In-Band Signaling Within Wireless Power Transfer Systems

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.

1 . (canceled) 
     
     
         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.   
     
     
         3 . 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.   
     
     
         4 . The method of  claim 3 , wherein delaying the turn off of the switch comprises delaying a turn off until current through the switch reverses. 
     
     
         5 . 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. 
     
     
         6 . 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.   
     
     
         7 . The method of  claim 2 , wherein the update comprises an indication that a battery within the load device is charged. 
     
     
         8 . The method of  claim 2 , wherein the update comprises authentication information. 
     
     
         9 . The method of  claim 2 , wherein the update comprises executable instructions received by a processor of the source device. 
     
     
         10 . The method of  claim 2 , wherein the update comprises temperature information corresponding to a temperature of the load device. 
     
     
         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.   
     
     
         12 . 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.   
     
     
         13 . The method of  claim 11 , wherein the update comprises a temperature of the load device. 
     
     
         14 . The method of  claim 11 , wherein the update comprises executable instructions for a processor of the source device. 
     
     
         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. 
 
 
   
     
     
         16 . 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.   
     
     
         17 . The wireless power transfer system of  claim 16 , wherein the threshold is associated with a trailing edge voltage spike within the inverter. 
     
     
         18 . The wireless power transfer system of  claim 16 , wherein the threshold is associated with a leading edge voltage spike within the inverter. 
     
     
         19 . 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.   
     
     
         20 . The wireless power transfer system of  claim 15 , wherein the first processor is configured to receive and execute the executable instruction. 
     
     
         21 . The wireless power transfer system of  claim 15 , wherein the load device is a portable electronic device.