Multi-shield capacitive sensing circuit

摘要

A proximity sensor includes a capacitive touch controller. A first shielding area is coupled to a first shield terminal of the capacitive touch controller. A second shield area is coupled to a second shield terminal of the capacitive touch controller. A first sensing element is disposed adjacent to the first shielding area. The first sensing element is coupled to a first sensing terminal of the capacitive touch controller. A second sensing element is disposed adjacent to the second shielding area. The second sensing element is coupled to a second sensing terminal of the capacitive touch controller. The capacitive touch controller is configured to associate the first sensing element with the first shielding area. A self-capacitance of the first sensing element is measured while the second shielding area is inactive. The self-capacitance of the first sensing element is measured at a first frequency.

主权项

1. A method of making a proximity sensor, comprising:
providing a capacitive touch controller; coupling a first shielding area to a first shield terminal of the capacitive touch controller; coupling a second shielding area to a second shield terminal of the capacitive touch controller; disposing a first sensing element directly over the first shielding area and outside a footprint of the second shielding area; disposing a second sensing element directly over the second shielding area and outside a footprint of the first shielding area; configuring the capacitive touch controller to associate the first shielding area with the first sensing element; and configuring the capacitive touch controller to associate the second shielding area with the second sensing element.