Piezo-electric sensor reset
AssigneeTexas Instruments Incorporated
InventorsMichael Zwerg, Sudhanshu Khanna, Steven C. Bartling, Brian Elies, Krishnasawamy Nagaraj, Wei-Yan Shih
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Abstract
In described examples, each node between adjacent capacitive elements of a stack of series-coupled capacitive elements is biased during a reset mode, where each of the capacitive elements includes piezoelectric material. A strain-induced voltage is generated across each of the capacitive elements. Each of the strain-induced voltages is combined to generate a piezoelectric-responsive output signal during a sensing mode at a time different from the time of the reset mode.
Claims20
Apparatus, comprising:
- a first stack of capacitive elements coupled in series, wherein each of the capacitive elements comprises piezoelectric material;
- a pre-conditioning circuit, including circuitry for biasing in a reset mode each node between adjacent capacitive elements of the first stack;
- and
- signal amplification circuitry for generating a piezoelectric-responsive output signal in response to charge developed across the first stack in a sensing mode during a time different from the time of the reset mode.
A circuit, comprising:
- a first stack that includes a first and second capacitive element coupled in series, wherein the first and second capacitive elements comprise piezoelectric material, wherein the first and second capacitive elements are coupled to a first stack node;
- a first transistor that includes an output terminal coupled to the first stack node, wherein the first transistor is arranged to couple a reference voltage to the first stack node during a reset mode and is arranged to isolate the first stack node from leakage of the first transistor during a sensing mode;
- and
- signal amplification circuitry arranged to generate a piezoelectric-responsive output signal in response to charge developed across the first stack during the sensing mode at a time different from the time of the reset mode.
A method, comprising:
- biasing in a reset mode each node between adjacent capacitive elements of a first stack, wherein the first stack includes capacitive elements coupled in series, wherein each of the capacitive elements comprises piezoelectric material;
- generating a strain-induced voltage across each of the capacitive elements;
- and
- combining the strain-induced voltages to generate a piezoelectric-responsive output signal during a sensing mode at a time different from the time of the reset mode.
Dependencies are inferred from the claim text.