Thirty-five years and 11 billion miles...
Now that’s reliability.
Made in the USA.
resulting in better sensitivity levels.
Since differential detection offers much better signal-to-noise ratio over single detection, it permits operation using
a gloved hand (as shown in Figure 6) something that can be
highly advantageous in industrial applications or outdoors in
the winter. Furthermore, differential sensor deployments are
less susceptible to electro-magnetic interference (EMI), making them better suited to demanding application scenarios,
such as automotive and industrial (Figure 7).
The superior noise rejection supported by differential
sensing allows more flexiblity in the sensor pattern utilized.
Long routing sensor patterns can be tolerated, as the CV
amplifier can cancel out Cp through negative feedback. The
improved noise rejection offered by this approach also means
that it is possible to amplify small differences in capacitance.
This allows simplified sensor implementations to be achieved
without the need for adhesive between the overlay and sensor PCB resulting in substantial cost savings.
As engineers begin to recognize the full appeal of contem-
Figure 6: Operation of touch switch while wearing gloves.
Figure 7: Superior noise performance of mutual differential sensing.
porary touch switch solutions, these devices are certain to
see greater uptake and their true potential will be realized.
It is clear however that ensuring the suitability of sensing technology utilized can have major implications on the
effectiveness of the user interface that results. A wide range
of factors and design issues, including power consumption,
susceptibility to EMI, response time, available engineering
resources, time-to-market, and system integration, need to be
given extensive consideration when looking to deploy touch