# US 10,873,020 B2 · Piezoelectric sensing apparatus and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,873,020 B2 - Document ID: US10873020B2 - Status: Granted - Kind: B2 - Application number: 15/671,252 - Filed: 2017-08-08 - Published: 2019-02-14 - Granted: 2020-12-22 - Earliest claimed: 2017-08-08 - Assignees: Texas Instruments Incorporated - Applicants: Texas Instruments Incorporated - Inventors: Wei-Yan Shih; Sudhanshu Khanna; Michael Zwerg; Juergen Luebbe; Gregory Allen North; Steven C. Bartling; Leah Trautmann; Scott Robert Summerfelt - Web page: https://patentgrep.com/patent/US10873020B2 ## CPC - H10N 30/40: with electrical input and electrical output, e.g. functioning as transformers - B06B 1/06: operating with piezoelectric effect or with electrostriction (piezoelectric or electrostrictive devices per se H10N30/00) - G01H 11/08: using piezoelectric devices - H10N 30/302: {Sensors} - H10N 30/802: {Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits} - H10N 30/87: Electrodes or interconnections, e.g. leads or terminals - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R) - G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES ## Abstract A piezoelectric sensor with: (i) a capacitive element, comprising piezoelectric material; (ii) a pre-conditioning circuit, comprising circuitry for establishing a polarization of the capacitive element in a polarizing mode; and (iii) signal amplification circuitry for providing a piezoelectric-responsive output signal, in response to charge across the capacitive element in a sensing mode. ## Claims ### Claim 1 A piezoelectric sensor, comprising: an integrated circuit comprising: a substrate; a capacitive element affixed relative to the substrate, the capacitive element comprising piezoelectric material; a preconditioning circuit affixed relative to the substrate, the preconditioning circuit configured to establish a polarization of the capacitive element in a polarizing mode; and signal amplification circuitry affixed relative to the substrate, the signal amplification circuitry configured to provide a piezoelectric-responsive output signal responsive to a charge across the capacitive element in a sensing mode. ### Claim 2 A piezoelectric sensor, comprising: a capacitive element comprising serially-connected piezoelectric capacitors; a preconditioning circuit configured to establish a polarization of the capacitive element in a polarizing mode; and signal amplification circuitry configured to provide a piezoelectric-responsive output signal responsive to a charge across the capacitive element in a sensing mode. ### Claim 3 (depends on 2) The sensor of claim 2, wherein the preconditioning circuit is configured to establish a same polarization of the serially-connected piezoelectric capacitors at a separate time per capacitor. ### Claim 4 (depends on 2) The sensor of claim 2, wherein the preconditioning circuit is configured to establish a same polarization of the serially-connected piezoelectric capacitors at a separate time per capacitor and along a sequential direction in the serially-connected piezoelectric capacitors. ### Claim 5 (depends on 2) The sensor of claim 2, wherein the preconditioning circuit is configured to: establish a polarization polarity and a first polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along a first sequential direction in the serially-connected piezoelectric capacitors; and maintain the polarization polarity, and establish a second polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along the first sequential direction, in which the second polarization magnitude differs from the first polarization magnitude. ### Claim 6 (depends on 5) The sensor of claim 5, wherein: the preconditioning circuit is configured to apply a non-zero voltage to the serially-connected piezoelectric capacitors and the sensor further comprises circuitry configured to change the non-zero voltage to a zero voltage at a separate time per capacitor along a second sequential direction opposite the first sequential direction. ### Claim 7 (depends on 5) The sensor of claim 5, wherein: the serially-connected piezoelectric capacitors consist of an integer N of piezoelectric capacitors; and 3≤N≤64. ### Claim 8 (depends on 5) The sensor of claim 5, wherein: the serially-connected piezoelectric capacitors consist of an integer N of piezoelectric capacitors; the preconditioning circuit comprises an integer number N+1 signal paths coupled to the capacitive element; and the N+1 signal paths are configured to couple a poling signal to respective different terminals in the serially-connected piezoelectric capacitors. ### Claim 9 (depends on 8) The