NCP1246 ONSEMI [ON Semiconductor], NCP1246 Datasheet - Page 24

• Manufacturer Part Number: NCP1246
• Description: Fixed Frequency Current Mode Controller for Flyback Converters
• Manufacturer: ONSEMI [ON Semiconductor]

The Low Consumption Off Mode
allowing to reach extremely low no load input power as
described in previous chapters. If the voltage at feedback pin
decreases below the 0.4 V the controller enters the off mode.
The internal V
low V
capacitor is maintained by the SelfïSupply circuit. The
SelfïSupply circuit keeps the V
level. The supply for the FB pin watch dog circuitry and FB
pin bias is provided via the low consumption current sources
from the external V
start, if the FB pin voltage increases above the 2.2 V level.
See Figure 55 for timing diagrams.
There was implemented the low consumption off mode
Figure 54. HV Pin ac Input Timing Diagram with X2 Capacitor Discharge Sequence When the Application is
CC
current and only the voltage at external V
CC
is turnedïoff, the IC consumes extremely
CC
capacitor. The controller can only
CC
voltage at the V
Unplugged Under High Line Condition
http://onsemi.com
CC(reg)
CC
NCP1246
24
enabled in the low consumption off mode. The X2 cap
discharging feature is enable due the safety reasons and the
SelfïSupply is enabled to keep the V
very low V
features are disabled in this mode.
in the low consumption off mode and this mode is used for
the TSD protection as well. The protection timer
GoToOffMode t
against the false activation of the low consumption off mode
by the fast drop outs of the FB pin voltage below the 0.4 V
level. E.g. in case when is present high FB pin voltage ripple
during the skip mode.
Only the X2 cap discharge and SelfïSupply features is
The information about the latch status of the device is kept
CC
consumption appears in this mode. Any other
GTOM
is used to protect the application
CC
supply, but only