Melexis Enhances Current-Voltage Sensors with New Thermistor Input

Melexis has introduced a significant enhancement to its current-voltage sensors, the MLX91230 and MLX91231, by integrating a negative temperature coefficient (NTC) thermistor input. This new feature improves the sensors’ ability to detect temperature variations within systems, making them particularly suitable for safety-critical automotive applications. The integration allows for better compensation of residual variability in shunt resistors due to temperature changes.

The MLX91231, designed specifically for shunt interfaces, benefits greatly from this addition. According to the company, the NTC input not only enhances performance but is also compliant with ASIL C standards. This compliance is essential for deployment in areas such as automotive batteries, direct current (DC) fast charging systems, smart pyro-fuses, and power distribution modules.

Enhanced Measurement Capabilities

Both the MLX91230 and MLX91231 sensors feature three measurement modes for their voltage input pin. The NTC thermistor input can interface with external values ranging from 500Ω to 500kΩ, with the 10kΩ Murata NCU18XH103F6SRB recommended in the product data sheet. The integration of this thermistor input aligns with ASIL C functional safety compliance to ISO 26262, which encompasses current, voltage, and external NTC measurements, along with diagnosable over-current detection. This over-current detection capability enables direct input to a pyro-fuse driver, enhancing safety measures in automotive systems.

Additionally, the sensors provide internal die temperature readings, which are also available in other variants of the MLX91230 and MLX91231 that do not include NTC inputs. The internal microcontroller within these sensors can relay data in LIN or UART format through dedicated pins, and can also manage hardware over-current warning outputs. Furthermore, developers can create custom software tailored for the internal microcontroller, offering flexibility and adaptability for various applications.

Access and Further Information

For those interested in exploring these new features, Melexis has made product details accessible through their official website. Links to the respective product pages for the MLX91230 (Hall sensor) and MLX91231 (shunt sensor) are available, providing comprehensive technical specifications and additional resources for engineers and designers.

This development underscores Melexis’s commitment to advancing technology in the automotive sector, particularly in enhancing the safety and efficiency of electrical systems. As the demand for robust and reliable automotive components continues to grow, innovations such as these are vital in meeting the evolving needs of the industry.