# US 2017/0288467 A1 · In-Band Signaling Within Wireless Power Transfer Systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2017/0288467 A1 - Document ID: US20170288467A1 - Status: Published application - Kind: A1 - Application number: 15/626,989 - Filed: 2017-06-19 - Published: 2017-10-05 - Earliest claimed: 2015-09-28 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: STEPHEN HRINYA; PARIN PATEL - Web page: https://patentgrep.com/patent/US20170288467A1 ## CPC - H02J 50/12: of the resonant type - H02J 7/42: with electronic devices having internal batteries, e.g. mobile phones - H02J 50/80: involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices - H04B 5/266: {One coil at each side, e.g. with primary and secondary coils} - H04B 5/79: for data transfer in combination with power transfer - H04B 5/24: Inductive coupling - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - H04B: TRANSMISSION ## Abstract Systems and methods for in-band communication across a wireless power interface from a load device to a source device. The load device selectively modifies the timing of switches within a voltage rectifier coupled to an output of a receive coil within the load device that receives power from a transmit coil within the source device. The source device detects changes in the power transfer (or in the relative timing of a voltage or a current) as digital information received from the load device. ## Claims ### Claim 1 (canceled) ### Claim 2 A method of transmitting data from a load device to a source device in a wireless power transfer system, the method comprising: determining, by the load device, an update to be communicated from the load device to the source device as a data signal; wirelessly transferring power from the source device to the load device; and desynchronizing, by the load device, a timing of a rectifier in the load device according to a pattern corresponding to the data signal. ### Claim 3 (depends on 2) The method of claim 2, wherein: the rectifier comprises a switch; and modifying the timing of the rectifier comprises delaying a turn off the switch. ### Claim 4 (depends on 3) The method of claim 3, wherein delaying the turn off of the switch comprises delaying a turn off until current through the switch reverses. ### Claim 5 (depends on 3) The method of claim 3, wherein delaying the turn off of the switch suppress a voltage spike associated with current conduction through a diode within the load device. ### Claim 6 (depends on 5) The method of claim 5, wherein the diode is one of: a body diode of the switch; or a Schottky diode coupled across a source and a drain of the switch. ### Claim 7 (depends on 2) The method of claim 2, wherein the update comprises an indication that a battery within the load device is charged. ### Claim 8 (depends on 2) The method of claim 2, wherein the update comprises authentication information. ### Claim 9 (depends on 2) The method of claim 2, wherein the update comprises executable instructions received by a processor of the source device. ### Claim 10 (depends on 2) The method of claim 2, wherein the update comprises temperature information corresponding to a temperature of the load device. ### Claim 11 A method for updating a source device from a load device in a wireless power transfer system, the method comprising: receiving, by the load device, an update to be communicated from the load device to the source device as a data signal; wirelessly transmitting power from the source device to the load device; desynchronizing, by the load device, a rectifier of the load device based on the digital signal; determining, by the source device, that a current threshold crossing has occurred within an electronic element of the source device; recording, by the source device, a digital bit based on the current threshold crossing; and buffering, by the source device, the digital bit as a portion of the data signal. ### Claim 12 (depends on 11) The method of claim 11, wherein; the source device comprises an inverter; and the operation of determining that the current threshold crossing has occurred comprises monitoring a switch of the inverter for a threshold crossing in current. ### Claim 13 (depends on 11) The method of claim 11, wherein the update comprises a temperature of the load device. ### Claim 14 (depends on 11) The method of claim 11, wherein the update comprises executable instructions for a processor of the source device. ### Claim 15 A wireless power transfer system, comprising: a source device comprising: an inverter; a transmit coil coupled to the inverter; and a first processor configured to monitor current in the inverter; and a load device comprising: a receive coil magnetically coupled to the transmit coil; a rectifier coupled to the receive coil and comprising a switch; and a second processor coupled to the switch and configured to: determine an executable instruction to be communicated from the load device to the source device as a data signal; and delay of a turn off of the switch based on the data signal. ### Claim 16 (depends on 15) The wireless power transfer system of claim 15, wherein the first processor is configured to: record a first digital bit to a buffer in response to the monitored current crossing a threshold; and record a second digital bit to the buffer in response to the monitored current not crossing the threshold. ### Claim 17 (depends on 16) The wireless power transfer system of claim 16, wherein the threshold is associated with a trailing edge voltage spike within the inverter. ### Claim 18 (depends on 16) The wireless power transfer system of claim 16, wherein the threshold is associated with a leading edge voltage spike within the inverter. ### Claim 19 (depends on 15) The wireless power transfer system of claim 15, wherein the first processor is configured to: record a first digital bit to a buffer in response to the monitored current shifting phase; and record a second digital bit to the buffer in response to the monitored current not shifting phase. ### Claim 20 (depends on 15) The wireless power transfer system of claim 15, wherein the first processor is configured to receive and execute the executable instruction. ### Claim 21 (depends on 15) The wireless power transfer system of claim 15, wherein the load device is a portable electronic device.