Melexis Unveils Current Sensors for Automotive Power Conversion and BMS Applications

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Melexis has released new current sensors for automotive power-conversion applications. The advantages they deliver include increased resolution, optional 3.3 V or 5 V operation, and integrated over-current detection circuitry.

The MLX91219 is a conventional hall current sensor. Using a ferromagnetic C-core, currents can be measured in the ranges of 200 A to beyond 2000 A. The MLX91218 is an IMC-Hall current sensor. With a flexible U-shield for crosstalk immunity, currents can be measured in the ranges of 200 to 2000 A. Both sensors benefit from an increased signal-to-noise ratio (SNR), nearly 2 times greater than preceding generations.

Featuring high linearity, within ±0.3 % full scale, the AEC-Q100 automotive-qualified sensors deliver enhanced accuracy for managing high-speed applications such as motor control, inverters, and converters, but also redundant monitoring of battery management systems (BMS). Minimal thermal drift, maintaining electrical offset within ±5 mV and sensitivity within ±1 %, ensures accuracy over a wide temperature range. With the option of either 3.3 V or 5 V operating voltage, designers can use these sensors directly in circuits containing new 3.3 V low-voltage microcontrollers or with legacy 5 V devices.

The MLX91218 and MLX91219 integrate over-current detection (OCD) circuitry typically implemented off-chip using an external window comparator, thereby further simplifying system design, saving board space, and reducing the bill of materials. The over-current threshold is set internally during the initial product configuration. The SOIC8 packaged products have an additional pin that allows setting the threshold voltage with increased accuracy using an external voltage divider. Two indicator pins show the overcurrent status in relation to internal and external thresholds, with 2 us and 10 us response times respectively.

Both sensor types provide a selectable analog output that allows the choice of a fixed output or ratiometric output that scales with the supply voltage. With 400 kHz bandwidth and fast response time, they are suitable for circuits designed to operate at high switching speeds and fundamental frequencies to minimize phase delay in the control loop. In addition, the future MLX91218 incorporates Melexis’ patented IMC integrated magnetic concentrator to optimize magnetic field shaping, which allows compact, lightweight shielding.

The MLX91219 is available in a single inline (SIP) 4-pin package. The MLX91218 and the small-outline SOIC8 package for MLX91219 will be available soon.