Freescale MCUs simplify car wiring system, cut vehicle weight

March 20, 2013 // By Christoph Hammerschmidt
The second-heaviest component of a modern car - after the engine - is the cable loom. New applications raise the demand for more bandwidth, more connectivity - and even more wires within the car. With a new range of microcontrollers for body applications, Freescale promises to enable designers to reduce this weight. The approach: higher functional integration will reduce the need to send signals across the body of the car.

The growing number of electronic control units (ECUs) in cars causes the complexity of the wiring system to grow accordingly. In an average passenger car, the infrastructure for data and signal transport embraces copper wires with a total length of several kilometres. The weight of these cable looms easily exceeds 70 kilograms, the weight of an adult man. Weight, in turn translates into fuel consumption and cost. The weight of these wiring systems can significantly be reduced if more functions are integrated into less ECUs. For years, major OEMs are calling for a reduction in the ECU count. A "domain controller" could assume the functionality of several disperse single-function ECUs, effectively reducing the overall weight of the vehicle and along with the weight the fuel consumption.

Besides the demand for more "green" cars, there is a rising demand for functional safety, defined by the ISO26262 standard. This demand includes the design of safety-relevant functions such as exterior light and windscreen wipers.

Freescale has customized the new Qorivva MPC5748G and S12 MagniV S12VL/S12ZVC MCUs to meet this demand. They complement the central Qorivva Controller which with centralized functions for data privacy and security, intelligent power management and ASIL support for functional safety assumes the functions of a gate keeper for the internal data network. The S12 MagniV satellite nodes are equipped with an integrated power supply on their mixed-signal MCU. The extreme degree of integration offered by these components can significantly contribute to simplify the power and data network in the vehicle. Up to 10 kilograms less weight is what Freescale promises in this context, yielding better efficiency in the manufacturing process and up to 30 % smaller PCBs.

The Qorivva MPC5748G MCU is a single-chip solution for next-generation central body control and gateway applications. It combines a high level of integration with low-power management modes, support for functional safety and robust security features.

Fig 1: Qorivva MPC5748G Block diagram. For