US 11,990,771 B2
Detection apparatus, electric power receiving apparatus, electric power transmission apparatus, wireless electric power transmission system, and detection method
Hiroaki Nakano, Tokyo (JP); Takaaki Hashiguchi, Tokyo (JP); Shinichi Fukuda, Kanagawa (JP); and Kenichi Fujimaki, Kanagawa (JP)
Filed by Sony Corporation, Tokyo (JP)
Filed on Apr. 14, 2017, as Appl. No. 15/487,834.
Application 15/487,834 is a continuation of application No. 15/068,049, filed on Mar. 11, 2016, granted, now 9,660,699.
Application 15/068,049 is a continuation of application No. 13/551,861, filed on Jul. 18, 2012, granted, now 9,467,205, issued on Oct. 11, 2016.
Claims priority of application No. 2011-162589 (JP), filed on Jul. 25, 2011.
Prior Publication US 2017/0222489 A1, Aug. 3, 2017
Int. Cl. H02J 50/80 (2016.01); H02J 50/12 (2016.01); H02J 50/60 (2016.01); H04B 5/79 (2024.01); H02J 7/00 (2006.01); H02J 7/34 (2006.01)
CPC H02J 50/80 (2016.02) [H02J 50/12 (2016.02); H02J 50/60 (2016.02); H04B 5/79 (2024.01); H02J 7/00 (2013.01); H02J 7/345 (2013.01)] 19 Claims
OG exemplary drawing
 
1. A power reception device comprising:
a resonance circuit including a power receiving coil and a capacitor;
switching circuitry connected in series with the resonance circuit; and
control circuitry configured to generate a control signal causing the switching circuitry to switch between a conductive state and a non-conductive state based on a comparison between a measurement value and a threshold value, wherein
the switching circuitry is in the non-conductive state in a detection period of a metal foreign matter, and in a state of stopping an electric power transmission from a power transmission device,
the switching circuitry is in the conductive state in a period of the electric power transmission,
the measurement value corresponds to a value of an electrical characteristic in a state corresponding to the detection period,
the threshold value corresponds to the value of the electrical characteristic in a state in which neither the metal foreign matter nor the power reception device is present in a vicinity of the power transmission device,
the threshold value is stored in the power transmission device, and
the electrical characteristic corresponds to a ratio of voltages,
wherein the control circuitry is further configured to generate a second control signal causing the switching circuitry to switch between the conductive state and the non-conductive state based on a comparison between a second measurement value and a second threshold value, wherein the second measurement value corresponds to a value of a second electrical characteristic in a state corresponding to the detection period, and wherein the second electrical characteristic corresponds to an impedance.