DESCRIPTION
Demonstration circuit 2418A is intended to demonstrate
the performance of the LTC®4368 100V undervoltage (UV),
overvoltage (OV), and reverse protection controller with
bidirectional circuit breaker.
The LTC4368 protects circuits from overcurrent in both
directions and from input voltages that may be too high,
too low, or negative. The LTC4368 controls the gate voltage
of two back-to-back connected external MOSFETs to
ensure that the load is connected to the input supply only
when there are no voltage or current faults. The OV and
UV protection levels are adjusted by resistive dividers at
the OV and UV pins, respectively. Asserting a low signal
at the SHDN pin disables the MOSFETs and places the
controller in a low-current shutdown state. The FAULT pin
is asserted when the controller is in shutdown mode or
when the input voltage is outside of the UV or OV window,
or the load current exceeds the protection level, or the
input voltage is below undervoltage lockout (1.8V to 2.4V).
After a forward overcurrent fault, the LTC4368 will either
latch off power or retry after a user adjustable delay. A
reverse overcurrent fault waits for the output to fall 100mV
below the input to reconnect power to the load.
The LTC4368 can withstand DC voltages between –40V
and 100V and has an operating range of 2.5V to 60V.
The DC2418A includes the LTC4368 controller, two backto-
back connected power MOSFETs, current sense resistor,
three jumpers, and three LEDs to indicate the input and
output voltages and the FAULT pin signal.