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US 8,710,853 B2Granted
Capacitance sensing
AssigneeInfineon Technologies AG
InventorsMee Hing He, Leela Madhuri Bhaskarabhotla, Arno Rabenstein, Qian Zhao
Life of this patent
Estimating the term…
Abstract
Embodiments related to sensing a capacitance are described and depicted.
Claims23
A microcontroller comprising:
- an analog-to-digital converter to provide a digital value based on an analog input signal from a capacitance, the digital value representing the voltage between electrodes of the capacitance;
- a limit checker to determine whether the digital value is within a predetermined range and to generate a first output signal when the digital value reaches an upper limit of the predetermined range and to generate a second output signal when the digital value reaches a lower limit of the predetermined range, the predetermined range being a programmable predetermined range associated with the limit checker;
- at least a first input connected or connectable to the analog-to-digital converter;
- at least one switch configured to alternately couple the first input to a first potential for charging the capacitance based on applying the second signal to the switch and to couple the first input to a second potential for discharging the capacitance based on applying the first signal to the switch;
- and
- an entity capable to determine a value or a change of the capacitance based on the alternately charging and discharging of the capacitance.
3 more elements
A method for detecting a change of a capacitance comprising:
- feeding a signal from a first input connected to the capacitance to an analog-to-digital converter;
- repeatedly generating a switching signal based on a digital output signal of the analog-to-digital converter, the repeatedly generating act including
- repeatedly generating a digital value based on the signal at the input of the analog-to-digital converter,
- determining whether the digital value is within a predetermined range,
- generating the switching signal based on the determining whether the digital value is within the predetermined range, the predetermined range being a programmable predetermined range;
- switching between charging the capacitance and discharging the capacitance based on the switching signal;
- and
- detecting the change of the capacitance based on the switching between charging and discharging.
5 more elements
A method for sensing a capacitance comprising:
- programming values of an upper and lower threshold limit.
- generating a switching signal when an output of an analog-to-digital converter reaches one of the programmed values;
- switching between charging a capacitance coupled to an input of the analog-to-digital converter and discharging the capacitance, the switching being based on the switching signal;
- sensing the capacitance based on the switching between charging and discharging.
1 more element
A device comprising:
- an oscillator circuit to provide an oscillation used for determining a value or a change of a capacitance, the oscillator circuit comprising:
- a circuit to provide a digital value based on an analog input signal;
- a limit checker to determine whether the digital value is within a programmed range and to generate an output signal when the digital value is determined to be out of the predetermined range, the predetermined range being a programmable predetermined range associated with the limit checker;
- at least a first input coupled to an input of the analog-to-digital converter;
- at least one switch configured to alternately connect an electrode of the capacitance to a first potential and to a second potential to alternately charge and discharge the capacitance via at least one impedance, the at least one switch being controlled based on the output signal of the limit checker.
2 more elements
Dependencies are inferred from the claim text.