Solid-state smart junction box (S3JB) technology from Lear Corporation is said to offer dramatic improvements in volume, weight and cost as well as improved electrical system diagnostics and double failure-mode protection.
The technology, developed in partnership with STMicroelectronics and Smart Automotive System Engineering, provides power for power windows, power door locks, interior and exterior lighting, instrumentation, and the audio system.
Current smart junction box technology combines fuses, relays, a microcontroller and multiple interconnection layers in an integrated assembly. Combining Lear's connection systems with ST's solid-state drivers reduces junction box requirements from multiple printed circuit boards to one small board, reducing parts requirements and manufacturing complexity as well as size.
"The S3JB replaces relatively large fuses and relays with solid-state drivers," said Mohamad Zeidan, Lear’s manager of electrical distribution systems engineering. "This translates into a 50% to 80% reduction in volume, which allows greater packaging flexibility and optimization of the location because of the smaller size and elimination of the requirement for owner access, as well as a 40% to 70% reduction in weight and a 5% to 20% reduction in systems cost."
Joseph Notaro, director of market development for STMicroelectronics’ North American Automotive Business Unit, added that ST’s drivers contain proprietary technology that results in lower processor computational loads and more efficient electrical distribution system utilization. "Using this technology, we can achieve up to a 1 kg saving in the weight of copper in a vehicle,” Notaro said.