Low power capacitive sensor button

摘要

A capacitance sensing module includes a timer circuit configured to generate a repetitive trigger signal, a low power oscillator block configured to generate a clock signal having a higher frequency than the repetitive trigger signal, a sensing block coupled with the timer circuit and the oscillator block and configured to, in response to the repetitive trigger signal, detect a presence of a conductive object at a capacitive sensor button by applying an excitation signal based on the clock signal to the capacitive sensor button, and a wake logic block coupled with the sensing block and configured to transition a processing unit from a low power consumption state to a high power consumption state in response to the sensing block detecting the presence of the conductive object at the capacitive sensor button.

主权项

1. An apparatus, comprising:
a timer circuit configured to generate a repetitive trigger signal; a low power oscillator block configured to generate a clock signal having a higher frequency than the repetitive trigger signal; a sensing block coupled with the timer circuit and the oscillator block and configured to, in response to the repetitive trigger signal, detect a presence of a conductive object at a capacitive sensor button by applying an excitation signal based on the clock signal to the capacitive sensor button during a measurement period; and a wake logic block coupled with the sensing block and configured to transition a processing unit from a low power consumption state to a high power consumption state in response to the sensing block detecting the presence of the conductive object at the capacitive sensor button.