Roundup: Automotive Hall Effect Sensors Find New LifeMay 24, 2021 by Jake Hertz
With the recent focus on EVs, new Hall Effect sensors have been hitting the market, some are even using new technologies.
Hall Effect Sensors (HES) is a classic electronic component that has been around for decades. Yet, unlike many older technologies, HES never found itself obsolete, with the same, yet improved, versions still being widely used today.
A graphic showing how a general HES works. Image used courtesy of The Engineering Project
One field that has found itself continually in need of HES is the automotive industry, specifically with the rise of advanced driver-assistance systems (ADAS).
Advancements in these systems have presented new performance and operational safety challenges for system integrators. The cars need to reliably detect steering wheel position, braking, throttle, transmission, etc.
For these reasons, in the past couple of months alone, a series of new HES have been released by multiple different companies, all of which have the automotive industry in mind.
This article will explore the latest sensors and see how they hope to be applied to the automotive industry.
TDK’s New Offerings
Firstly, TDK is powering up the HES market by releasing two new HES in the past month alone, both of which are automotive facing.
The first TDK sensor is its CUR4000, a new automotive safety integrity level B (ASIL-B) compliant HES, specifically for EV battery monitoring. The product is designed for DC, and AC measurements, explicitly aimed at high-power EV batteries with a dynamic current range of 2000 A. The CUR4000 offers a hysteresis-free output, a non-linearity error of ±0.2%, an output-offset temperature-drift below ±0.05% at full scale, and a noise performance of ±0.005% with a signal bandwidth of 8 kHz.
CUR4000 HES from TDK. Image used courtesy of TDK
Following this product, TDK announced the newest version of its HAL 37xy sensor family, which has now been updated to be ASIL-B compliant. These HES uniquely integrate vertical Hall plates into the process via TDK's 3D HAL technology.
The result was the ability for the IC to evaluate relative horizontal and vertical magnetic field components, as compared to conventional planar Hall technology is only sensitive to the magnetic field orthogonal to the chip surface. By offering an accuracy of ±1.5° at 30 mT, these new sensors could benefit angular rotation detection and linear position detection, which is essential for steering systems and throttle control.
Adding to the trend of HES, Allegro also released its sensor that is fairly similar to the HAL 37xy family.
Allegro’s 3DMAG HES
The A31315 is an ASIL-D compliant HES meant to enable rotary and linear magnetic position sensing in automotive applications. Similar to TDK, this is achieved by combining planar and vertical Hall plates to allow the measurement along three axes, which allows this sensor to determine absolute linear and rotary position up to 360 degrees.
A31315 HES from Allegro. Image used courtesy of Allegro
The IC offers a native active angle error over the temperature in any plane of ±1.2° from -40°C to 150°C, linearity error of ±0.3%, and channel sensitivity error drift of ±2%. Allegro sees this chip being useful in ADAS applications, including steering, braking, transmission, and throttle systems.
Paragraf’s Graphene HES
AAC had the chance to interview Dr. Ellie Galanis from Paragraf when it released the world’s first graphene HES back in March. This HES has completely changed the game in many fields, including cryogenic applications, but one of the original applications for this new device was actually the automotive industry.
GHS01AT graphene Hall sensor. Image used courtesy of Paragraf
Its new HES, the GHS01AT, performs very close to expensive magnetic field sensors, yet in a much smaller, cheaper, and lower-power device. The sensor achieves a resolution <0.2 ppm, consumes power on the magnitude of picowatts, and withstands up to 250°C. When used for battery testing and monitoring, its graphene HES is uniquely able to measure the currents blowing in battery cells (in the μT to the mT range).
For these reasons, Paragraf sees immense promise for its HES in the automotive industry.
A Safer Future
With the rise of ADAS, the automotive industry has found itself in need of electronic components that comply with stricter safety standards, offer higher performance, and come at lower power consumption. One of the components most sought after in this light is the HES, and companies across the industry are working to push out products that meet automotive needs.
Between the new announcements from TDK, Allegro, and Paragraf, it's clear that there's no shortage of work going on in the field, and more innovations in HES are sure to come.
Interested in other advances in HES technology? Find out more by reading the articles down below.