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Contact less high DC/AC current sensor for Electric Cars

Date: 29/01/2013
Melexis has introduced its new MLX91209 high-speed custom programmable Hall-effect sensor for contact-less current sensing in renewable energy, Hybrid Electric Vehicle (HEV) and Electric Vehicle (EV) applications. The MLX91209 is a fully customer programmable monolithic sensor IC packaged in a standard SIP package. MLX91209 produces analog output signal proportional to the external applied flux density so that it can be used to design precision programmable current sensors.

The MLX91209 can be used to measure both DC and/or AC currents up to 200kHz with galvanic isolation.

Typical applications are particularly found in battery current monitoring in solar power converters and automotive inverters driving the traction motor in HEVs and Evs where the serial current shunt in DC current measurement is cumbersome.

The high-speed Hall effect sensor is automotive-qualified and senses current by converting the magnetic field generated by currents flowing through a conductor to a voltage, which is proportional to the field.

The transfer characteristic of the MLX91209 is fully customer programmable. Parameters such as sensitivity and offset are stored in an internal EEPROM memory. Calibration is done using Melexis’ PTC (Programming Through Connector) protocol. This method modulates the supply voltage and does not require any additional pin for programming. A linear analog output permits use of the sensor in applications where a very fast response of 3µs is required.

Custom calibration is best performed in-situ after the sensor is fixed with respect to the current conductor and ferromagnetic core so that a calibrated current sensitivity is achieved. Typical accuracy of a current sensing system based on the MLX91209 is better than ±0.5% at room temperature or ±2% over the full temperature range (from -40 to 125°C) when applying in-circuit end of line calibration.

The MLX91209CA features a programmable sensitivity range from 5 to 150mV/mT. The sensor is packaged in a 4-pin SIP, RoHS compliant lead-free package. Engineering samples are available now upon request.