Multi-shield capacitive sensing circuit

A method of making a proximity sensor, comprising:

• providing a capacitive touch controller;
• coupling a first shielding area to a first terminal of the capacitive touch controller;
• coupling a second shielding area to a second terminal of the capacitive touch controller;
• disposing a sensing element over the first shielding area;
• and
• measuring a self-capacitance of the sensing element with the capacitive touch controller while the second shielding area is inactive.

A proximity sensing circuit, comprising:

• a capacitive touch controller;
• a first shielding area coupled to a first shield terminal of the capacitive touch controller;
• a second shielding area coupled to a second shield terminal of the capacitive touch controller;
• and
• a first sensing element disposed over the first shielding area and outside a footprint of the second shielding area.

A capacitive touch controller, comprising:

• a first shield terminal;
• a second shield terminal;
• a shield control module;
• a first multiplexer (MUX) for selectively coupling the first shield terminal or second shield terminal to the shield control module;
• a first sensing terminal;
• a second sensing terminal;
• an analog front-end;
• and
• a second MUX for selectively coupling the first sensing terminal or second sensing terminal to the analog front-end.