EN63A0QI
power FETs are turned off for the rest of the
switching cycle. If the over-current condition is
removed, the over-current protection circuit will re-
enable PWM operation. If the over-current condition
persists, the circuit will continue to protect the load.
The OCP trip point is nominally set as specified in
the Electrical Characteristics table. In the event the
OCP circuit trips consistently in normal operation,
the device enters a hiccup mode. The device is
disabled for 27µs and restarted with a normal soft-
start. This cycle can continue indefinitely as long as
the over current condition persists.
exceeds approximately 150ºC. Once the junction
temperature drops by approx 20ºC, the converter
will re-start with a normal soft-start.
Input Under-Voltage Lock-Out
When the input voltage is below a required voltage
level (VUVHI) for normal operation, the converter
switching is inhibited. The lock-out threshold has
hysteresis to prevent chatter. Thus when the device
is operating normally, the input voltage has to fall
below the lower threshold (VUVLO) for the device to
stop switching.
Thermal Overload Protection
Temperature sensing circuits in the controller will
disable operation when the junction temperature
Enpirion 2012 all rights reserved, E&OE
Enpirion Confidential
www.enpirion.com, Page 16
07077
May 9, 2012
Rev: C
ENPIRION [ ENPIRION, INC. ]
