Current sensors deliver high accuracy measurements

Today’s current sensor modules are often bulky, intrusive and inefficient, and are prone to potential system failures. This results in major design complexities that often mean increased cost and longer production time. In response to the challenges, Allegro MicroSystems, Inc. has launched two high bandwidth current sensors, based on its XtremeSense tunnel magnetoresistance (TMR) technology. These XtremeSense current sensors are designed to streamline high-power-density designs, improve energy efficiency and provide space and cost improvements.

The CT455 and CT456 current sensors feature high-bandwidth and low noise to deliver precise current measurements for AI data center and automotive powertrain applications.

Allegro MicroSystems said these TMR sensors enable smaller, more efficient and high-accuracy current measurements on PCB or busbar applications from 80 A up to above 800 A, depending on the configuration. The best performance advantages are in the 80-200 A range.

(Source: Allegro MicroSystems)

These latest Allegro TMR sensors, the first introduced since its acquisition of Crocus Technologies, provide a contactless solution, delivering 1-MHz bandwidth and a 300-ns response time to enable faster power conversion. Features include a preset magnetic field range of ±6 mT supporting high current measurements and low-noise performance to improve measurement sensitivity. They are optimized for rapid changes in voltage over time (high dv/dt) and are offered in 8-pin SOIC and TSSOP package options.

The CT455 enables high-accuracy current measurements for consumer, enterprise and industrial applications, supporting two standard field ranges where it senses and translates the magnetic field into a linear analog output voltage. It features less than 300-ns output response time while the current consumption is approximately 6.0 mA.

The CT455 is also available in a user-programmable variant, which enables end-of-the-line calibration of gain and offset. Pre-programmed to compensate for gain and offset temperature drift, the sensor’s capability to adjust offset and gain “relaxes” mechanical tolerances during sensor mounting.

The CT456 is a high-bandwidth and low-noise integrated zero-loss contactless current sensor using XtremeSense TMR for high-accuracy current measurements. The device supports a preprogrammed 6-mT field range where the CT456 senses and translates the magnetic field into a linear analog output voltage. It features a small footprint and is easily incorporated into a design, while providing effective common-mode rejection.

The CT456 has greater than 90% immunity to stray magnetic fields, with almost no impact on the accuracy of the current measurement, due to its differential measurement, according to the company.

The CT455 is housed in an 8-lead SOIC package with a very low profile or an 8-lead TSSOP package. The CT456 is assembled in a low-profile, 8-lead TSSOP. Both devices are “green” and RoHS compliant. Evaluation boards for the CT455 and CT456 are available.