Reducing corruption of communication in a wireless power transmission system
First Claim
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1. A method for reducing data corruption in a wireless power transmission system comprising:
- providing power from a power source to a transmitter;
transmitting power from a primary coil in the transmitter to a secondary coil in a receiver by induction;
rectifying a voltage induced on the secondary coil by the transmission of the power from the primary coil to the secondary coil;
transmitting data from the receiver to the transmitter via backscatter modulation by varying a load across the secondary coil;
continually measuring load current, storing a value representative of the measured load current, during the transmission of data from the receiver to the transmitter limiting a change in current through the receiver to a level within a predetermined value of the stored value of current just before a communication packet is sent utilizing a control circuit while the voltage is induced on the secondary coil, wherein the load continues to receive power during data transfer and interference with the data transfer is reduced.
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Abstract
An embodiment of the invention provides a method for reducing data corruption in a wireless power transmission system. Power is transmitted from a primary coil to a secondary coil by induction. The voltage induced on the secondary coil by induction is rectified. The change in current supplied to a load configured to be coupled to the wireless power transmission system is limited.
37 Citations
19 Claims
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1. A method for reducing data corruption in a wireless power transmission system comprising:
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providing power from a power source to a transmitter; transmitting power from a primary coil in the transmitter to a secondary coil in a receiver by induction; rectifying a voltage induced on the secondary coil by the transmission of the power from the primary coil to the secondary coil; transmitting data from the receiver to the transmitter via backscatter modulation by varying a load across the secondary coil; continually measuring load current, storing a value representative of the measured load current, during the transmission of data from the receiver to the transmitter limiting a change in current through the receiver to a level within a predetermined value of the stored value of current just before a communication packet is sent utilizing a control circuit while the voltage is induced on the secondary coil, wherein the load continues to receive power during data transfer and interference with the data transfer is reduced. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 18, 19)
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9. A wireless power transmission system comprising:
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a transmitter couplable to a source of power; a receiver having an input inductively couplable to the transmitter and an output couplable to a load; wherein the transmitter transmits power to the receiver, and the receiver receives the power from the transmitter; the receiver transmitting data to the transmitter across the inductive coupling via backscatter modulation by varying a load in the receiver; a control circuit in the receiver for controlling current flow to the load through the receiver when the load is coupled to the receiver, the control circuit, continually measuring load current, storing a value representative of the measured load current, limiting current through the receiver to a level of current within a predetermined value of the stored value just before a communications packet is sent when the receiver is transmitting data to the transmitter via backscatter modulation, wherein the load continues to receive power from the receiver during data transmission and interference with the data transmission is reduced. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. A wireless power transmission system comprising:
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a transmitter couplable to a source of power; a receiver having an input inductively couplable to the transmitter and an output couplable to a load; wherein the transmitter transmits power to the receiver, and the receiver receives the power from the transmitter; the receiver transmitting data to the transmitter across the inductive coupling via backscatter modulation by varying a load in the receiver; wherein during transmission of data from the receiver to the transmitter, a current supplied to the load is adaptively limited, wherein the receiver comprises; a rectifier circuit having an output; a switch having an input, a first output and a second output; a charge control circuit having an input and an output; wherein the output of the rectifier circuit is connected to the first output of the switch and to the input of the charge control circuit; wherein the input of the receiver is connected to the input of the switch; wherein the second output of the switch is connected to ground; wherein the output of the charge control circuit is connected to the output of the receiver, wherein the charge control circuit comprises; a current sensor having an input, a first output and a second output; a charge pump having an input and an output; a first op-amp having a first input, a second input and an output; a second op-amp having a first input, a second input and an output; an NFET having a gate, drain and source; a first diode having a cathode and an anode; a second diode having a cathode and an anode; a capacitor having a first terminal and a second terminal; a first resistor having a first terminal and a second terminal; a second resistor having a first terminal and a second terminal; a third resistor having a first terminal and a second terminal; a fourth resistor having a first terminal and a second terminal; wherein the input of the charge control circuit is connected to the input of the current sensor; wherein the first output of the current sensor is connected to the input of the charge pump, the drain of the NFET, and the cathode of the second diode; the second output of the current sensor is connected to the second input of the first op-amp, the first input of the second op-amp and the first terminal of the first resistor; wherein the first terminal of second resistor is connected to the second input of the second op-amp and the first terminal of the third resistor; wherein the output of the charge pump is connected to the gate of the NFET and the anode of the first diode; wherein the output of the first op-amp is connected to the cathode of the first diode; wherein the output of the second op-amp is connected to the second terminal of the third resistor and the first terminal of the fourth resistor; wherein the first input of the first op-amp is connected to the second terminal of the fourth resistor and the first terminal of the capacitor; wherein the output of the charge control circuit is connected to the anode of the second diode and the source of the NFET; wherein the second terminal of the first resistor, the second terminal of the second resistor and the second connection of the capacitor are connected to ground.
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17. A wireless power transmission system comprising:
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a transmitter couplable to a source of power; a receiver having an input inductively couplable to the transmitter and an output couplable to a load; wherein the transmitter transmits power to the receiver, and the receiver receives the power from the transmitter; the receiver transmitting data to the transmitter across the inductive coupling via backscatter modulation by varying a load in the receiver; wherein during transmission of data from the receiver to the transmitter, a current supplied to the load is adaptively limited, wherein the receiver comprises; a rectifier circuit having an output; a switch having an input, a first output and a second output; a charge control circuit having an input and an output; wherein the output of the rectifier circuit is connected to the first output of the switch and to the input of the charge control circuit; wherein the input of the receiver is connected to the input of the switch; wherein the second output of the switch is connected to ground; wherein the output of the charge control circuit is connected to the output of the receiver, wherein the charge control circuit comprises; a current sensor having an input, a first output and a second output; an analog-to-digital converter having an input and an output; a digital-to-analog converter having an input and an output; an op-amp having a first input, a second input and an output; an NFET having a gate, drain and source; a first resistor having a first terminal and a second terminal; a second resistor having a first terminal and a second terminal; wherein the input to the charge control circuit is connected to the input of the current sensor; wherein the first output of the current sensor is connected to the drain of the NFET; wherein the second output of the current sensor is connected to the input of the analog-to-digital converter and first terminal of the first resistor; wherein the plurality of outputs from the analog-to-digital converter are connected to the plurality of inputs in the digital-to-analog converter; wherein the output of the digital-to-analog converter is connected to the first input of the op-amp; wherein the second terminal of the first resistor is connected to the first terminal of the second resistor and to the second input of the op-amp; wherein the output from the op-amp is connected to the gate of the NFET; wherein the source of the NFET is connected to the output of the charge control circuit; wherein the second terminal of the second resistor is connected to ground.
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Specification