CN0095: Using the AD7150 Capacitance-to-Digital Converter (CDC) for Proximity Sensing Applications

CIRCUIT FUNCTION AND BENEFITS
The circuit described in this document provides the basis for developing a proximity sensing application using the AD7150 capacitance-to-digital converter (CDC).

The AD7150 CDC measures the capacitance between two electrodes and compares its measurement result with a threshold value, which can be either fixed or dynamically adjusted by the on-chip adaptive threshold algorithm engine.

If the input capacitance is altered, for example, by the presence of a hand, an output flag is set to indicate that a threshold has been exceeded, thus indicating proximity.

This on-chip adaptive threshold algorithm engine also enables the AD7150 to adapt to slow changes in the sensing capacitance, which may be caused by environmental changes, such as humidity or temperature, without losing the capability of proximity sensing.

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