# US 11,998,948 B2 · Driver circuitry for piezoelectric transducers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,998,948 B2 - Document ID: US11998948B2 - Status: Granted - Kind: B2 - Application number: 16/921,369 - Filed: 2020-07-06 - Published: 2022-01-06 - Granted: 2024-06-04 - Earliest claimed: 2020-07-06 - Assignees: Cirrus Logic, Inc. - Applicants: Cirrus Logic International Semiconductor Ltd. - Inventors: John Paul Lesso; Toru Ido - Web page: https://patentgrep.com/patent/US11998948B2 ## CPC - B06B 1/0261: {taken from a transducer or electrode connected to the driving transducer} - H10N 30/802: {Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits} - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) - H04R 19/00: Electrostatic transducers - B06B 2201/55: Piezoelectric transducer - 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) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract The present disclosure relates to driver circuitry for driving a piezoelectric transducer. The circuitry comprises: a power supply; a reservoir capacitance; switch network circuitry; and control circuitry. The control circuitry is configured to control operation of the switch network circuitry so as to charge the reservoir capacitance from the power supply and to transfer charge between the reservoir capacitance and the piezoelectric transducer. ## Claims ### Claim 1 Circuitry for driving a piezoelectric transducer based on an input signal, the circuitry being configured to receive a supply of power from a power supply, the circuitry comprising: a reservoir capacitance; switch network circuitry; monitoring circuitry configured to monitor a level or magnitude of the input signal and to output a signal indicative of the level or magnitude of the input signal; and control circuitry configured to control operation of the switch network circuitry so as to charge the reservoir capacitance from the power supply and to transfer charge between the reservoir capacitance and the piezoelectric transducer; wherein the control circuitry is further configured to control operation of the switch network circuitry to transfer charge from the power supply to the reservoir capacitance based on the signal indicative of the level of the input signal. ### Claim 2 (depends on 1) Circuitry according to claim 1 wherein a capacitance value of the reservoir capacitance is variable. ### Claim 3 (depends on 1) Circuitry according to claim 1 wherein the circuitry further comprises look-ahead circuitry configured to receive the input signal and to output a signal indicative of the level of the input signal to the control circuitry. ### Claim 4 (depends on 1) Circuitry according to claim 1 wherein the circuitry further comprises envelope detector circuitry configured to receive the input signal and to output a signal indicative of an envelope of the input signal to the control circuitry. ### Claim 5 (depends on 1) Circuitry according to claim 1 wherein the switch network circuitry is configured for coupling to a single terminal of the piezoelectric transducer. ### Claim 6 (depends on 1) Circuitry according to claim 1 wherein the switch network circuitry is configured to be coupled to first and second terminals of the piezoelectric transducer. ### Claim 7 (depends on 1) Circuitry according to claim 1 wherein the power supply is configured to provide an output voltage that varies according to a level of the input signal. ### Claim 8 (depends on 1) Circuitry according to claim 1 wherein the power supply is configured to provide an output voltage that is greater than a voltage supplied to the power supply by a power source. ### Claim 9 (depends on 1) Circuitry according to claim 1 wherein the power supply comprises a switching power supply. ### Claim 10 (depends on 1) Circuitry according to claim 1 wherein the control circuitry is configured to receive a feedback signal indicative of a level of charge of the piezoelectric transducer. ### Claim 11 (depends on 10) Circuitry according to claim 10 wherein the feedback signal is based on a voltage across the piezoelectric transducer. ### Claim 12 (depends on 10) Circuitry according to claim 10, wherein the circuitry comprises one or more inductors, wherein the control circuitry is configured to control operation of the switch network circuitry to transfer charge between the reservoir capacitance and the piezoelectric transducer via one of the one or more inductors, and wherein the feedback signal is based on a current through the one of the one or more inductors. ### Claim 13 (depends on 1) Circuitry according to claim 1 wherein the input signal comprises an audio signal, a haptic waveform or an ultrasonic signal. ### Claim 14 (depends on 1) Circuitry according to claim 1 further comprising commutator circuitry coupled to the switch network circuitry, the commutator circuitry being configured to selectively couple a first or a second terminal of the piezoelectric transducer to an output of the switch network circuitry. ### Claim 15 (depends on 1) A device comprising the circuitry of claim 1. ### Claim 16 (depends on 1) Circuitry according to claim 1 further comprising one or more inductors, wherein the control circuitry is configured to control operation of the switch network circuitry to transfer charge between the reservoir capacitance and the piezoelectric transducer via one of the one or more inductors. ### Claim 17 (depends on 16) Circuitry according to claim 16 wherein the control circuitry is configured to control operation of the switch network circuitry to transfer charge from the power supply to the reservoir capacitance via one of the one or more inductors. ### Claim 18 (depends on 1) Circuitry according to claim 1 wherein the control circuitry is configured to control operation of the switch network circuitry so as to transfer charge directly between the reservoir capacitance and the piezoelectric transducer. ### Claim 19 (depends on 1) Integrated circuitry comprising the circuitry of claim 1. ### Claim 20 (depends on 15) A device according to claim 15, wherein the device comprises a mobile telephone, a tablet or laptop computer, a smart speaker, an accessory device, headphones, earphones or earbuds. ### Claim 21 Circuitry for driving a piezoelectric transducer based on an input signal, the circuitry being configured to receive a supply of power from a power supply, the circuitry comprising: a reservoir capacitance; switch network circuitry; monitoring circuitry configured to monitor a level or magnitude of the input signal and to output a signal indicative of the level or magnitude of the input signal; and control circuitry configured to control operation of the switch network circuitry so as to charge the reservoir capacitance from the power supply based on the signal indicative of the input signal. ### Claim 22 Circuitry for estimating a level of charge on a piezoelectric transducer, the circuitry comprising: an inductor for transferring charge to the piezoelectric transducer from a charge source; control circuitry configured to control transfer of charge to the piezoelectric transducer based on an input signal, wherein the control circuitry is configured to receive an indication of a current through the inductor and an indication of a voltage across the piezoelectric transducer, and wherein the control circuitry is configured to estimate the level of charge on the piezoelectric transducer based on: the indication of the voltage across the piezoelectric transducer when a frequency of the input signal is within a first range, and the indication of the current through the inductor when the frequency of the input signal is within a second range.