Tyre Pressure Monitoring Microsystems

Abstract

The need for monitoring the pressure and temperature of an automotive tire is increasing, and this paper will describe SensoNors products and philosophy that aim to meet these demands in the future.

SensoNor has designed a range of tyre pressure sensors to meet the different demands from the market. These designs are all based on SensoNors platform for pressure sensors, and include full temperature compensation and digital signal condition. The sensors are of a two-die design (sensor die and ASIC) overmolded by an epoxy resin. The patented buried conductor design with the triple stack glass-silicon-glass sensor element has proven an excellent media compatibility through extensive qualification tests run according to automotive requirements.

The design is optimised for high-volume production, and production volumes are currently ramping up to millions-per-year levels within 2001.

Currently these systems can be divided into two groups depending on the level of integration. One group of designs contains a state machine and logics for determining puncture- and high-temperature-conditions etc. These designs are to a large extend custom made, and closely linked to the system manufacturers system specifications. The other group is of a more general nature, with an SPI digital interface for use in systems with external microcontrollers.

These systems combined with pressure sensing elements for both passenger car and heavy vehicle pressure ranges and an accelerometer for detection wheel rolling, caters for large flexibility in the system design.