Semtech Corporation
TIME-AVERAGED PROXIMITY SENSOR

Abstract:

A proximity sensor for a portable connected wireless device generating an immediate proximity status signal (PROXSTAT, 310) that becomes active when a part of a user's body is close to the proximity sensor, an averaging unit (259) that may include a FIFO buffer, averaging the immediate proximity status flag in a predetermined time window, and a decision unit generating a time-averaged proximity status flag (350) based on an averaged value of the immediate proximity status flag in the time window, for example when the averaged value exceeds a predetermined threshold. In embodiments, the sensor is configured to switch temporarily and repeatedly the time-averaged proximity status flag to an inactive state when the value of the averaged or accumulated value yields an active state of the time-averaged proximity status flag. This feature improves the connectivity when the sensor is used to limit the RF emission of mobile devices.