Proven safety inserted into smart shunt solutions

Melexis releases the new MLX91231, increasing its automotive current sensor range by adding a shunt-based sensing solution. This IVT (current, voltage, and temperature) device meets functional safety requirements and combines high accuracy with the intelligence and flexibility of a digital MCU. The range is tailored for DC-DC converters, battery terminal sensors, low and high-voltage power distribution, and disconnection devices.

The accurate measurement of low-voltage electronics within vehicles has always been a critical factor for maintaining system performance and safety.

The intelligence in vehicles increases while a greater number of low-voltage ADAS functions are added. These functions rely on low voltage. This triggers a growing demand for high-performance, safe, and reliable current and voltage sensors.

The range produces excellent accuracy, featuring a lower than ±0.25% sensitivity drift error over temperature and lifetime and a 1.5μV input referred offset drift error over the same conditions. It permits closer monitoring and, therefore, greater optimisation of low-voltage systems, such as DC-DC converters, BTS, and power distribution and monitoring in zonal infrastructure. The range exhibits excellent output stability and EMC resilience, making it ideal for deployment in even the harshest automotive environments.

Using an integrated MCU, the range delivers advanced functionalities beyond current measurement. Supplied by a regulated 5V or directly by 12V battery, this IVT sensor supplies the current, voltage, and junction temperature readout via a selectable LIN or UART output. An important feature provided by the MCU is the presence of built-in diagnosable OCD. This enables the safe and simple triggering of pyro fuses without developing a complicated safety mechanism. The device is ASIL B(D) compliant per ISO 26262 and supports system-level integration up to ASIL D.

“The new MLX91231 shunt current sensor complements our Hall-effect-based portfolio. By offering multiple sensor technologies, we clearly articulate our commitment to all DC current and power sensing applications” says Bruno Boury, product line manager at Melexis. “With the safety systems baked into the product, we simplify engineers’ life with regards to safety compliance”.