AP74502Q Ideal Diode Controller Tackles Reverse Polarity and Overvoltage in 48V Automotive Systems
Keeping modern automotive electronics safe from power faults is harder than it looks. With today’s vehicles running everything from ADAS to infotainment off shared battery rails, even brief overvoltage spikes or polarity reversals can put sensitive loads at risk. Enter Diodes Incorporated, which has just introduced two new ideal diode controllers, the AP74502Q and AP74502HQ, designed specifically for automotive-grade reverse polarity and overvoltage protection.
Designed for Harsh Power Rails
Both devices are built to handle the reality of automotive power systems, supporting inputs from 3.2V all the way up to 75V, with an absolute max rating of 80V. That means they’re suitable not only for legacy 12V and 24V systems, but also for the emerging 48V topologies now common in EVs and hybrids.
What makes that 3.2V floor particularly useful is cold crank tolerance. During engine start in low temperatures, voltages can sag far below nominal, and any protection circuitry that drops out during that dip can become the failure point itself. Diodes’ low-end spec helps sidestep that issue entirely.
External FET Drive with Tunable Inrush
The AP74502 family drives back-to-back external N-channel MOSFETs, allowing designers to fully isolate downstream circuits when faults occur. Both variants also feature overvoltage lockout (OVLO), which can be set via external resistors to disconnect the load when VIN exceeds safe limits.
Where they differ is in gate drive strength:
- The AP74502Q offers a 60μA gate source current, turning on the FETs more gradually to help limit inrush current.
- The AP74502HQ delivers a faster 11mA peak, ideal when turn-on time is more critical than soft-start behaviour.
That flexibility gives engineers some wiggle room to match protection performance to system needs, whether that’s soft-starting a high-capacitance load or reacting quickly to transient conditions.
No Blocking, No Problem
One detail that stands out is the absence of reverse current blocking. These parts aren’t designed to prevent current from flowing back into the supply rail. In most applications, that’s not a drawback; in fact, it’s exactly what you want when dealing with inductive loads, like motors or actuators, that can return energy to the input during braking or sudden stops.
Think body control modules, exterior lighting, or ADAS sensors, all scenarios where loads might generate their own back EMF. Rather than fighting that, the AP74502 lets it pass, while still keeping polarity and overvoltage faults at bay.
Automotive-Ready and Built to Last
Naturally, both variants are AEC-Q100 Grade 1 qualified, rated for operation from -40°C to +125°C, and housed in the familiar SOT28 package. They’re manufactured at IATF 16949 certified sites, with full PPAP documentation available, so there’s nothing stopping engineers from slotting these directly into automotive designs.
All told, the AP74502 family gives designers a compact, low-IQ, and cost-effective way to improve power resilience in increasingly demanding automotive systems.
Compare Pricing and Availability
Looking to source the AP74502Q or AP74502HQ? Use the link below to instantly compare real-time pricing, inventory, and lead times from authorised distributors via oemsecrets.com.
Learn more and read the original article on www.diodes.com
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