Touch sensing method and apparatus

摘要

A method for measuring for generating a touch capacitance measurement is provided. Gain and offset control signals are generated, where the gain and offset control signals are adjusted to compensate for base capacitance of a touch sensor. The gain control signal is applied to a touch sensor during a first phase of a clock signal, and the offset control signal is applied to an output circuit during a second phase of the clock signal. The output circuit is coupled to the touch sensor during the second phase of the clock signal. The touch capacitance measurement is generated by compensating for the base capacitance with the gain and offset control signals, and a gain is applied to the touch capacitance measurement.

主权项

1. An apparatus comprising:
an interface that is configured to communicate with a touch sensor having a base capacitance; and a capacitance-to-voltage converter that receives a clock signal and that is coupled to the interface, wherein the capacitance-to-voltage converter generates gain control and offset signals, and wherein the capacitance-to-voltage converter is configured to apply the gain control signals to the touch sensor during a first phase of the clock signal, and the gain and offset control signals are adjusted to compensate for the base capacitance, and wherein the capacitance-to-voltage converter uses the gain and offset control signals during a second phase of the clock signal to compensate for the base capacitance and provide a touch capacitance measurement.