Zero-quiescent-current controller for reverse polarity protection

April 18, 2016 // By Graham Prophet
Texas Instruments is highlighting its LM74610-Q1, first announced late in 2015; a controller device that can be used with an N-Channel MOSFET in a reverse polarity protection circuitry. It is designed to drive an external MOSFET to emulate an ideal diode rectifier when connected in series with a power source. This scheme is not referenced to ground and thus has zero-Iq.


The LM74610-Q1 controller provides a gate drive for an external N-Channel MOSFET and a fast response-internal comparator to discharge the MOSFET Gate in the event of reverse polarity. This fast pull-down feature limits the amount and duration of reverse current flow if opposite polarity is sensed. The device design also meets CISPR25 Class 5 EMI specifications and automotive ISO7637 transient requirements with a suitable TVS diode.


Features include;

Qualified for automotive applications

AEC-Q100 qualified with the following results:

Exceeds HBM ESD classification level 2

Device CDM ESD classification level C4B

Maximum reverse voltage of 45V

No positive voltage limitation to anode terminal

Charge pump gate driver for external N-channel MOSFET

Lower power dissipation than Schottky diode/PFET solutions

Low reverse leakage current

Zero IQ

Fast 2 µsec response to reverse polarity

–40°C to 125°C operating ambient temperature

Can be used in OR-ing applications

Meets CISPR25 EMI specification

Meets automotive ISO7637 transient requirements with a suitable TVS diode


For automotive alternator and industrial power alternating current (AC) rectification, TI also has the LM74670-Q1 smart diode controller, which has higher gate drive current (70 µA) than the LM74610-Q1, allowing it to handle AC signals up to 300 Hz.

The device is accompanied by the LM74610-DQEVM evaluation module that demonstrates reverse polarity protection as a replacement of Schottky diodes and P-channel MOSFETs in a diode OR-ing configuration. In this reverse polarity protection solution two LM74610 Smart Diode Controllers are used to drive two 40V (VDS) external N-channel MOSFETs.