# US 12,009,675 B2 · Apparatus and methods for real-time resonance adaptation for power receiver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,009,675 B2 - Document ID: US12009675B2 - Status: Granted - Kind: B2 - Application number: 18/048,333 - Filed: 2022-10-20 - Published: 2023-07-06 - Granted: 2024-06-11 - Earliest claimed: 2020-04-22 - Assignees: The Regents of the University of California - Applicants: The Regents of the University of California - Inventors: Hongming Lyu; Aydin Babakhani - Web page: https://patentgrep.com/patent/US12009675B2 ## CPC - H02J 50/12: of the resonant type - H02J 50/005: {Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices} - H02J 50/20: using microwaves or radio frequency waves - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - A61N 1/3787: {from an external energy source} - H02J 2105/46: Medical devices, medical implants or life supporting devices - H04B 1/71635: {Transmitter aspects (H04B1/7174 takes precedence)} - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B) - H04B: TRANSMISSION ## Abstract Wirelessly powered receiver system and sensors are described. In an embodiment, the power receiver system, includes an inductive coil that receives wireless power from an external transmitter, a capacitor bank that optimizes power transfer to an energy harvesting device, and a power-receiving frontend RF-DC rectifier with a periodically enabled closed feedback loop that adapts settings of the capacitor bank in real-time to adapt to changes on the inductive coil to maximize power transfer efficiency. ## Claims ### Claim 1 A power receiver system, comprising: an inductive coil configured to receive wireless power from an external transmitter; a resonance capacitor comprising a capacitor bank having an input coupled to the inductive coil, and a plurality of capacitors configured to be selectively included in one or more of a plurality of capacitor-bank settings; a power-receiving frontend RF-DC rectifier coupled to the capacitor bank; and an amplitude detector having an input coupled to the input of the capacitor bank and an output, the amplitude detector configured to provide measurements of the input of the capacitor bank, and a resonance compensator having outputs coupled to the capacitor bank and an input coupled to the output of the amplitude detector, the resonance compensator configured to: sample the measurements of the input of the capacitor bank through the amplitude detector; and adapt the resonance capacitor by selecting an optimal capacitor-bank setting based on the measurements of the input of the capacitor bank in real-time to adapt to changes on the inductive coil. ### Claim 2 (depends on 1) The power receiver system of claim 1, wherein the power-receiving frontend RF-DC rectifier comprises a Dickson-stage passive rectifier and the capacitor bank comprises a binary-weighted capacitor bank implemented in parallel with the Dickson-stage passive rectifier. ### Claim 3 (depends on 1) The power receiver system of claim 1, wherein the measurements of the input of the capacitor bank are in the analog domain. ### Claim 4 (depends on 1) The power receiver system of claim 1, wherein the capacitor bank is a 6-bit capacitor bank and the resonance compensator is configured to periodically adapt the resonance capacitor based on the measurements of the input of the capacitor bank using a successive-approximation-resonance-tuning process. ### Claim 5 (depends on 1) The power receiver system of claim 1, wherein the resonance compensator is configured to adapt the resonance capacitor a plurality of times per second. ### Claim 6 (depends on 1) The power receiver system of claim 1, wherein the resonance compensator comprises: latch circuitry having an output and a plurality of inputs, wherein the latch circuitry is configured to output a swing measurement corresponding to a change in the output of the amplitude detector due to a change in capacitor-bank setting, and logic circuitry coupled to the output of the latch circuitry. ### Claim 7 (depends on 6) The power receiver system of claim 6, wherein the resonance compensator is configured to select an optimal capacitor-bank setting by being further configured to: obtain a plurality of swing measurements, identify a maximum swing measurement from the plurality of swing measurements, and select the capacitor-bank setting associated with the maximum swing measurement as the optimal capacitor-bank setting. ### Claim 8 (depends on 6) The power receiver system of claim 6, wherein the resonance compensator further comprises a plurality of hold capacitors, each selectively coupled to the output of the amplitude detector, wherein each of the plurality of inputs of the latch circuitry is selectively coupled to a respective one of the plurality of hold capacitors. ### Claim 9 (depends on 6) The power receiver system of claim 6, wherein the change in capacitor-bank settings comprises a change from a first capacitor-bank setting to a second capacitor-bank setting that is consecutive in time with the first capacitor-bank setting. ### Claim 10 (depends on 1) The power receiver system of claim 1, wherein the resonance capacitor is characterized by an offset, and an impedance of the inductive coil is approximately symmetric against the offset. ### Claim 11 (depends on 1) The power receiver system of claim 1, further comprising a transmitter configured to transmits information to an external controller. ### Claim 12 (depends on 11) The power receiver system of claim 11, wherein: the information comprises a real-time harvested voltage reading, the transmitter is an ultra-wideband impulse radio (IR-UWB) transmitter as a back telemetry for output voltage regulation, and an output voltage from the IR-UWB transmitter is regulated based on back telemetry transmitting the real-time harvested voltage reading. ### Claim 13 (depends on 1) The power receiver system of claim 1, further comprising: a coarse bandgap reference (BGR-course) and a local low-dropout regulator (LDO) coupled to the output of the power-receiving frontend RF-DC rectifier and that generates a voltage supply for circuitry; and a fine bandgap reference (BGR-fine) coupled to the output of the