Ideal diode controllers protect reverse connections and voltage transients

Diodes Incorporated has introduced the AP74502Q and AP74502HQ automotive-compliant 80V ideal diode controllers, delivering robust and reliable protection against reverse connections and voltage transients. Typical applications include ADAS, body control modules, infotainment systems, exterior lighting, and USB charging ports.

The ideal diode controllers have all the features required to implement an efficient and fast reverse polarity protection circuit. They also feature a load disconnect function in the event of overvoltage and undervoltage conditions. With an 80V capability, they are ideal for all 12V and 24V batteries. This includes batteries in hybrid and battery EVs, as well as the emerging 48V systems.

The shift to 48V is paving the way for EV innovations, allowing features like electric turbocharging and improved regenerative braking. The higher voltage also facilitates advanced infotainment systems and electrified auxiliary components. It could also lead to a zonal architecture, allowing for more efficient power distribution and reduced wiring requirements. The ±80V rating is particularly relevant for the stricter overvoltage stress conditions associated with these 48V systems.

Unlike ideal diodes with reverse current blocking features, these devices are appropriate for applications where energy may return to the input supply. However, they can also be configured as surge stoppers to protect overvoltage supply and downstream loads against unsuppressed load dump transients.

The controllers also support input voltages as low as 3.2V, assuring correct and reliable operation even during severe cold crank conditions, which can cause the battery voltage to drop significantly. Both devices share a peak gate turn-off sink current of 2.3A, allowing rapid turn-off of the external N-channel MOSFETs when needed, for example, during overvoltage or undervoltage events.

When the charge pump is enabled, the operating quiescent current (IQ) is 62µA, and 1µA in disabled mode. This minimises the overall power consumption of the system and decreases battery drain to an absolute minimum.

The AP74502Q features a peak gate source current of typically 60 μA, which provides a smooth start-up with inherent inrush current control. This is advantageous in applications where limiting the initial current surge is important. In contrast, the AP74502HQ provides a higher 11mA peak gate source current, similar to earlier members of the company’s ideal diode controller portfolio. This stronger gate drive enables a faster turn-on of the external MOSFET, within 1µs (typ.).

The AP74502Q and AP74502HQ are obtainable in the industry-standard SOT28 package with an operating temperature range from -40C to +125C.