Automotive battery switch provides very low resistance at high currents

October 22, 2013 // By Christoph Hammerschmidt
Chipmaker Infineon and PCB design and manufacturing company Schweizer Electronic AG have developed a demonstrator of an electronic high-performance battery switch for automotive applications. The device shows how entire battery circuits or subnets can be controlled at minimum space requirements. The switch copes with currents of 400A continuous current or 7,200A current pulses.

Core elements of the electronic battery switch are the latest generation MOSFETs from Infineon. They feature a leadless TO package and 40V OptiMOS semiconductor technology. Schweizer contributes its Inlay PCB technology with 2 mm heavy copper inlays for maximum current carrying capability and heat dissipation.

Typical applications are replacements for today's widespread pyro-electric solutions, switching of high-current loads or battery power supplies in vehicles during driving operations as well as when parking. Electronic switching solutions also can prevent electromigration and corrosion of electronic components, and optimise quiescent currents.

In the device, Infineon IPLU300N04S4-R7 MOSFETs are used, with minimum on-resistance of just 84 µOhms. They also are designed for a maximum current carrying capability of 300A and best possible heat dissipation of 0.35 K/W. Despite the improved performance, the footprint is reduced by 30% in comparison to the D2PAK. The semiconductor features are complemented by Schweizer's assembly technology which achieves a total resistance from clamp to clamp of only 113 µOhms. This allows  very compact, efficient and robust high-current solutions, which in the past have not been possible to implement for cost or technical reasons, the companies said.