Smart power switch family for automotive applications

Since relays and fuses cannot fulfil the needs of modern E/E vehicle architectures, partial or complete electrification of the primary and secondary power distribution must be considered. Infineon Technologies AG has released a new generation of ultra-low ohmic high-side switches in a TO-leadless package, the Power PROFET + 12V switch family, to manage this issue.                                            

The switch permits new mounting locations and enclosure options, allowing the next generation of high-efficiency decentralised power architectures. Two variants are available: the BTS50005-1LUA with an on-resistance (R DS(ON)) of 0.6mOhm and the BTS50010-1LUA with an R DS(ON) of 1mOhm for lowest power losses. They are developed to control high-current applications, particularly in hot cabin and engine compartment environments for demanding high inrush currents, such as heaters, pumps and fans. They supply more than 1,000,000 switching cycles compared to, on average, 200,000 switching cycles of a relay.

The switches can replace electromechanical relays, fuses and discrete circuits in power distribution boxes and other applications up to 65A in a 12V electrical system. Also, the switches provide built-in protection and diagnostic functions, such as short-circuit, over-current and over-temperature protection. As a result, the devices are fully protected and supply a fault signal through the diagnosis, enabling the pin to a connected microcontroller for advanced diagnosis in power distribution modules. With their robustness, protection and diagnosis features, the switches enhance the reliability of the complete vehicle by stopping failure modes in the power board net.

The smart power switches are housed in an 8-pin TO leadless package, reducing the footprint by 23% compared to D2PAK while delivering similar thermal performance. The load current sense's accuracy has been improved to 5% and can be evaluated by reading an analog voltage on the IS pin. Also, the switch family is PRO-SIL ISO 26262-ready and arrives with a safety application note supporting the evaluation of hardware elements according to ISO 26262.

To provide an easy design-in process for these devices, the family is integrated into the company's Smart Power Switches Intrinsic Fuse Tool and the Smart Power Switches kILIS Tool, available in the Infineon Developer Center. The Smart Power Switches Intrinsic Fuse tool calculates the intrinsic fusing characteristic based on the embedded overtemperature protection of the selected product under certain boundary conditions. The kILIS tool is employed for calculating and visualising the range of the sense current for specific load currents on the respective selected product, considering the kILIS rate, sense resistor and ADC tolerances.