E-L6561D013TR Datasheet, PDF (4/13 Pages) STMicroelectronics – POWER FACTOR CORRECTOR

L6561
Table 5. Electrical Characteristics (continued)
(V_CC = 14.5V; T_amb = -25°C to 125°C;unless otherwise specified)
Symbol Pin
Parameter
V_ZCD
5 Lower Clamp Voltage
I_ZCD
5 Sink Bias Current
I_ZCD
5 Source Current Capability
I_ZCD
5 Sink Current Capability
V_DIS
5 Disable threshold
I_ZCD
5 Restart Current After Disable
OUTPUT SECTION
V_GD
7 Dropout Voltage
t_r
7 Output Voltage Rise Time
t_f
7 Output Voltage Fall Time
I_{GD off} 7 IGD Sink Current
OUTPUT OVERVOLTAGE SECTION
I_OVP
2 OVP Triggering Current
Static OVP Threshold
RESTART TIMER
t_START
Start Timer
Test Condition
I_ZCD = -3mA
1V ≤ V_ZCD ≤ 4.5V
V_ZCD < V_dis; V_CC > V_CCOFF
I_GDsource = 200mA
I_GDsource = 20mA
I_GDsink = 200mA
I_GDsink = 20mA
C_L = 1nF
C_L = 1nF
V_CC =3.5V V_GD = 1V
Min. Typ. Max. Unit
0.3 0.65
1
V
2
µA
-3
-10
mA
3
10
mA
150 200 250 mV
-100 -200 -300 µA
1.2
2
V
0.7
1
V
1.5
V
0.3
V
40
100
ns
40
100
ns
5
10
-
mA
35
40
45
µA
2.1 2.25 2.4
V
70
150 400
µs
3 OVER VOLTAGE PROTECTION OVP
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:
I_R1sc
=
V_{-----o---u---t---–----}2_----._-5_--
R1
=
I_R2
=
2_----._-5_----V_---
R2
and, if the external compensation network is made only with a capacitor C_comp, the current through C_comp
equals zero.When the output voltage increases abruptly the current through R1 becomes:
I_R1
=
V_{-----o---u---t--s--c----+-----}∆_----V_{----o---u---t---–-----}2_---._--5_-
R1
=
I_R1sc + ∆I_R1
Since the current through R2 does not change, ∆I_R1 must flow through the capacitor C_comp and enter the
error amplifier.
This current is monitored inside the L6561 and when reaches about 37µA the output voltage of the multi-
plier is forced to decrease, thus reducing the energy drawn from the mains. If the current exceeds 40µA,
the OVP protection is triggered (Dynamic OVP), and the external power transistor is switched off until the
current falls approximately below 10µA.
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:
∆V_out = R₁ · 40µA.
Typical values for R₁, R₂ and C are shown in the application circuits. The overvoltage can be set indepen-
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