NCP1560
Line Under/Over Voltage Shutdown
The NCP1560 incorporates a line under/over voltage
shutdown (UV/OV) circuit. The under voltage (UV)
threshold is 1.52 V and the over voltage threshold (OV) is
3.61 V, for a ratio of 1:2.4.
The UV/OV circuit can be biased using an external
resistor divider from the input line. The resistor divider must
be sized to enable the controller once Vin is within the
required operating range. If the UV or OV threshold is
reached, the soft start capacitor is discharged, and the
outputs are immediately disabled with no overlap delay as
shown in Figure 30. Also, if an UV condition is detected, the
5.0 V Reference Supply is disabled.
VAUX(on)
VAUX
VAUX(off)
0V
VOV
UV/OV Voltage
VUV
0V
UV or OV Fault
Propagation delay to
outputs (tUV or tOV)
OUT2
0V
OUT1
0V
Figure 30. UV/OV Fault Timing Diagram
http://onsemi.com
13