Top 5 automotive hall efffect sensors for modern ADAS and EV cars
Date: 07/07/2022
Irrespective of driving automation, and other advanced operational automation in automotives, there are lot of sensors required to ensure normal operation, safety, reliability, and maintenance of automotives. Along with various other sensors used in cars, Hall effect sensors are gaining importance for monitoring the health of the vehicle , as well as for safety and driving automation.
Since Hall effect sensors operate contactless, they are reliable, and can withstand harsh automotive weather conditions. However due to the complexity of manufacturing, these sensors are yet to be commoditised and cost optimized. In this article we try to list top five hall effect sensors in automotives for various applications:
1. Graphene Hall effect sensor by a new company called paragraf:
A thin coat of Graphene over hall effect sensor does magic in terms of sensitivity and avoiding stray magnetic fields.
Though detailed specification are not available for this company's part named PG220505_GHS-series. However the brochure lists out various advantages of this product over non-Graphene Hall effect Sensor. This cost saving devices operates accurately under Ultra strong magnetic field, withstand high levels of gamma neutron radiation, and very high temperature and also at cryogenic temperature. Due to precise magnetic field measurement, can offer highest sensitivity for current measurement. Highly suggested for measuring current density distribution within battery cells of electric vehicles. Graphene Hall effect sensors are set to be ideal for magnetic field and current measurement in emerging industrial battery consumer and electric machine applications. Other features include low noise ultralow power consumption no hysteresis and no saturation in output.
Since the datasheet is available only on request, for further information on this product visit:
https://www.paragraf.com/graphene-hall-effect-sensors/
2. MLX90395, a 3D magnetic field sensor from Melexis:
MLX90395, an automotive-grade (AEC-Q100) monolithic Hall effect sensor made by Melexis uses the Hall effect to provide 16-bit digital output of analog measurement of X, Y and Z magnetic field. The user of this device is given the option to select any of the fields through wired control for position sensing. The receiving of magnetic vectors is through serial interfaces such as SPI and I2C. By using a microcontroller or any processor absolute position of any permanent magnet can be made by analysing the magnetic field data. MLX90395 can measure magnetic fields of a static or moving magnet placed closed to it. The special feature of this device includes measurement range is programmable and provides option to extended magnetic sensing range and selectable digital output with programmable duty cycle: 16-bit magnetic field (XYZ), 16-bit supply voltage (V), and 14-bit temperature (T).
The MLX90395 is available in two magnetic field versions of 50 Mt and high-field of 120 Mt. The high field portion is for those applications where there is a presence of stray magnetic field produced by another magnet or a current carrying conductor. MLX90395 is made available in packages of SOIC-8, TSSOP-16 (dual-die for redundancy) and QFN-16 (with wettable flanks). RoHS compliant AEC-Q100 qualified MLX90395 can withstand a temperature range of -40 °C to +125 °C, making this device eligible for both automotive or industrial control environment.
MLX90395 consumes idle current of 1.4 mA and standby current of 2.4 mA, and supply current of 4 milli Amperes or less. MLX90395 also integrates a temperature sensor and supply voltage monitor. Three state machines and operates in one of three modes: single measurement, burst mode and wake-up on change mode.
Bus protocol (SPI or I2C) is also selectable, running at up to 10 MHz for SPI and 1 MHz for I2C. Each sensor comes with a unique 48-bit ID number some exclusive free space to store customer traceability information.
For more details on this product please visit:
https://www.melexis.com/en/product/MLX90395/Triaxis-3D-micropower-magnetometer
datasheet can be downloaded from the link:
https://media.melexis.com/-/media/files/documents/datasheets/mlx90395-datasheet-melexis.pdf
If you're new to this type of measurements/sensors, there is a nice solution article to guide you on how to use this device at:
https://www.melexis.com/en/tech-talks/triaxis-position-sensing-solution
3. ACS37610 from Allegro
ACS37610 is a coreless Hall effect sensor from Allegro Microsystems designed for industrial and automotive systems. This hall effect sensor is used to measure the current flowing through busbars, and PCB trace with 1% accuracy. The sensor accurately measures current in the range of 100 A to >4000 A in electric vehicles motor traction system. This sensor does not need a concentrator core and uses differential measurement to make it immune from stray magnetic fields. This sensor delivers higher signal-to-noise ratio and operates in the temperature range of -40°C to 150°C. Due to this precision it helps in accurately controlling the torque of the motor.
