The MLX91220/21 is based on the first generation of current sensors, which integrated high-precision sensing and signal conditioning elements with voltage isolation. The new generation of current sensors, available in narrow-body SOIC8 miniature packages and wide-body SOIC16 packages, improves upon this by increasing the bandwidth to 300 kHz, resulting in a response time of only 2 µs. This response time supports higher switching frequencies and more precise tracking in control loops.
The MLX91220 also enhances the dual on-chip overcurrent detection (OCD) function, enabling essential monitoring mechanisms using both an internal and an external feature. The internal OCD threshold can be selected as either within or outside the operating range, with a response time of 2 µs. The external OCD threshold can be set, via an external reference voltage, to within or near the output operating range, with a typical response time of 10 µs.
Both can be used in a single application to provide redundancy or to detect separate short-circuit and out-of-range conditions.
The MLX91220 and MLX91221 offer factory-defined output mode flexibility from Melexis. Automotive applications typically prefer ratiometric analog output voltages, while industrial applications often rely on fixed sensitivity built around a reference voltage. The output mode is factory-set and selectable using intuitive product order codes.
Unlike most current sensors, the MLX91220/21 does not rely on ferromagnetic concentrators. Instead, it uses an internal differential sensing concept to detect the magnetic field generated by the integrated primary conductor. This differential concept also provides a high level of immunity to stray fields, allowing for higher-density power electronics, as the sensor is less affected by nearby stray magnetic fields.
The SOIC8 package has an insulation capacity of 2.4 kVrms according to IEC/UL-62368, and the wide-body SOIC16 package doubles this insulation capacity to 4.8 kV. The SOIC16 package also offers lower primary conductor resistance, thanks to its greater number of pins and increased conductor thickness. Both variants are distinguished from discrete shunt solutions by their lower resistivity: the SOIC16 measures 0.75 mΩ, while the SOIC8 measures 0.85 mΩ, significantly lower than shunt-based solutions.
The extensive feature integration and design flexibility offered by the MLX91220 and MLX91221 models provide customers with a competitive advantage when seeking to optimize performance using a single product. To help customers simplify design and benefit from new features, Melexis is continuously developing new technologies to enhance its existing sensor offering. Samples and a development kit are now available.
