METHODS AND APPARATUS FOR A CAPACITIVE SENSOR

摘要

Various embodiments of the present technology may comprise methods and apparatus for increased sensitivity of a capacitive proximity sensor. The method and apparatus may comprise additional external capacitors coupled in parallel with internal variable capacitors to increase the effective capacitance of a detection circuit allowing for a larger sensing element, and therefore a stronger sensing field, without increasing the applied voltage or the internal capacitance of the proximity sensor. In alternative embodiments, the methods and apparatus may be configured to operate as one of a transmission electrode and a reception electrode to increase the strength of the sensing field.

主权项

1. A capacitive proximity sensor, comprising:
a sensing element, comprising:
a first and second electrode, wherein the first and second electrodes form a first sensing capacitor;a first reference capacitor;a first external capacitor coupled in series with the first sensing capacitor at a first node; anda second external capacitor coupled in series with the reference capacitor at a second node; an integrated circuit electrically connected to the sensing element, comprising:
a first variable capacitor coupled in parallel with the first external capacitor;a second variable capacitor coupled in parallel with the second external capacitor; anda differential amplifier; and a voltage source coupled to the first external capacitor, the second external capacitor, the first variable capacitor and the second variable capacitor.