The Allegro™ ACS724 current sensor IC is an economical and

precise solution for AC or DC current sensing in industrial,

automotive, commercial, and communications systems. The

small package is ideal for space-constrained applications

while also saving costs due to reduced board area. Typical

applications include motor control, load detection and

management, switched-mode power supplies, and overcurrent

fault protection.

The device consists of a precise, low-offset, linear Hall

sensor circuit with a copper conduction path located near the

surface of 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. The current is sensed differentially in order to reject

common-mode fields, improving accuracy in magnetically

noisy environments. The inherent device accuracy is optimized

through the close proximity of the magnetic field to the Hall

transducer. A precise, proportional voltage is provided by the

low-offset, chopper-stabilized BiCMOS Hall IC, which is

programmed for accuracy after packaging. The output of the

device has a positive slope when an increasing current flows

through the primary copper conduction path (from pins 1 and

2, to pins 3 and 4), which is the path used for current sensing.

The internal resistance of this conductive path is 1.2 mΩ typical,

providing low power loss.

The terminals of the conductive path are electrically isolated

from the sensor leads (pins 5 through 8). This allows the

ACS724 current sensor IC to be used in high-side current sense

applications without the use of high-side differential amplifiers

or other costly isolation techniques.