Method and Apparatus for Wirelessly Charging Portable Electronic Devices
First Claim
Patent Images
1. An electronic device comprising:
- a power amplifier circuit for use in wirelessly charging an external portable device, the power amplifier having a switching transistor and a resonant circuit, the resonant circuit having at least one variable capacitance and at least one variable inductance, the variable inductance being positioned for magnetic coupling to an inductance within the external portable device, the external portable device creating a time varying load within the electronic device during charging operations; and
a load variation detection and compensation circuit to identify load variation within the power amplifier circuit based on feedback from the power amplifier circuit and to generate control signals to adjust the at least one variable capacitance and the at least one variable inductance of the resonant circuit to compensate for variations in load, wherein the load variation detection and compensation circuit operates continually during charging operations to compensate for time varying load.
1 Assignment
0 Petitions
Accused Products
Abstract
Wireless charging of portable electronic devices is carried out by detecting load variations caused by the device and dynamically compensating for these variations during charging to increase system efficiency and regulate delivered power. In some embodiments, load variations are tracked by comparing a feedback signal to a value range and determining whether the feedback value is higher than, lower than, or within the range of values. This information is then used to modify one or more parameters associated with a power amplifier in a transmitter device.
-
Citations
21 Claims
-
1. An electronic device comprising:
-
a power amplifier circuit for use in wirelessly charging an external portable device, the power amplifier having a switching transistor and a resonant circuit, the resonant circuit having at least one variable capacitance and at least one variable inductance, the variable inductance being positioned for magnetic coupling to an inductance within the external portable device, the external portable device creating a time varying load within the electronic device during charging operations; and a load variation detection and compensation circuit to identify load variation within the power amplifier circuit based on feedback from the power amplifier circuit and to generate control signals to adjust the at least one variable capacitance and the at least one variable inductance of the resonant circuit to compensate for variations in load, wherein the load variation detection and compensation circuit operates continually during charging operations to compensate for time varying load. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A machine implemented method for wirelessly charging a portable electronic device, the method comprising:
-
applying an input signal to a switched power amplifier to generate a time varying current within a variable inductance of a resonant circuit of the switched power amplifier, the variable inductance being magnetically coupled to a coil within the portable electronic device to be charged; determining whether a feedback voltage from the switched power amplifier is above, below, or within a predetermined voltage range; and modifying the variable inductance and a variable capacitance of the resonant circuit of the power amplifier if the feedback voltage is above or below the predetermined voltage range to compensate for load variation and leaving the variable inductance and the variable capacitance in their present settings if the feedback voltage is within the predetermined voltage range. - View Dependent Claims (9, 10)
-
-
11. A portable electronic device that is capable of wirelessly charging other portable electronic devices, the portable electronic device comprising:
-
a battery terminal for connection to a battery; power amplifier circuitry, coupled to the battery terminal, for use in wirelessly charging an external portable device, the power amplifier circuitry having a switching transistor and a resonant circuit, the resonant circuit having at least one variable capacitance and at least one variable inductance, the variable inductance for magnetic coupling to an inductance within the external portable device, wherein the external portable device can create a time varying load within the power amplifier circuitry during charging operations; comparison circuitry to compare feedback from the power amplifier circuitry to one or more reference voltages to identify load variations in the power amplifier circuitry; and compensation circuitry to generate control signals for the at least one variable capacitance and the at least one variable inductance of the power amplifier circuitry based at least in part on the comparison result, to adjust the at least one variable capacitance and the at least one variable inductance in a manner that maintains approximately zero switch turn-on voltage for the switching transistor to achieve enhanced efficiency and to regulate the power delivered to the external portable device. - View Dependent Claims (12, 13, 14, 15, 16)
-
-
17. A portable electronic device that is capable of charging other portable electronic devices, the portable electronic device comprising:
-
a battery terminal for connection to a battery; a class-E power amplifier coupled to the battery terminal, the class-E power amplifier having a switching transistor and a resonant circuit, the resonant circuit having at least one variable capacitance and at least one variable inductance, the at least one variable inductance for magnetic coupling to a coil within an external portable device to be charged, wherein the at least one variable inductance in the first portable electronic device and the coil in the external portable device form a transformer between the devices during a charging operation, wherein a load of the external portable device is reflected into the portable electronic device through the transformer; comparison circuitry to determine whether a voltage across an output of the switching transistor is above, below, or within a predetermined voltage range at a particular point within a switching cycle of the switching transistor of the class-E power amplifier; and compensation circuitry to adjust the at least one variable capacitance and the at least one variable inductance if the comparison circuitry determines that the voltage across the output of the switching transistor is above or below the predetermined voltage range, wherein the compensation circuitry is configured to perform no adjustment to the at least one variable capacitance and the least one variable inductance if the comparison circuitry determines that the voltage across the output of the switching transistor is within the predetermined voltage range. - View Dependent Claims (18, 19, 20, 21)
-
Specification