Melexis introduces a new generation of isolated integrated current sensors for vehicles

     Melexis announced the launch of the second generation of isolated integrated current sensor ics MLX 91220 (5 V) and MLX 91221 (3.3V). The two Hall Effect current sensor ics are suitable for a range of automotive and industrial applications, such as on-board chargers (OBCs), DC/DC converters, power supplies and small electrical drives. The product has A 300 kHz bandwidth and is suitable for a variety of power conversion applications below 50 A RMS.

     The MLX 91220/21 is based on a first-generation current sensor IC that integrates sensing elements and high-precision signal conditioning with voltage isolation. The new generation of current sensor ics is available in a miniature SOIC8 narrow-body package and SOIC16 wide-body package, with a bandwidth of up to 300 kHz and a response time of only 2 µs. Extremely short response times enable higher switching frequencies and more accurate control loop tracking.

     The MLX 91220 also improves two overcurrent detection (OCD) capabilities, enabling the necessary monitoring mechanisms through internal and external functions. The internal OCD threshold can be selected within or outside the detection current range with a response time of 2 µs; The external OCD threshold can be set at or near the output operating voltage range by external reference voltage, with a conventional response time of 10 µs. Both overcurrent detection functions can be used in the same application to provide redundancy or detect different cases of short circuits and out of current range.

     At factory calibration, Melexis has defined flexible output modes for the MLX 91220 and MLX 91221. Automotive applications typically prefer ratiometric analog output voltages, while industrial applications typically rely on fixed sensitivities based on reference voltages. The output mode is factory calibrated and can be selected by product ordering code.

     Unlike most current sensors, the MLX 91220/21 does not rely on a polymagnetic device, but instead uses an internal differential technology concept to detect the magnetic field generated by an internal primary current conductor. In addition, this differential concept provides a high level of stray field interference, which can support higher density power electronics, because the sensor is less affected by nearby stray magnetic fields.

     According to IEC/UL-62368, the SOIC8 package has a rated isolation level of 2.4 kVrms, while the SOIC16 widebody package has a rated isolation level of 4.8 kV. The SOIC16 package also offers lower primary conductor resistance because it has more pins and thicker conductors. Unlike the shunt resistance split solution, both versions of the chip have lower resistivity, with the SOIC16 version reaching 0.75 mOhm and the SOIC8 version reaching 0.85 mOhm, which is significantly lower than the shunt resistance-based solution.

     The MLX 91220 and MLX 91221 offer comprehensive functional integration and design flexibility, allowing customers to gain a competitive advantage by optimizing performance with just one product. To help customers simplify designs and benefit from new capabilities, Melexis is constantly developing new technologies to enhance its existing current sensor IC products.