The MLX91804 incorporates a sophisticated microcontroller and MEMS-based pressure sensing element, as well as energy efficient 315/433MHz wireless transmitter that supports data rates up to 150kbits/s, and a 125kHz receiver for communication with the vehicle’s relevant electronic control unit (ECU). A 16kByte embedded program memory is included for the storing of custom application data/libraries. In addition, there is a built-in single or dual axis high-g range accelerometer to support all available wheel sensor auto-location functionalities.
The combination of minimal footprint and high degrees of integration offered by the MLX91804 means that a significant reduction in PCB size can be realised. Likewise, the device’s low power consumption permits a downsizing of the specified battery. All this results in a smaller size and lower weight sensor module.
Together with high-g range and fast data acquisition accelerometer, it also represents a step closer to the tyre mounted sensor implementations that automotive Tier 1 suppliers are looking to use in the future. The MLX91804 is said to be resilient to shock and operates across a temperature range of -40 to 125°C allowing it to deal with a harsh in-tyre environment.
“Monitoring tire pressure is now an essential part of modern vehicle design,” states Ivan Zagan, product manager for TPMS at Melexis. “Global uptake of TPMS is increasing all the time, driven by international regulations and increasing emphasis on the safety of road users. This device will enable more compact solutions with greater functionality and improved energy efficiency, in line with vehicle manufacturers’ growing expectations."
