Electronic Design

Automotive Sensors Must Get Smart

In 1965, Gordon E. Moore published an article later coined "Moore's Law." Among other predictions, he hinted that digital devices could be used for automatic control in future automobiles.

Originally categorized as science fiction, the prediction has come to pass. The automotive industry has made significant strides toward enabling digital technologies in automotive applications, and it's aiming for the ultimate goal of the all-digital car.

Today, we have powerful signal processing in engine control. Each car has an average of more than 50 microcontrollers (MCUs). In-car networking protocols such as FlexRay, which will connect peripheral MCUs (located in the chassis, body, etc.), have been developed and adopted as well.

But to create this digital network in the car, automotive systems need to go digital. Most notably, this includes sensors. As semiconductor processes shrink to 90 nm and below, MCUs face a big challenge if they still must use 5-V I/O and 5-V analog-to-digital converters (ADCs) on-chip. For these submicron processes, the cost benefit of having analog components on a chip diminishes, and the challenge of maintaining a 5-V I/O becomes increasingly more difficult and expensive.

The answer to this challenge lies in the sensors. Smarter sensors could immediately convert the analog signals to their digital equivalent and send that information using a standard communication protocol at submicron-compliant voltage levels to the MCU. Alternatively, designers can overcome the need for certain analog sensors by designing them as "virtual sensors"—in other words, by calculating the estimated value of a real sensor using other available system information and the increased computing performance of the CPU cores.

Like any technological evolution, the move from an analog to a digital platform in the car will take time. Still, the process is well under way. As cost pressures continue and smaller submicron processes ultimately force the removal of analog components from the MCU, this future evolution will then propel the all-digital networked car from concept to production.

TAGS: Automotive
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