Crash sensors complete airbag electronics kit

The sensors are designed to be mounted in the vehicle’s Airbag Control Unit (ACU), responsible for evaluating the sensor data and triggering the appropriate restraint system.

Each sensor includes two independent sensing channels for redundancy and incorporates both slow and fast offset cancellation as well as precise temperature compensation for optimum stability. Built-in power-on self-test ensures reliability and run-time diagnostics help developers achieve the required level of functional safety. Both sensors have standard 400Hz signal bandwidth, which the user can extend to 1600Hz.

With around 1,000 MEMS-related patents and patent applications worldwide, ST has leveraged its leadership in this technology to integrate the precision mechanical sensing element in the same package with a 3.3V-compatible interface IC featuring a 14-bit digital SPI output.

The AIS1120SX and AIS2120SX sensors are specified over the extended temperature range from -40 to +105°C. They will enter full production in Q1 2016 in a plastic full-molded SOIC8 package.

Airbag system producers can now satisfy the complete system functional requirements by teaming the AIS1120SX or AIS2120SX central crash sensors with peripheral accelerometers like ST’s AIS1200PS installed on structures such as bumpers and door pillars. The sensors interact with an airbag system IC and a safety MCU, which coordinate airbag activation.

A choice of three airbag system ICs, the L9678, L9679, and L9680 meet the demands of applications ranging from entry or mid-level to high-end vehicles with multiple airbag firing loops. These devices, which integrate system power management, sensor interfaces, switch interfaces, and arming safety logic, are responsible for decoding the sensor data and forwarding results to the MCU.

Based on the 32-bit Power Architecture, ST’s SPC5 automotive MCU family includes Safety Line devices that offer a choice of single- or dual-core configurations with up to 1MB of Flash. Multiple DSPI (Deserial Serial Peripheral Interface) channels optimise system and diagnostic control. In addition to that, a Fault Collection and Control Unit (FCCU) and built-in self-tests provide safety coverage for ASIL (Automotive Safety Integrity Level) development.