FOREIGN OBJECT DETECTING DEVICE, WIRELESS POWER TRANSMITTING DEVICE, AND WIRELESS POWER TRANSMISSION SYSTEM

摘要

An object detecting device includes a coil array including coils, short-circuit switches connected in parallel with the coils, an oscillator circuit that outputs, to the coils, a voltage including an alternating current component, selection switches connected between the coils and the oscillator circuit, a detecting circuit that detects an object based on a change in a physical value such as voltage, and a control circuit that opens and closes the short-circuit switches and the selection switches. When a first selection switch is closed, a first short-circuit switch, which is connected to the first selection switch, is opened. The other selection switches are opened, and the other short-circuit switches are closed.

主权项

1. A foreign object detecting device comprising:
a coil array that includes coils; short-circuit switches, each of which is connected in parallel with each of the coils and each of which establishes or breaks an electrical connection between both ends of the coil; selection switches, each of which establishes or breaks an electrical connection between each of the coils and an oscillator circuit; a detecting circuit that detects an amount of change, from a predetermined reference value, in a physical value that changes in accordance with a change in impedance of each of the coils; and a control circuit that opens and closes each of the short-circuit switches and each of the selection switches, wherein the control circuit establishes an electrical connection between a first coil included in the coils and the oscillator circuit by closing a first selection switch included in the selection switches and opens a first short-circuit switch included in the short-circuit switches connected in parallel with the first coil, wherein the control circuit breaks an electrical connection between a second coil included in the coils and the oscillator circuit by opening a second selection switch included in the selection switches and closes a second short-circuit switch included in the short-circuit switches connected in parallel with the second coil, and wherein the detecting circuit detects the amount of change, from the predetermined reference value, in the physical value that changes in accordance with the change in the impedance of the first coil, which is electrically connected to the oscillator circuit and determines whether there is a foreign object based on the amount of change.