Cost Efficient Side Airbag Chip Set with Improved Signal Integrity

In the case of a side impact the decision to deploy an airbag has to be taken much faster as it would be required for a front impact. Furthermore, there is a significant spread of the measurable acceleration depending on which pillars of the cars side are hit. Measuring the pressure inside the door as a direct result of an impact, the deformation of the door becomes observable. Based on pressure measurements side impacts can be detected much faster and more reliable. Therefore side airbag pressure sensors are established as add-on or replacement for side airbag acceleration sensors. This paper will present a Side Airbag Chip Set comprising of a side airbag pressure sensor and a satellite receiver. The system architecture and the partitioning between a single chip solution for the side airbag pressure sensor module plus the compatible satellite receiver will be described. A comparison to previous multi-chip solutions highlights the advances regarding reliability and effort in the system. Several techniques to improve signal integrity of current modulated data transmission between pressure sensor and satellite receiver will be discussed. This includes high level measures like CRC checks on the protocol and goes down to an analysis of EMC effect on the physical connection level. Hardware self test functions that monitor the availability of the system function will be introduced as well.