Patent ID: 11054938

Abstract:
A capacitance-sensing circuit may include a channel input associated with measuring a capacitance of a unit cell of a capacitive sense array. The capacitance-sensing circuit may also include a capacitive hardware baseliner that is coupled to the channel input. The capacitive hardware baseliner includes a programmable baseline resistor, and a buffer with an input coupled to the programmable baseline resistor and an output coupled to the channel input. The capacitive hardware baseliner generates a baseline current based on a time constant of the channel input associated with the measuring of the capacitance of the element of the capacitive sense array using the programmable baseline resistor. The capacitive hardware baseliner provides the baseline current at the channel input to provide a charge for a sense capacitor. A change in the charge of the sense capacitor is provided by the baseline current indicating a presence of a touch object proximate to the element.