US-12620834-B2 - Wireless charging with split resonant capacitors

Abstract

An example device includes a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and one or both of: a driver circuit configured to drive the plurality of capacitor and wireless charging coil series pairs with a first common signal; or a sink circuit configured to receive a second common signal from the plurality of capacitor and wireless charging coil series pairs.

Inventors

• Li Wang
• Liang Jia
• Liyu Yang
• Stefano Saggini

Assignees

• GOOGLE LLC

Dates

Publication Date

20260505

Application Date

20210810

Claims (9)

1. 1 . A wireless charging sink device comprising: a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and a sink circuit configured to receive a second common signal from the plurality of capacitor and wireless charging coil series pairs.
2. 2 . The wireless charging sink device of claim 1 , wherein each of the wireless charging coils comprises a respective bundle of wires.
3. 3 . The wireless charging sink device of claim 2 , wherein each of the respective bundles of wires comprises one of: a respective Litz wire; or a respective trace wire.
4. 4 . The wireless charging sink device of claim 1 , wherein a respective amount of current flowing through each of the plurality of capacitor and wireless charging coil series pairs is approximately equal.
5. 5 . The wireless charging sink device of claim 1 , wherein wireless charging coils of the plurality of capacitor and wireless charging coil series pairs are located on a discrete coil component.
6. 6 . The wireless charging sink device of claim 5 , wherein capacitors of the plurality of capacitor and wireless charging coil series pairs are located on the discrete coil component.
7. 7 . The wireless charging sink device of claim 5 , wherein capacitors of the plurality of capacitor and wireless charging coil series pairs are located on a board that is different than the discrete coil component.
8. 8 . The wireless charging sink device of claim 1 , wherein the sink circuit comprises a rectifier.
9. 9 . A system comprising: a wireless charging source device; and a wireless charging sink device, wherein the wireless charging source device is configured to wirelessly charge the wireless charging sink device, and wherein the wireless charging sink device comprises: a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and a sink circuit configured to receive a common signal from the plurality of capacitor and wireless charging coil series pairs.

Description

BACKGROUND Computing devices, such as smartphones, laptops, wearable devices, and tablets, may include wireless charging capabilities. Computing devices may operate as wireless charging source devices that wirelessly provide power or wireless charging sink devices that wirelessly receive power. For instance, a wireless charging sink device may include a receiver coil and other components capable of transducing a magnetic field into an electrical power signal that may be used to charge a battery of the computing device or otherwise operate components of the computing device. Similarly, a wireless charging source device may include a power supply that output a signal to a transmitter coil that causes the transmitter coil to generate a magnetic field. A controller of the wireless charging source device may adjust operation of the power supply to control an amount of power provided and/or properties of the electrical power signal at the wireless charging receive device. SUMMARY This disclosure generally relates to wireless charging devices that include split resonant capacitors. A wireless charging device may include a resonant tank that includes one or more resonant capacitors and one or more coils that transduce energy between magnetic fields and alternating current (AC) power signals. In some examples, the resonant capacitors may all be electrically in parallel and the coils may all be in parallel, with the parallel capacitors being in series with the parallel coils (i.e., such that all current flows through a single node between the capacitors and the coils). However, such an arrangement may yield various disadvantages. For instance, eddy current losses may be a large loss contributor in wireless charging systems. In accordance with one or more aspects of this disclosure, a wireless charging device may include a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel. For instance, the collection of capacitor and wireless charging coil series pairs may all share a common input node and a common output node. By including the plurality of capacitor and wireless charging coil series pairs, eddy current losses may be reduced. In this way, wireless charging efficiency may be improved. As one example, a device includes a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and a driver circuit configured to drive the plurality of capacitor and wireless charging coil series pairs with a common signal. As another example, a system includes a wireless charging source device; and a wireless charging sink device, wherein the wireless charging source device is configured to wirelessly charge the wireless charging sink device, and wherein the wireless charging source device comprises: a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and a driver circuit configured to drive the plurality of capacitor and wireless charging coil series pairs with a common signal. As another example, a system includes a wireless charging source device; and a wireless charging sink device, wherein the wireless charging source device is configured to wirelessly charge the wireless charging sink device, and wherein the wireless charging sink device comprises: a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel; and a driver circuit configured to drive the plurality of capacitor and wireless charging coil series pairs with a common signal. The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a block diagram illustrating a system that includes a wireless charging source device and a wireless charging sink device, at least one of which includes a plurality of capacitor and wireless charging coil series pairs that are collectively in parallel, in accordance with one or more aspects of this disclosure. FIG. 2 is a schematic diagram illustrating a system that includes a wireless charging source device and a wireless charging sink device, at least one of which includes a split resonant capacitor configuration, in accordance with one or more aspects of this disclosure. FIG. 3 is a conceptual diagram illustrating an example of a plurality of wireless charging coils, in accordance with one or more techniques of this disclosure. FIG. 4 is a conceptual diagram illustrating a cross-section of a portion of wires of a plurality of wireless charging coils, in accordance with one or more aspects of this disclosure. FIGS. 5A and 5B are graphs depicting currents flowing through wireless charging coils at various frequencies, in accordance with one or more aspects of this disclosure. FIGS. 6A and 6B are graphs depicting currents flowing through wireless charging coils, in accordan