The automotive applications suggested include high-voltage traction motor inverter, battery monitoring, overcurrent detection, smart fuse and any such high current monitoring applications. The industrial applications include DC DC converters DC/AC inverters and power distribution in grid infrastructure.
This device is made available in the packages of low-profile 8-pin surface mount TSSOP package (thin-shrink small outline package, suffix LU).
To know more about this product please visit:
https://www.allegromicro.com/en/products/sense/current-sensor-ics/sip-package-zero-to-thousand-amp-sensor-ics/acs37610/
The datasheet can be downloaded at https://www.allegromicro.com/-/media/files/datasheets/acs37610-datasheet.pdf
4. HAL 15xy from TDK.
HAL 15xy family from TDK are hall effect sensors used to sense brake fluid level, detect seat belt, and activate brake light switch . These devices operate the temperature range of -40°C to 170 C. They come with unique power on self test where a full functional test of sensor signal processing path and output can be done before making them use for normal operation. There is highly reliable sensors operate from voltages of 2.7 V to 24 V. They fulfil high ESD levels up to ±8 Kv (HBM).
These are available in the packages of small SOT23 SMD package and TO92-UA package with various lead forms.
To know more on HAL 15xy visit:
https://www.micronas.tdk.com/en/products/hall-switches/hal-15xy
5. ATS16951 (crankshaft) and ATS16351 (camshaft) sensors from Allegro
These two new sensors from Allegro is designed for hybrid electric vehicle engine. ATS16951 is a crankshaft sensor where it incorporates multiple joint magnetoresistance elements into a single IC and permanent magnet pellet combined with integrated electromagnetic C protection components. This sensor senses digital gear tooth. This IC also integrates the compensation circuit to eliminate detrimental effects of magnet and system offsets. The other features of this IC includes Digital speed and direction output provides ferromagnetic target position information, Enhanced algorithm for low jitter, high output accuracy
performance, and vibration tolerance, Center of package switching alignment option, Programmable pulse location between center of target feature or edge of target feature, EEPROM programmable performance optimizations and production traceability and Target Profile Diagnostics. ATS16951 meets ISO 26262 and ASIL B. This sensor is available in 3 pin SIP leadfree package.
More information on this product is at:
https://www.allegromicro.com/en/products/sense/magnetic-speed/crankshaft-sensor-ics/ats16951
The datasheet this product is available at:
https://www.allegromicro.com/-/media/files/datasheets/ats16951psm-datasheet.pdf
ATS16351 is a camshaft sensor where it incorporates multiple joint magnetoresistance bridge and a customized magnetic circuit that responses to magnetic signals from a ferromagnetic target. This chip also integrates digital circuit design to match the temperature behaviour of the sensor IC with integrated magnet. The auto true power on State feature of this IC alllows the sensor IC to learn the installation air gap inside the engine and to intelligently reprogram into memory the optimal threshold for power on accuracy. The other key functions include EEPROM programming, flexible orientation, stray field immunity, backward compatibility, and target profile diagnostics.
More information on this product is at:
https://www.allegromicro.com/en/products/sense/magnetic-speed/camshaft-sensor-ics/ats16351
The datasheet of this product is available at:
https://www.allegromicro.com/-/media/files/datasheets/ats16351psm-datasheet.pdf
To give you some more examples of older market-matured hall effect sensors:
6. TLE4999I3 sensor IC two Hall sensors for angular and linear position sensing into one device for strictly-regulated automotive applications.
7. HAR 3927 from TDK meets ISO 26262 compliance for position sensing and features full redundancy with two dies in one.
8. Hall-effect sensor IC MLX91377 packs Hall-effect sensor, ADC, and a signal processor for applications such as steering torque sensing and other such automotive or industrial applications.
9. CUR4000 from TDK senses high currents of both AC and DC, it can be used in high-voltage battery monitoring system of hybrid electric vehicles.
10. Allegro' A31315 rotary and linear magnetic position sensing in automotive. A31315 measures along three axis to determine absolute linear and rotary position up to 360°. This chip can be used in steering, braking, transmission, and throttle system.
