Automotive ideal diode controller with FET good open-drain output

The LM74703-Q1, LM74704-Q1 is an

automotive AEC Q100 qualified ideal diode controller which operates in conjunction

with an external N-channel MOSFET as an ideal diode rectifier for

low-loss

reverse polarity protection with a 20-mV forward voltage drop. The wide supply input

range of 3.2 V to 65 V allows control of

popular

DC bus voltages such as 12-V,

24-V,

and 48-V automotive battery systems. The 3.2-V input voltage support is

designed

especially for severe cold crank requirements in automotive

systems. The device can withstand and protect the loads from negative supply

voltages down to –65 V.

The device controls the gate of the

MOSFET to regulate the forward voltage drop at 20 mV. The regulation scheme enables

graceful turn off of the MOSFET during a reverse current event and

provides

zero DC reverse current flow. Fast response (< 0.75 µs) to

reverse

current

blocking

makes the device

applicable

for systems with output voltage holdup requirements during ISO7637 pulse testing as

well as power fail and input micro-short conditions. LM74703-Q1, LM74704-Q1 has

FETGOOD output to indicate external MOSFET drain to source short or open condition.

The device features enable pin (EN). With the enable pin low, the controller is off

and draws approximately

1-µA

of current.