L6668 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
'L6668' PDF : 23 Pages View PDF
L6668
Figure 43 shows a timing diagram where the PFC_STOP function operation is illustrated under different
operating conditions.
Figure 42. How the L6668 can switch off a PFC controller at light load
Vcc
16
L6668
BC557
10 kΩ
14 PFC_STOP
8.2 V
2.2 kΩ
Vcc
PFC
controller
Figure 43. Operation of PFC_STOP function
Vcc
VccON
VccOFF
PFC_STOP
t
COMP
OUT
t
2.2V
2.7V
t
PFC
Gate
Drive
Start-up
Full-load
Light-load
t
Full-load
t
Figure 44. Operation after DIS pin activation: timing diagram
DIS
2.2V
Vcc
VccON
VccON -0.5
VccOFF
Vccrest
OUT
Vin
VHVstart
HV generator is turned on
t
Disable latch is reset here
HV generator is disabled here
t
Input source is removed here
t
t
18/23
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