First ASIL C safety-rated field current sensor for EV powertrain systems

Allegro MicroSystems has released samples for the ACS37601, an ASIL C safety-rated, high-precision, field current sensor offering best-in-class accuracy for traction and auxiliary inverter systems and BMS in EVs.

Designers of inverters and BMS are challenged to deliver higher safety targets based on new ASIL requirements.

To allow customers to satisfy these new safety demands while increasing system efficiency and extending battery life, the company has designed the ACS37601 programmable linear Hall-effect current sensor IC with overcurrent, overtemperature, and self-test capabilities. Created to attain high accuracy and resolution without compromising bandwidth, the device is its highest-accuracy field current sensor for applications needing measurement capability greater than 200A.

“Allegro’s ACS37601 is enabling us to meet e-mobility functional safety and accuracy requirements in our BMS and EV traction inverter current sensor applications,” says Julio Urrea, vice president of Business Development at Littelfuse.

To be employed along with a C-core, the device is the first ASIL C-rated field current sensor that reaches 0.8% sensitivity error and less than 5mV offset error over the automotive temperature range, and, with 30% less noise than legacy devices, this IC is excellent for battery management applications. The high operating bandwidth from DC to 240kHz and fast 2μs response time allow new performance in DC battery charging and high-frequency automotive inverter applications. To support the adoption of the most advanced microprocessors without needing further components, it works with 5V or 3.3V power supplies.

“Littelfuse has a history of excellence as an automotive supplier with a tremendous global footprint. We are excited to work with them to deliver industry-leading magnetic current sensor accuracy and safety to EV powertrain applications,” says Shaun Milano, business unit director for current sensors at Allegro.

To assist designers in delivering the most-advanced ASIL-compliant battery management and inverter systems, samples of the device are offered in an extremely thin (1mm-thick), 4-pin SIP, referred to as the KT package. The KT package is offered in straight leads (suffix TN) and a lead-formed option (suffix TH), facilitating surface-mount assembly and a high tolerance to mechanical vibrations. The package is lead (Pb) free, with 100% matt tin leadframe plating.