Datasheet

L6699 Line sensing function
Doc ID 022835 Rev 2 31/38
Figure 22. Line sensing function: internal block diagram and timing diagram
While the line undervoltage is active there is no switching activity, therefore the V
CC
voltage
(if not supplied by another source) continuously oscillates between the startup and the
UVLO thresholds, as shown in the timing diagram of
Figure 22 .
The LINE pin, while the device is operating, is a high impedance input connected to high
value resistors, so it is prone to pick-up noise,. This might alter Vin
OFF
or give rise to
undesired switch-off of the IC during ESD tests. It is possible to bypass the pin to ground
with a small film capacitor (e.g. 1-10 nF) to prevent any malfunctioning of this kind.
If the function is not used the pin can be pulled high by connecting it to V
CC
through a
resistor in the hundred k
Ω.
!-V
(6)NPUTBUS
6IN /+
6CC
6IN
/.
6IN
/&&
,6'
(6'
6OUT
,).%
6
)
(93
!
T
T
T
T
T
T
T


,
6IN/+
(6)NP UTBU S
6
,).%
6CC


6
!
2
(
2
,