L6561_04 STMICROELECTRONICS [STMicroelectronics], L6561_04 Datasheet - Page 4
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L6561_04
Manufacturer Part Number
L6561_04
Description
POWER FACTOR CORRECTOR
Manufacturer
STMICROELECTRONICS [STMicroelectronics]
Datasheet
1.L6561_04.pdf
(13 pages)
Table 5. Electrical Characteristics (continued)
(V
L6561
3
The output voltage is expected to be kept by the operation of the PFC circuit close to its nominal value.
This is set by the ratio of the two external resistors R1 and R2 (see fig. 5), taking into consideration that
the non inverting input of the error amplifier is biased inside the L6561 at 2.5V.
In steady state conditions, the current through R1 and R2 is:
and, if the external compensation network is made only with a capacitor C
equals zero.When the output voltage increases abruptly the current through R1 becomes:
Since the current through R2 does not change, I
error amplifier.
This current is monitored inside the L6561 and when reaches about 37 A the output voltage of the multi-
plier is forced to decrease, thus reducing the energy drawn from the mains. If the current exceeds 40 A,
the OVP protection is triggered (Dynamic OVP), and the external power transistor is switched off until the
current falls approximately below 10 A.
However, if the overvoltage persists, an internal comparator (Static OVP) confirms the OVP condition
keeping the external power switch turned off (see fig. 4).Finally, the overvoltage that triggers the OVP
function is:
Typical values for R
4/13
OUTPUT SECTION
OUTPUT OVERVOLTAGE SECTION
RESTART TIMER
Symbol
t
CC
I
V
START
V
GD off
I
I
I
I
I
V
ZCD
ZCD
ZCD
ZCD
OVP
ZCD
DIS
GD
t
t
r
f
OVER VOLTAGE PROTECTION OVP
= 14.5V; T
Pin
5
5
5
5
5
5
7
7
7
7
2
amb
Lower Clamp Voltage
Sink Bias Current
Source Current Capability
Sink Current Capability
Disable threshold
Restart Current After Disable
Dropout Voltage
Output Voltage Rise Time
Output Voltage Fall Time
IGD Sink Current
OVP Triggering Current
Static OVP Threshold
Start Timer
= -25°C to 125°C;unless otherwise specified)
1
, R
2
Parameter
and C are shown in the application circuits. The overvoltage can be set indepen-
I
R1
=
I
R1sc
V
---------------------------------------------------- -
outsc
=
V
------------------------- -
V
+
I
1V
V
I
I
I
I
C
C
V
ZCD
GDsource
GDsource
GDsink
GDsink
out
ZCD
CC
out
L
L
R1
R1
= 1nF
= 1nF
V
=3.5V V
= -3mA
–
= R
V
out
< V
R1
ZCD
= 200mA
= 20mA
2.5
Test Condition
= 200mA
= 20mA
must flow through the capacitor C
dis
1
–
· 40 A.
; V
2.5
=
4.5V
GD
CC
I
R2
= 1V
=
> V
I
=
R1sc
CCOFF
2.5V
------------
R2
+
I
R1
comp
Min.
-100
150
0.3
2.1
35
70
-3
3
5
, the current through C
-200
Typ.
0.65
2.25
200
150
1.2
0.7
40
40
10
40
2
comp
Max.
-300
250
100
100
400
-10
and enter the
1.5
0.3
2.4
10
45
1
2
1
-
Unit
mA
mA
mV
mA
ns
ns
V
V
V
V
V
V
comp
A
A
A
s