Minimizing thermal losses is the special feature of the MLX91220 and MLX91221 current sensors from Melexis. They are suitable for AC and DC measurements with an analog interface. Both are isolated integrated Hall-effect current sensors for 0 to 50 A and dual overcurrent detection (OCD). This solution offers a symbiosis of small SMD footprint, low impedance, wide bandwidth and isolation.
Thanks to the dual overcurrent detection with separate output, the bill of materials is also reduced as no external protective measures are required. The sensors are suitable for use in automotive and industrial applications, DC/DC converters and small electrical drives, as well as power supply units. Their bandwidth of 300 kHz makes them suitable for use in power conversion up to 50 Aeff and the sensors offer low ohmic losses of the integrated conductor (0.9 mΩ for SOIC8 and 0.75 mΩ for SOIC16). Shielding against stray fields with regard to the differential measuring principle with two Hall sensors is not required. The combination of internal and external monitoring ensures optimization of the dual on-chip overcurrent detection. The response time of the internal OCD threshold is only 2 μs, that of the external 10 μs.
A special concept detects the magnetic field generated by the primary conductor. Therefore, no ferromagnetic concentrators are required. This enables power electronics with a higher density. The sensors operate in either ratiometric or differential/fixed mode. MLX91220 is designed for a supply voltage of 5 V, MLX91221 for 3.3 V. The isolation of the rated voltage is 2.4 k Vrms for SOIC-8 and 4.8 k Vrms for SOIC-16. Both current sensors are available immediately from Rutronik.
