The ACS37030 product family by Allegro Microsystems targets applications with high demands on the frequency range; the semiconductor promises a bandwidth ranging from DC to a total of 5 MHz.

Inside the housing, two signal paths can be found. Firstly, a Hall Effect element is used to capture direct current and or low current information, while an inductive coil is used for the high frequency parts.

The secret of the system, shown in the flowchart in the figure, is in the signal processing. 

Technology developed by Allegro Microsystems unifies current consumption information collected by the two elements, which is then output as an analog voltage.Designers wanting to collect this information simply connect to an ADC of their choice in order to receive an accurate reading of the current flowing between the terminals IP+ and IP-.

Advanced Specifications Simplify Integration

Current measurements are one of the easiest ways to break galvanic insulation. In the case of the ACS37030, Allegro paid close attention in ensuring that the surface-mount housing respects insulation distance. The pinout shown in the figure has ample spacing between the hot (current-bearing) and the cold (signal-bearing) parts of the integrated circuit.

In addition, the semiconductor's internal design also ensures comprehensive galvanic insulation. In particular, the datasheet claims the following quite impressive insulation values:

The IC has no physical connection to the integrated current conductor and provides a 3500 V RMS isolation voltage between the primary and secondary signal leads of the package. This high rating provides a basic working voltage of 840V RMS.

Another interesting question concerns the measuring range: Allegro offers three different chip variants, which support current-sensing ranges from +/—20 to +/—60 amperes. As for the accuracy, the data sheet provides the values shown in the figure.

Another significant question concerns the resistance of the part integrated into the current flow. Due to the efficient internal architecture, Allegro Microsystems can reach a contact resistance of only 0.6 mΩ —this is minimal and ensures that almost no energy dissipates. Finally, the frequency stability also deserves praise. The sheet provides both phase and magnitude plots, which are shown in the figure below.

Conclusion

The Allegro Microsystems ACS37030 is an effective way to determine information about current consumption. Thanks to the ingenious two-element construction, the part runs smoothly when dealing with wide bandwidth signals.