Aisin Seiki Kabushiki Kaisha

Kazunori Sugimura

Hisashi Inaba

Masahiro Hagimoto

Provided is a capacitance detection apparatus capable of effectively discriminating between an external factor due to e.g. water drops and a human-induced operation and allowing detection of occurrence of the human-induced operation with a simple arrangement. The apparatus alternately executes a first switching control process and a second switching control process, the first and second switching control processes executing a second switch operation with different charging periods from each other. In each of the first and second switching control processes, the number of repetition times of the second switch operation is counted until the potential of a terminal of a reference capacitance changes to a set potential. Based on the number of repetition times in at least one of the two switching control processes, presence/absence of change in determined capacitance (i.e. capacitance to be determined) is determined and based on the numbers of repetition times in the two control processes, it is determined whether the change in the determined capacitance is due to an event of detection interest or not.

Growing community of inventors

Toyota, Japan

Kazunori Sugimura