# US 12,184,272 B2 · Switching transducer driver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,184,272 B2 - Document ID: US12184272B2 - Status: Granted - Kind: B2 - Application number: 18/308,395 - Filed: 2023-04-27 - Published: 2024-10-31 - Granted: 2024-12-31 - Earliest claimed: 2023-04-27 - Assignees: Cirrus Logic, Inc. - Applicants: Cirrus Logic International Semiconductor Ltd. - Inventors: John P. Lesso; Douglas J. W. Macfarlane - Web page: https://patentgrep.com/patent/US12184272B2 ## CPC - H03F 1/02: Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation - H03K 17/687: the devices being field-effect transistors - H03F 3/187: in integrated circuits - H03F 3/2173: {of the bridge type} - H03K 19/0005: {Modifications of input or output impedance} - H03K 19/018585: {programmable} - H03F 2200/03: the amplifier being designed for audio applications - H03F: AMPLIFIERS - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A switching transducer driver operable in: a first mode in which first and second output stage switches are controlled to generate a two-level output signal, wherein an impedance of the first output stage switch is substantially the same as an impedance of the second output stage switch; and a second mode in which the first and second output stage switches and a third switch are controlled to generate a three-level output signal, wherein an impedance of the third switch is substantially greater than the impedance of the first output stage switch and the second output stage switch. ## Claims ### Claim 1 A switching transducer driver operable in: a first mode in which first and second output stage switches are controlled to generate a two-level output signal, wherein an impedance of the first output stage switch is substantially the same as an impedance of the second output stage switch; and a second mode in which the first and second output stage switches and a third switch are controlled to generate a three-level output signal, wherein an impedance of the third switch is substantially greater than the impedance of the first output stage switch and the second output stage switch; wherein the switching transducer driver is operable in a third mode in which an output of the switching transducer driver is clamped to a reference voltage, and wherein the switching transducer driver is configured to operate in the third mode if a parameter of the input signal is less than a second threshold. ### Claim 2 (depends on 1) The switching transducer driver of claim 1, wherein the switching transducer driver is operable at a first frequency in the first mode, and is operable at a second frequency in the second mode. ### Claim 3 (depends on 2) The switching transducer driver of claim 2, wherein the second frequency is lower than the first frequency. ### Claim 4 (depends on 1) The switching transducer driver of claim 1, wherein the first output stage switch and the second output stage switch are implemented using wide bandgap or high electron mobility transistor (HEMT) devices. ### Claim 5 (depends on 1) The switching transducer driver of claim 1, wherein the impedance of the third switch is at least twice the impedance of the first output stage switch and/or the second output stage switch. ### Claim 6 (depends on 1) The switching transducer driver of claim 1, wherein the switching transducer driver comprises control circuitry configured to select between the first mode and the second mode based on a parameter of an input signal to the switching transducer driver. ### Claim 7 (depends on 6) The switching transducer driver of claim 6, wherein the parameter of the input signal comprises a magnitude, level, envelope or volume of the input signal. ### Claim 8 (depends on 6) The switching transducer driver of claim 6, wherein the control circuitry comprises modulator circuitry configured to receive the input signal and a carrier wave signal and to generate a modulated output signal based on the input signal and the carrier wave signal. ### Claim 9 (depends on 8) The switching transducer driver of claim 8, wherein the modulator circuitry comprises: a variable phase shift element configured to generate a phase shifted version of the carrier wave signal; a first comparator configured to generate a first comparator output signal based on a comparison of the input signal and the carrier wave signal; and a second comparator configured to generate a second comparator output signal based on a comparison of the input signal and the phase shifted version of the carrier wave signal, wherein the modulated output signal is based on the first comparator output signal and the second comparator output signal. ### Claim 10 (depends on 9) The switching transducer driver of claim 9, wherein the control circuitry is operative to generate a control signal for controlling a phase shift applied by the variable phase shift element to the carrier wave signal to generate the phase shifted version of the carrier wave signal, wherein the control signal is based on the parameter of the input signal. ### Claim 11 (depends on 10) The switching transducer driver of claim 10, wherein the control signal represents a variable α that controls the phase shift applied by the variable phase shift element, wherein the variable α is based on a comparison of the parameter of the input signal to a threshold such that the variable α is equal to 0 if the parameter of the input signal is equal to or greater than a first threshold, and is equal to 1 if the parameter of the input signal is less than the first threshold. ### Claim 12 (depends on 11) The switching transducer driver of claim 11, wherein a value of α is variable over a continuous range based on the parameter of the input signal, wherein the continuous range is between 0 and an upper limit value which is equal to or less than 1. ### Claim 13 (depends on 8) The switching transducer driver of claim 8, wherein the modulator circuitry comprises open loop modulator circuitry. ### Claim 14 (depends on 1) The switching transducer driver of claim 1, wherein the third switch is of a different device type or technology than the first and second output stage switches. ### Claim 15 (depends on 14) The switching transducer driver of claim 14, wherein the third switch is implemented using one or more MOSFET devices. ### Claim 16 (depends on 1) The switching transducer driver of claim 1, wherein the third switch is implemented as back-to-back coupled switches. ### Claim 17 (depends on 1) A module comprising a substrate on which the third switch and the first and second output stage switches of the switching transducer driver of claim 1 are mounted. ### Claim 18 (depends on 1) A host device comprising the switching transducer driver of claim 1. ### Claim 19 (depends on 18) The host device according to claim 18, wherein the host device comprises a laptop, notebook, netbook or tablet computer, an automotive system, an audio system for a vehicle, a gaming device, a games console, a controller for a games console, a virtual reality (VR) or augmented reality (AR) device, a mobile telephone, a portable audio player, a portable device, an accessory device for use with a laptop, notebook, netbook or tablet computer, a gaming device, a games console a VR or AR device, a mobile telephone, a portable audio player or other portable device. ### Claim 20 A switching transducer driver operable in: a first mode in which first and second output stage switches are controlled to generate a two-level output signal, wherein an impedance of the first output stage switch is substantially the same as an impedance of the second output stage switch; and a second mode in which the first and second output stage switches and a third switch are controlled to generate a three-level output signal, wherein an impedance of the third switch is substantially greater than the impedance of the first output stage switch and the second output stage switch, wherein the switching transducer driver comprises control circuitry configured to select between the first mode and the second mode based on a parameter of an input signal to the switching transducer driver, wherein the control circuitry comprises modulator circuitry configured to receive the input signal and a carrier wave signal and to generate a modulated output signal based on the input signal and the carrier wave signal.