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US 2011/0234528 A1Published application
Sample and hold capacitance to digital converter
AssigneeSTMicroelectronics Asia Pacific Pte Ltd
InventorsYannick Guedon, Kien Beng Tan
Life of this patent
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Abstract
A circuit for converting charge measured from a touch screen into a digital signal can include a sample and hold circuit. The sample and hold circuit can sample and integrate a charge from a capacitive sense matrix, and hold a voltage signal representing the measured charge. A sigma delta converter can convert the voltage into a digital value.
Claims20
A circuit for converting a measured charge into a digital signal, the circuit comprising:
- a sample and hold circuit configured to sample a charge from a capacitive sense matrix and hold a signal representing the charge for a first period of time;
- and
- an analog to digital converter that converts the signal into a digital value during the first period of time.
A method of measuring and converting a charge into a digital signal, the method comprising:
- sampling the charge from a capacitive sense matrix;
- integrating the charge to produce a voltage;
- storing the voltage for a first period of time;
- and
- converting the voltage into a digital value during the first period of time.
2 more elements
Dependencies are inferred from the claim text.