Semiconductor switches replace fuses, relays

November 04, 2016 // By Christoph Hammerschmidt
Cable harnesses are cumbersome components for automotive electronics designers. Heavy, clumsy and expensive, they withstand all attempts to improve and develop them. With the Power PROFET switches, Infineon makes a start towards space-saving, cost-efficient cable harnesses.

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.