L6668 Datasheet, PDF (4/23 Pages) STMicroelectronics – SMART PRIMARY CONTROLLER

L6668
Table 4. Pin Description (continued)
Pin
Number
13
14
15
16
Pin Name
Function
STBY
PFC_STOP
S-COMP
RCT
Standby function. This pin is a high-impedance one as long as the voltage on pin COMP is
higher than 3V. When the voltage on pin COMP falls below 3V, the voltage on the pin tracks
that on pin COMP and is capable of sinking current. A resistor connected from the pin to the
oscillator allows programming frequency foldback at light load.
Open-drain ON/OFF control of PFC controller. This pin is intended for driving the base of a
PNP transistor in systems comprising a PFC pre-regulator, to stop the PFC controller at
light load by cutting its supply. The pin, normally low, opens if the voltage on COMP is lower
than 2.2V and goes back low when the voltage on pin COMP exceeds 2.7V. Whenever the
IC is shutdown, either latched (DIS>1.5V, ISEN >1.5V) or not (UVLO, SKIPADJ<0.8), the
pin is open as well.
Voltage ramp for slope compensation. When the gate-drive output is high the pin delivers a
voltage tracking the oscillator ramp (shifted down by one V_BE); when the gate-drive output
is low the voltage delivered is zero. The pin is to be connected to pin ISEN via a resistor to
make slope compensation and allow stable operation at duty cycles close to and greater
than 50%.
Oscillator pin. A resistor to VREF and a capacitor to GND define the oscillator frequency (at
full load). A resistor connect to STBY modifies the oscillator frequency when the voltage on
pin COMP is lower than 3V.
Table 5. Electrical Characteristcs
(T_j = 0 to 105°C, Vcc=15V, Co=1nF; R_T =13.3k , C_T =1nF; unless otherwise specified)
Symbol
Parameter
SUPPLY VOLTAGE
Vcc Operating range
V_CCOn
V_CCOff
Turn-on threshold
Turn-off threshold
Hys Hysteresis
V_Z
Zener Voltage
SUPPLY CURRENT
I_start-up Start-up Current
I_q
Quiescent Current
I_CC
Operating Supply Current
I_qdis Shutdown quiescent
current
HIGH-VOLTAGE START-UP GENERATOR
V_HV Breakdown voltage
V_HVstart Start voltage
I_charge Vcc charge current
I_{HV, ON} ON-state current
I_{HV, OFF} Leakage current (OFF state)
V_CCrestart HV generator restart voltage
Test Condition
After turn-on
(1)
(1) _{After turn-on}
Icc = 20 mA
Before turn-on,
Vcc=Vcc_ON-0.5
After turn-on
V_DIS > 2.2, or V_ISEN > 1.5
V_SKIPADJ<0.8
0.8 <V_COMP < V_SKIPADJ
I_HV < 100 µA
I_Vcc < 100 µA
V_HV > V_Hvstart, Vcc > 3V
V_HV > V_Hvstart, Vcc > 3V
V_HV > V_Hvstart, Vcc = 0
V_HV = 400 V
(1) _{After DIS tripping}
Min. Typ. Max. Unit
9.4
22
V
12.5 13.5 14.5
V
8.0
8.7
9.4
V
4.0
V
22
24
28
V
150
µA
2
2.5
mA
4
mA
180
µA
1
1.8
mA
1.3
mA
700
V
50
80
110
V
0.55 0.85
1
mA
1.6
mA
0.8
40
µA
4.4
5
5.6
V
12
13
14
V
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