Low power capacitive sensor button
First Claim
1. An apparatus comprising:
- a timer circuit configured to generate a repetitive trigger signal having a first frequency;
an oscillator configured to generate a clock signal having a second frequency;
a sensing circuitry block coupled with the timer circuit and the oscillator and configured to, in response to the repetitive trigger signal, detect a change in capacitance associated with an object proximate to a capacitive sensor button by applying an excitation signal to the capacitive sensor button during a measurement period; and
a wake logic coupled with the sensing circuitry block, the wake logic configured to transition a processing unit from a first power consumption state to a second power consumption state in response to the sensing circuitry block detecting the change in capacitance associated with the object proximate to the capacitive sensor button.
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Accused Products
Abstract
Disclosed herein are system, methods, and apparatus for low power capacitive sensors. Apparatus may include a timing block configured to generate a repetitive trigger signal having a first frequency, and further configured to generate a clock signal having a second frequency. Apparatus may also include a sensing block coupled with the timing block and configured to, in response to the repetitive trigger signal, detect a change in capacitance associated with an object proximate to a capacitive sensor button by applying an excitation signal to the capacitive sensor button during a measurement period. Apparatus further include a wake logic block coupled with the sensing block and configured to transition a processing unit from a first power consumption state to a second power consumption state in response to the sensing block detecting the change in capacitance associated with the object proximate to the capacitive sensor button.
19 Citations
20 Claims
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1. An apparatus comprising:
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a timer circuit configured to generate a repetitive trigger signal having a first frequency; an oscillator configured to generate a clock signal having a second frequency; a sensing circuitry block coupled with the timer circuit and the oscillator and configured to, in response to the repetitive trigger signal, detect a change in capacitance associated with an object proximate to a capacitive sensor button by applying an excitation signal to the capacitive sensor button during a measurement period; and a wake logic coupled with the sensing circuitry block, the wake logic configured to transition a processing unit from a first power consumption state to a second power consumption state in response to the sensing circuitry block detecting the change in capacitance associated with the object proximate to the capacitive sensor button. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method comprising:
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generating a repetitive trigger signal; generating an excitation signal having a higher frequency than the repetitive trigger signal; detecting a change in capacitance associated with an object proximate to a capacitive sensor by applying the excitation signal to the capacitive sensor during a measurement period, the measurement period being triggered by a pulse of the repetitive trigger signal; and in response to detecting the change in capacitance associated with the object proximate to the capacitive sensor, transitioning a processing unit from a first power consumption state to a second power consumption state, the second power consumption state being a higher power consumption state than the first power consumptions state. - View Dependent Claims (13, 14, 15)
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16. A system comprising:
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a processing unit; a capacitive sensor; a timer circuit configured to generate a repetitive trigger signal having a first frequency; a low power oscillator block configured to generate a clock signal having a second frequency; a sensing circuitry block coupled with the timer circuit and the oscillator block and configured to initiate a measurement period in response to the repetitive trigger signal, and further configured to detect a presence of an object at the capacitive sensor by applying an excitation signal, based on the clock signal to the capacitive sensor, during the measurement period; and a wake logic coupled with the sensing circuitry block, the wake logic configured to transition the processing unit from a first power consumption state to a second power consumption state in response to the sensing circuitry block detecting the presence of the object at the capacitive sensor. - View Dependent Claims (17, 18, 19, 20)
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Specification