sensor of claim 8 wherein the N+1 signal paths comprise respective switches configured to be enabled during the polarizing mode and to be disabled during the sensing mode. ### Claim 10 (depends on 9) The sensor of claim 9, wherein: the serially-connected piezoelectric capacitors are connected to a reference voltage during the sensing mode; and the switch comprises: a first transistor comprising a drain connected to a respective terminal in the serially-connected piezoelectric capacitors; a second transistor configured to bias a backgate of the first transistor to the reference voltage during the sensing mode; and a third transistor configured to bias a source of the first transistor to the reference voltage during the sensing mode. ### Claim 11 (depends on 2) The sensor of claim 2, wherein the preconditioning circuit is configured to: establish a first polarization polarity and a first polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along a first sequential direction in the serially-connected piezoelectric capacitors; maintain the first polarization polarity, and establish a second polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along the first sequential direction; establish a second polarization polarity and a third polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along a second sequential direction in the serially-connected piezoelectric capacitors, in which the second polarization polarity is opposite the first polarization polarity, and the second sequential direction is opposite the first sequential direction; and maintain the second polarization polarity, and establish a fourth polarization magnitude of the serially-connected piezoelectric capacitors at a separate time per capacitor and along the second sequential direction in the serially-connected piezoelectric capacitors. ### Claim 12 (depends on 11) The sensor of claim 11, wherein the preconditioning circuit is configured to: apply a non-zero voltage along the second sequential direction in the serially-connected piezoelectric capacitors; and the sensor further comprises circuitry configured to change the non-zero voltage to a zero voltage at a separate time per capacitor along the second sequential direction in the serially-connected piezoelectric capacitors. ### Claim 13 (depends on 11) The sensor of claim 11, wherein: the serially-connected piezoelectric capacitors consist of an integer N of piezoelectric capacitors; and 3≤N≤64. ### Claim 14 (depends on 11) The sensor of claim 11, wherein the second polarization magnitude equals the fourth polarization magnitude. ### Claim 15 (depends on 11) The sensor of claim 11, wherein the second polarization magnitude does not equal the fourth polarization magnitude. ### Claim 16 (depends on 11) The sensor of claim 11, wherein: the serially-connected piezoelectric capacitors consist of an integer N of piezoelectric capacitors; the preconditioning circuit comprises an integer number N+1 signal paths coupled to the capacitive element; and the N+1 signal paths are configured to couple a poling signal to respective different terminals in the serially-connected piezoelectric capacitors. ### Claim 17 (depends on 16) The sensor of claim 16, wherein the N+1 signal paths comprise respective switches configured to be enabled during the polarizing mode and to be disabled during the sensing mode. ### Claim 18 (depends on 17) The sensor of claim 17, wherein: the serially-connected piezoelectric capacitors are connected to a reference voltage during the sensing mode; and the switch comprises: a first transistor comprising a drain connected to a respective terminal in the serially-connected piezoelectric capacitors; a second transistor configured to bias a backgate of the first transistor to the reference voltage during the sensing mode; and a third transistor configured to bias a source of the first transistor to the reference voltage during the sensing mode. ### Claim 19 A method of operating a piezoelectric sensor, the sensor comprising a capacitive element, comprising serially-connected piezoelectric capacitors, the method comprising: before sensing, establishing a polarization of the capacitive element in a polarizing mode by polarizing the serially-connected piezoelectric capacitors, one at a time; and after establishing the polarization, sensing a response by amplifying a piezoelectric-responsive output signal responsive, to a charge across the capacitive element. ### Claim 20 (depends on 19) The method of claim 19 wherein the establishing comprises polarizing the serially-connected piezoelectric capacitors along a sequential direction in the serially-connected piezoelectric capacitors.