Smart power switch family with low ohmic resistance optimises auto power distribution

As vehicle architectures transition to HEVs and EV models, conventional battery systems are increasingly being supplemented or replaced by 48V power sources. This shift is expected to become the new standard for future EVs as 12V and 24V power net systems reach their limits. 48V systems allow advanced features, enhance passenger comfort, and enhance efficiency by lowering currents and simplifying wire harness complexity. Also, the electrification of primary and secondary power distribution systems needs replacing conventional relays and fuses. Infineon Technologies AG is launching the Power PROFET + 24/48V switch family, which is developed for modern vehicle power systems to support this development.

This switch family is housed in a compact, TO leadless package and includes two high-side switch variants: the BTH50030-1LUA with an R DS(ON) of 3mOhm and the BTH50015-1LUA with an R DS(ON) of 1.5mOhm, which allows minimal power losses in high-current applications. The devices are excellent for the demanding requirements of today's automotive electrical systems and for commercial and hybrid vehicles, and the next generation of EVs, where they facilitate a safer, greener and more comfortable driving experience.

One of the key benefits of the switch family is its efficiency and space-saving capabilities. The switches are highly integrated and provide resettable and diagnostic features. They are developed for optimal performance in demanding environments and deliver a low on-resistance of just 1.5mOhm. This makes them ideal for high-current applications and robust enough to withstand the conditions in hot cabin and engine compartments. With more than 1,000,000 switching cycles, the switches far exceed the average 200,000 cycles of conventional relays and deliver excellent reliability.

Built-in protection and diagnostic functions such as short-circuit, over-current, and over-temperature protection ensure the device's safety. Diagnostic signals allow advanced fault detection and improve the reliability of the entire vehicle by preventing failure modes in the power supply network. The switches are housed in an 8-pin TO leadless package, decreasing the footprint by 23% compared to, for example, D2PAK packages with similar thermal performance. The accuracy of the load current sense is ±5% after calibration and can be readily determined by reading an analog voltage at the IS pin. In addition, the switch family is PRO-SIL ISO switch 26262-ready and comes with a safety application note that supports the evaluation of hardware elements according to ISO 26262.

To enable seamless integration, the Power PROFET + 24/48V family is supported by the online simulation tool Infineon Automotive Power Explorer, which is obtainable in the Infineon Developer Center. The tool helps to calculate intrinsic fuse characteristics and visualise the sense current range for specific load currents, ensuring accurate and efficient implementation.