L6564 STMicroelectronics, L6564 Datasheet - Page 21

• Manufacturer Part Number: L6564
• Description: 10 pin transition-mode PFC controller
• Manufacturer: STMicroelectronics

L6564
The twice-mains-frequency (2
peak amplitude that, with good approximation, is given by:
where f
ripple, related to the amplitude of its 2
Figure 29
amount of maximum desired 3rd harmonic distortion. Note that there is a minimum value for
the time constant R
occur. In fact, the twice-mains-frequency ripple across C
must be lower than the minimum line drop detection threshold (ΔV
Therefore:
Always connect RFF and CFF to the pin, the IC will not work properly if the pin is either left
floating or connected directly to ground.
Figure 29. R
R
FF
· C
L
FF
is the line frequency. The amount of 3rd harmonic distortion introduced by this
shows a diagram that helps choose the time constant R
[s]
current
0.01
FF
0.1
10
1
·C
0.1
FF
FF
as a function of 3rd harmonic distortion introduced in the input
· C
FF
below which improper activation of the VFF fast discharge may
•
Doc ID 16202 Rev 4
f
L
R
) ripple appearing across C
FF
f = 60 Hz
Δ
⋅
L
D
C
V
3
•
FF
FF
f
%
L
component, will be:
>
=
=
1
2
2
D %
+
V
2
π
3
1
Δ
f 4
MULTpk
V
f
L
V
100
L
MULTpk
R
f 4
VFF
R
FF
L
FF
f = 50 Hz
_
L
C
_
C
min
_
min
FF
max
FF
FF
−
1
under steady state conditions
FF
is triangular with a peak-to-
FF
FF_min
Application information
·C
FF
= 40 mV).
10
based on the
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