Method and apparatus for wirelessly charging portable electronic devices
First Claim
Patent Images
1. 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 shunt 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 shunt 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 shunt 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; and
wherein;
the comparison circuitry is configured to sample the voltage across the output of the switching transistor just before the transistor turns back on during the switching cycle, wherein the comparison circuitry is synchronized to the switching frequency of the switching transistor but samples at a lower rate.
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.
60 Citations
15 Claims
-
1. 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 shunt 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 shunt 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 shunt 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; and wherein; the comparison circuitry is configured to sample the voltage across the output of the switching transistor just before the transistor turns back on during the switching cycle, wherein the comparison circuitry is synchronized to the switching frequency of the switching transistor but samples at a lower rate. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
-
Specification