Date: 24/04/2009

Hall effect based current sensor device to measure currents of 50 to 200 Amps

Allegro Micro Systems has released a new hall effect based current sensor ACS758 to measure AC or DC currents. This device feature higher bandwidth and reduced output noise when compared to Allegro's earlier current sensor products. Typical applications include motor control, load detection and management, power supply and DC-to-DC converter control, inverter control, and over-current fault detection.

These device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the Hall sensor die. Applied current flowing through this copper conduction path generates a magnetic field which is sensed by the integrated Hall IC and converted into a proportional voltage. Device accuracy is optimized through the close proximity of the magnetic signal to the Hall transducer, and through the integration of a high performance ferromagnetic core into Allegro's custom CB package. A precise, proportional voltage is provided by the low-offset, chopper-stabilized BiCMOS Hall IC, which is programmed for accuracy at the factory.

The current sensor is immune to current conductor's dV/dt signals and stray electric fields. The terminals of the conductive path are electrically isolated from the sensor leads (pins 1 through 3). This allows the ACS758 family of sensors to be used in applications requiring electrical isolation without the use of opto-isolators.

The other features of lead-free sensor are, low output ripple and low offset drift in high-side, high voltage applications. The internal resistance of the current conductor is 100 micro ohms