Multichannel capacitive sensor device
AssigneeSemtech Corporation
InventorsChaouki Rouaissia, Pascal Monney
Life of this patent
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Abstract
A capacitive sensor with a plurality of sense inputs connectable to capacitive sense electrodes and a common reference input, each sense input and the reference input can be put in a measure state, in a ground state, or in a shield state. The sensor can be equipped with external reference capacitors between each of the sense input and the common reference terminal. The reference capacitor can be read individually by selectively pulling one of the input terminals to ground and driving the other to be equipotential with the reference input.
Claims14
A capacitive sensor device comprising a capacitance-measuring circuit, a plurality of sense inputs and a reference input, each sense input being connectable to a sense electrode, the capacitive sensor device being configured, in a first measurement mode, for driving the reference input to be equipotential with one of the sense inputs that is measured by the capacitance-measuring circuit and determine a value of the capacitance seen by the sense input that is measured unaffected by any capacitance between the sense input that is measured and the reference input, and, in a second measurement mode, for measuring the capacitance seen at the reference input with the capacitance-measuring circuit while holding one sense input to ground and driving other sense inputs to be equipotential with the reference input, determining a value of the reference capacitor connected between the reference input and the sense input that is held to ground unaffected by any capacitance between the reference input and sense inputs that are driven to be equipotential to the reference input.
Dependencies are inferred from the claim text.