Each time you climb into your car, you enter a world of magnetic sensing, with tiny sensors reporting whether the doors are closed and seat belts buckled properly. Sensors also automatically guide seats into place, help open windows, turn steering column switches on and off, and track how you turn the steering wheel or press the accelerator.
Several magnetic sensors are located, under the hood, detecting speed and position in the car’s engine, transmission and electric motors. Other sensors monitor fluid levels, track body and wheel position, perform a number of safety checks, and sense currents for a variety of electrical feedback and measurement functions.
A new automobile today may have as many as 70 magnetic sensors to enhance operation, safety and convenience. More are being added all the time due to technology advancements that deliver greater accuracy and reliability in smaller sizes with lower cost.
The same trend can be observed in the electronic and electromechanical world in general. In addition to widespread use in vehicles, magnetic sensors find application in equipment including industrial motors and robots, medical systems, office machines, home appliances, and even handheld tablets and cellphones. Like so many other semiconductor devices that make the modern world go round, magnetic sensors are invisible to end users but indispensable for many of the functions that we have come to take for granted. Figure 1 lists some of these uses.
What enables the ubiquity of magnetic sensors today is their small size and affordability. Semiconductor manufacturers have applied advanced production techniques to enable analog integrated circuit (IC) products that include sensors, bringing the advantages of miniaturization to what were once space-consuming devices. At the same time, the cost of the permanent magnets integrated within some magnetic sensors has dropped, helping push the trend toward affordability that comes with advanced manufacturing, as well as increasing functionality. The need for improved reliability, safety and accuracy has motivated end product developers to take advantage of the inexpensive magnetic sensors that are now available on chips along with other circuitry. As a result, applications are mushrooming, with a market estimated to pass $2 billion and 20 billion units in the next five years, with the majority in the automotive segment.
Texas Instruments (TI) devotes significant development effort to magnetic sensing. TI’s portfolio of magnetic sensors gives equipment manufacturers an array of options for their varied application needs. The company’s advanced analog process technology makes possible the on-chip integration of complete sensing solutions that include both the sensing element and other circuitry. TI process innovation enabled the industry’s first integrated fluxgate magnetic sensors for extremely high-precision measurement. For the growing world of magnetic sensing, the company’s technology continues to drive the development of solutions for an ever-expanding range of end uses.