LDO and that generates a stable voltage reference. ### Claim 14 A wirelessly powered sensor chip configured for placement relative to a surrounding environment, comprising: an inductive coil configured to receives wireless power from an external transmitter; a capacitor bank having an input coupled to the inductive coil, the capacitor bank comprising a plurality of capacitors configured to be selectively included in one or more of a plurality of capacitor-bank settings; a power-receiving frontend RF-DC rectifier coupled between the capacitor bank; and an amplitude detector having an input coupled to the input of the capacitor bank and an output, the amplitude detector configured to provide measurements of the input of the capacitor bank, and a resonance compensator having outputs coupled to the capacitor bank and an input coupled to the output of the amplitude detector, the resonance compensator configured to: sample the measurements of the input of the capacitor bank through the amplitude detector; select an optimal capacitor-bank setting based on the measurements of the input of the capacitor bank in real-time to adapt to the surrounding environment; and a transmitter configured to transmit information related to the capacitor-bank settings and voltage readings to an external controller. ### Claim 15 (depends on 14) The wirelessly powered sensor chip of claim 14, further comprising: an analog-to-digital convertor having an input coupled to the output of the power-receiving frontend RF-DC rectifier, and an output, wherein the analog-to-digital convertor is configured to provide the voltage readings; and a serializer and packetizer having an input coupled to the output of the analog-to-digital convertor, and an output coupled to the transmitter, wherein operations of the resonance compensator, the analog-to-digital convertor, and the serializer and packetizer are duty cycled. ### Claim 16 (depends on 15) The wirelessly powered sensor chip of claim 15, wherein operations of the resonance compensator, the analog-to-digital convertor, and the serializer and packetizer occur a plurality of time per second. ### Claim 17 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein the capacitor-bank settings are used by the external controller to determine a type of material in the surrounding environment. ### Claim 18 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein changes to the capacitor-bank settings and are used by the external controller to detect near-field changes in the surrounding environment. ### Claim 19 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein changes to a voltage reading without changes to the capacitor-bank settings are used by the external controller to detect far-field changes in the surrounding environment. ### Claim 20 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein the capacitor bank is a 6-bit capacitor bank and the resonance compensator is configured to periodically adapt the capacitor bank based on the measurements of the input of the capacitor bank using a successive-approximation-resonance-tuning process. ### Claim 21 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein the resonance compensator comprises: latch circuitry having an output and a plurality of inputs, wherein the latch circuitry is configured to output a swing measurement corresponding to a change in the output of the amplitude detector due to a change in capacitor-bank setting, and logic circuitry coupled to the output of the latch circuitry. ### Claim 22 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein the capacitor bank is characterized by an offset, and an impedance of the inductive coil is approximately symmetric against the offset. ### Claim 23 (depends on 14) The wirelessly powered sensor chip of claim 14, wherein: the information comprises a real-time harvested voltage reading, the transmitter is an ultra-wideband impulse radio (IR-UWB) transmitter as a back telemetry for output voltage regulation, and an output voltage from the IR-UWB transmitter is regulated based on back telemetry transmitting the real-time harvested voltage reading. ### Claim 24 A sensor system comprising: a wirelessly powered sensor chip configured for placement relative to a surrounding environment, comprising: an inductive coil configured to receives wireless power from an external transmitter; a capacitor bank having an input coupled to the inductive coil, the capacitor bank comprising a plurality of capacitors configured to be selectively included in one or more of a plurality of capacitor-bank settings; a power-receiving frontend RF-DC rectifier coupled between the capacitor bank; and an amplitude detector having an input coupled to the input of the capacitor bank and an output, the amplitude detector configured to provide measurements of the input of the capacitor bank, and a resonance compensator having outputs coupled to the capacitor bank and an input coupled to the output of the amplitude detector, the resonance compensator configured to: sample the measurements of the input of the capacitor bank through the amplitude detector, and select an optimal capacitor-bank setting based on the measurements of the input of the capacitor bank in real-time to adapt to the surrounding environment; a transmitter configured to transmit information related to the capacitor-bank settings and voltage readings; and a controller configured to receive and process the transmit information related to the capacitor-bank settings and voltage readings to determine as aspect of the surrounding environment. ### Claim 25 (depends on 24) The sensor system of claim 24, wherein the controller is configured to determine a type of material in the surrounding environment based on the capacitor-bank settings. ### Claim 26 (depends on 24) The sensor system of claim 24, wherein the controller is configured to detect near-field changes in the surrounding environment based on changes to the capacitor-bank settings. ### Claim 27 (depends on 24) The sensor system of claim 24, wherein the controller is configured to detect far-field changes in the surrounding environment based on changes to a voltage reading without changes to the capacitor-bank settings.