Semiconductor switches replace fuses, relays

Semiconductor switches replace fuses, relays

New Products |
By Jean-Pierre Joosting

Today, relays and fuses impede the evolution of power distribution networks in vehicles. Both types of components however use lots of space, needs relatively frequent replacement and offer only limited functionality, with an operating life expectancy of some 200.000 switching cycles.

Infineon’s new Power PROFETs, in contrast enable replacement of electromechanical relays and fuses in power distribution and junction boxes up to 40A DC as a first step to introduce smart, decentralized distribution networks. Featuring the lowest on-resistance on the market, the Power PROFET switches offer benefits such as superior switching cycle capability with more than one million switching cycles.

Also, they replace within one single device multiple components from the existing system, such as relays, fuses, relay drivers, cables and connectors. This allows new mounting locations and, therefore, enables the next generation of decentralized power architectures.

The Power PROFET switches feature on-resistances down to 1.0mΩ and are designed to drive high-current applications. These comprise power feeds of electronic control units (ECUs), auxiliary power outlets, PTC heaters or rear window heaters. The switches are also suited for applications with high switching cycles and high energy requirements such as starter relays in start-stop systems and electric brake vacuum pumps. Power PROFET switches also offer integrated protection functions and diagnostics functionality including, short circuit protection and over-temperature protection.

POwer PROFET switches increase energy efficiency as power losses are reduced by a factor of up to 7. They feature less than 2W dissipation while conducting 30A DC. Further power management is supported through integrated current sensing and pulse-width modulation capability. In addition, the semiconductor switches offer a benchmark energy handling capability of up to 3,000mJ for single pulses and 550mJ for repetitive pulses. For most applications, this eliminates the need for a free-wheeling current recirculation path and thus reduces the system cost.

The switches provide a protection performance of more than 1,000,000 short-circuit cycles, achieving Grade A according to AEC-Q100. In case of a single over-current event, a re-start strategy can be implemented via a software reset. Thus, there is no need to access or replace a part any longer. At the system level, Power PROFET switches enable a more accurate system sizing. Also, they simplify significantly the wire harness architecture by reducing the lengths of many wires or removing them completely.

Today, the Power PROFET family consists of four pin-compatible switches controlling currents from 20A to 40A DC. Their on-state resistance R DS(ON) scales with 1.0mΩ, 1.5mΩ, 2.0mΩ, or 2.5mΩ for each device. The two lowest ohmic devices of the family, the BTS50010-TAD with 1.0mΩ and the BTS50015-1TAD with 1.5mΩ, are already available for high-volume. Further Power PROFET switches start mass production in early 2017.

To support design activities, Infineon provides a Power PROFET evaluation board. Evaluation software, user’s manual, application notes and further information are available at

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