Current sensor ICs from Allegro MicroSystems Europe senses up to 400A

Current sensor ICs from Allegro MicroSystems Europe are designed for AC or DC current sensing. The ACS772 and ACS733 have a 200kHz bandwidth for motor control, load detection and management, power supply and DC/DC converter control, as well as inverter control. The 2.5-microseconds response time enables over-current fault detection in safety-critical applications.

The ACS772 and ACS733 ICs can be used in automotive and industrial applications with an accuracy of ±2.1 per cent over the lifetime of the IC. Both current sensor ICs work from a single supply 5.0V (ACS772) and 3.3V (ACS773).

The current sensor IC consists of a precision, low-offset linear Hall circuit with a copper conduction path located near the die. Applied current flowing through this copper conduction path generates a magnetic field which the Hall IC converts into a proportional voltage. According to Allegro Microsystems, accuracy is optimised through the close proximity of the magnetic signal to the Hall transducer. A proportional output voltage is provided by the low-offset, chopper-stabilised BiCMOS Hall IC, which is factory-programmed for accuracy. Proprietary digital temperature compensation technology improves the IC accuracy and temperature stability, adds Allegro.

High-level immunity to current conductor dV/dt and stray electric fields is offered by Allegro’s proprietary integrated shield technology for low output voltage ripple and low offset drift in high-side, high-voltage applications. The output of the device increases when an increasing current flows through the primary copper conduction path (from terminal four to terminal five), which is the path used for current sampling. The internal resistance of this conductive path is 100-mcroOhm typical, providing low power loss. The thickness of the copper conductor allows survival of the device at high overcurrent conditions.

The terminals of the conductive path are electrically isolated from the signal leads (pins one to three). This allows the ACS772 family of sensor ICs to be used in applications requiring electrical isolation without the use of opto-isolators or other costly isolation techniques.

The ACS722 and ACS733 current sensor ICs are provided in an Allegro custom CB package that provides a very small form footprint over current sensor modules offered by competing solutions. These devices also offer a 2.5-microseconds response time, which is the fastest response time of an IC ever offered in the custom Allegro CB package. It is fully calibrated prior to shipment from the factory and is lead (Pb) free. All leads are plated with 100 per cent matt-tin, and there is no Pb inside the package. The heavy gauge leadframe is made of oxygen-free copper. 

http://www.allegromicro.com

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