Traditional Hall-effect sensors measure the magnetic field perpendicular to the surface of the semiconductor chip. By integrating a planar magnetic disk parallel to the integrated circuit's (IC's) surface, the resulting flux concentrator allows measurements parallel to the surface and provides several advantages. A few critical design factors for the sensor demonstrate its value.
In a typical application, the magnetic field on the shaft is perpendicular to the surface of the chip
The design of Melexis' MLX90316 Hall sensor starts with a pair of Hall-effect elements placed at opposite ends of both the X and Y axes of the CMOS-IC layout. The diameter of a soft magnetic disk is strategically positioned above the Hall elements so that its periphery translates the in-plane magnetic field to a perpendicular magnetic field for the sensor elements. By depositing the disk on the surface of the chip at the wafer level, Melexis minimizes alignment issues.
Because the disk is a soft ferromagnetic material, the magnetic field within and around the disk is fixed, but the field rotates synchronously with the external magnetic field. The addition of the ferromagnetic structure amplifies the external field for greater sensitivity and allows the measurement of both components of the flux density parallel to the chip's surface. Additional circuitry in the CMOS-designed sensor, including a microcontroller (MCU) with a digital-signal processor (DSP) core, amplifies, samples, and converts the two signals into the digital domain. Using a CORDIC (cordinate rotation digital computer) algorithm, the DSP determines the shaft angle. The computed angle is available as an analog output voltage from a ratiometric 12-bit DAC and a 12-bit pulse-width-modulated (PWM) signal with programmable frequency or a digital serial protocol.
The design provides increased accuracy because the measurements are less sensitive to flux-density variations from temperature, aging, or airgap. Among the initial applications that can benefit from this approach are several automotive measurements, such as steering-wheel position and steering torque in electrical power- steering systems, as well as accelerator, brake, and other noncontact position sensors.
Melexis programming unit PTC-04 connected to the supply, ground, and output accesses the internal microcontroller and DSP core to program the MLX90316 for the end application. For a larger image, click here
For 3D printing to make the jump from rapid prototyping to manufacturing, engineers will need to find easier ways to move products from their CAD screens to their printers.
Gigabit and PoE are two networking technologies moving ahead in tandem as industrial users power remote Ethernet devices such as IP security cameras at 1,000 Mbps over existing CAT5 cable.
New versions of BASF's Ecovio line are both compostable and designed for either injection molding or thermoforming. These combinations are becoming more common for the single-use bioplastics used in food service and food packaging applications, but are still not widely available.
From Dell / Intel® New Paradigms in Design Work Scott Hamilton, vertical market strategist for Dell Precision workstations, 5/2/2013 5
Early in my career, I worked as a draftsman and remember the days of drawing on vellum with numbered pencils and Mylar with plastic lead. This was a fun experience in the sense that I ...
I've been using workstations for more than 10 years and love finding ways to get more performance from my system. With demanding professional applications that require more power each ...
A lasting memory from my first job as an engineer in an auto assembly plant is standing on hard concrete at six in the morning, vending-machine coffee clutched in hand, listening to ...
For industrial control applications, or even a simple assembly line, that machine can go almost 24/7 without a break. But what happens when the task is a little more complex? That’s where the “smart” machine would come in. The smart machine is one that has some simple (or complex in some cases) processing capability to be able to adapt to changing conditions. Such machines are suited for a host of applications, including automotive, aerospace, defense, medical, computers and electronics, telecommunications, consumer goods, and so on. This radio show will show what’s possible with smart machines, and what tradeoffs need to be made to implement such a solution.
To save this item to your list of favorite Design News content so you can find it later in your Profile page, click the "Save It" button next to the item.
If you found this interesting or useful, please use the links to the services below to share it with other readers. You will need a free account with each service to share an item via that service.
Tweet This
2 
