Next-generation Hall-effect current sensor from Allegro combines high speed and low noise for 50-100 A current measurements

The device consists of a precision, low-offset linear Hall sensor circuit with a copper conduction path located near the 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 optimised through the close proximity of the magnetic signal to the Hall transducer. A precise, proportional voltage is provided by the low-offset, chopper-stabilised BiCMOS Hall IC, which is programmed for accuracy at the factory.



The new device offers faster response times than earlier products, with a 3 microsecond rise time in response to a step input current and a propagation delay of only 1.6 microsecond. Output sensitivity is 20 or 40 mV/A, and noise levels of less than 9 mV peak-to-peak.



The ACS756 offers higher accuracy and lower drift over temperature than earlier devices, with a total output error of only 0.8% at a temperature of 25°C. The 130 microhm internal conductor resistance leads to ultra-low power losses, while an internal electrostatic shield effectively shunts the effects of voltage transient spikes around the sensor IC and minimises the voltage ripple on the output of the device.



The result is a high performance current sensing solution suitable for motor and invertor control, power-supply control and protection, and other applications requiring high-side current sensing.