. This will be more effective and cheaper than
increasing the size of the common
with respect to other topologies and therefore in case an additional margin with respect to
the limits is required, we suggest trying to increase the across-the-line (X) capacitors or the
capacitor after the rectifier bridge C5. This will be more effective and cheaper than
increasing the size of the common
-
mode filter coil that would filter the differential mode
noise by the leakage inductance between the two windings only.
In order to recognize if the circuit is affected by common mode or differential mode noise, it
is sufficient to compare the spectrum of phase and neutral line measurements. If the two
measurements are very similar, the noise is almost totally common mode. If there is a
significant difference between the two measurement spectrums, their difference represents
the amount of differential mode noise. Of course to get a reliable comparison the two
measurements have to be done in the same conditions. If the peak measurement is used as
in the figures below, some countermeasures will have to be used, like synchronizing the
sweep of the spectrum analyzer with the input voltage. This is necessary with TM PFC
having a switching frequency that is modulated along the sine wave.
is sufficient to compare the spectrum of phase and neutral line measurements. If the two
measurements are very similar, the noise is almost totally common mode. If there is a
significant difference between the two measurement spectrums, their difference represents
the amount of differential mode noise. Of course to get a reliable comparison the two
measurements have to be done in the same conditions. If the peak measurement is used as
in the figures below, some countermeasures will have to be used, like synchronizing the
sweep of the spectrum analyzer with the input voltage. This is necessary with TM PFC
having a switching frequency that is modulated along the sine wave.
Because the differential mode produces the common mode noise by the magnetic field
induced by the current, decreasing the differential mode consequently limits the second one.
induced by the current, decreasing the differential mode consequently limits the second one.
Figure 36.
EVL6563H-100W CE peak
measurement at 100 Vac, 50 Hz, full
load phase
measurement at 100 Vac, 50 Hz, full
load phase
Figure 37.
EVL6563H-100W CE peak
measurement at 100 Vac, 50 Hz, full
load, neutral
measurement at 100 Vac, 50 Hz, full
load, neutral
!-V
!-V