Triaxis®: Position Sensing Solution
What are Triaxis® Sensors?
Traditional Hall sensors are only sensitive to the magnetic flux density perpendicular to the surface of the Hall element and consequently IC and package. These single-axis devices enable many applications like accelerator pedal position detection, joystick position detection, and proximity sensing, among others. Due to their 1D nature, and the fact that the output is proportional to the magnetic flux density, it is sometimes necessary to design complicated magnetic structures to achieve the desired measurement range and accuracy, especially over a wide temperature range taking into account a thermal drift of the biasing magnet.
Triaxis® sensors, on the other hand, are an innovative magnetic sensor technology that enables measurement of the three magnetic flux vectorial components in a single integrated circuit. This is done by combining standard planar Hall effect technology with a unique Integrated Magnetic Concentrator (IMC®). Using the three magnetic components, it is possible to create 2D or 3D sensors that enable rotary (angle), linear (stroke), or even joystick type applications or 3D-magnetometers that output the individual magnetic components.
Strengths of Triaxis®Triaxis® sensors are small, capable of high temperature operation and can support a wide variety of sensing applications by adjusting the on-chip magnetic angle computation. A single IC can support anywhere from one to three types of applications just by reprogramming the device. Since the angular computation is a relative measurement between two magnetic flux components the measurement is robust to temperature variations but also magnetic and mechanical (e.g. airgap, eccentricity) tolerances. Additionally, if an additional calibration process is performed after assembly, excellent linearity and accuracy can be obtained as mechanical tolerances are compensated for and a variety of simple, low cost magnets can also be used.
As the magnetic field is being sensed the sensors are intrinsically insensitive to dirt, dust, oil, gas and other contaminants. The IC itself can be overmolded in plastic or potted to protect the IC itself from these contaminants and ensure long life even when exposed to harsh media.
A variety of IC packages are available from the industry standard SOIC8, TSSOP16, and QFN16 to the Melexis Dual-Mold Package (DMP). The SOIC8, QFN16, and DMP all contain a single sensor die. The TSSOP16 contains two sensor dies that are fully redundant with independent supply, ground, and output enabling redundant operation. The DMP is intended to be integrated without a PCB via a direct connection to the connector leadframe. This can bring packaging, cost, and reliability advantages.
Finally, Triaxis® sensors contain a suite of onboard diagnostics to ensure safe and correct operation. Melexis can provide additional supporting documentation to conduct the necessary safety analysis to ensure ASIL / ISO26262 requirements are met.
Where are Triaxis® Sensors Used?
Automotive Position SensingSteering angle, pedal position, electronic throttle body, EGR valve, shifter, turbo actuator, motor position, chassis height, and more.
Beyond Automotive ...Agricultural vehicles and equipment, joysticks, man-machine interfaces, heavy-duty vehicles, forklifts, robots, wheelchairs, industrial cranes, and more.
Beyond Position Sensor …Battery current monitoring, inverter current sensing, hybrid vehicle battery control systems, and more.
Triaxis Features and Benefits
- First 3D magnetic sensor
- Position (via on-chip computation) or vector output
- Variety of output protocols: Ratiometric analog, PWM, SENT, SPI, I2C
- Enhanced self-diagnostics features for fail-safe operation
- 5V and 3.3V supply voltage
- High thermal stability (up to 160 Deg. C.)
- Immune to dust, dirt, and liquids
- Tolerant to assembly variances thanks to the programmable nature
- Simple, low cost magnet requirements
- Dual mold package enabling PCB free integration available
- Industry standard SOIC8, TSSOP16, and QFN16 packages available