ELECTRIC POWER TRANSMITTING DEVICE, ELECTRIC POWER RECEIVING DEVICE, AND POWER SUPPLY METHOD USING ELECTRIC POWER TRANSMITTING AND RECEIVING DEVICES

• US 20150318714A1
• Filed: 07/13/2015
• Published: 11/05/2015
• Est. Priority Date: 06/17/2010
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KAMATA, Koichiro
• Application Number:
  US14/797,833
• Publication Number:
  US 20150318714A1
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/00 Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
• CPC Class Codes: H02J 7/00034 Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
• CPC Class Codes: H04B 5/266 One coil at each side, e.g. with primary and secondary coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

In electric power supply through wireless signals, electric power is supplied efficiently, even when distance fluctuation is caused between an electric power transmitting device and an electric power receiving device. Even when distance fluctuation is caused between the electric power transmitting device for supplying electric power with the use of wireless signals and the electric power receiving device for receiving electric power supplied from the electric power transmitting device, the Q value of the electric power transmitting device is adjusted to optimize the transmission efficiency. The impedance of a resonance circuit of the electric power transmitting device is fluctuated at a constant frequency, the resulting reflected wave is detected as a response signal by the electric power transmitting device, and the Q value of the electric power transmitting device is adjusted to optimize the transmission efficiency.

Claims

1. An electric power transmitting device comprising:

an electric power radiation circuit comprising an antenna and a variable resistive element; and

a modulated signal detection circuit configured to change a resistance value of the variable resistive element in order to change a Q value of the electric power radiation circuit.

2. The electric power transmitting device according to claim 1, further comprising a power source for supplying high-frequency power to the electric power radiation circuit.

3. The electric power transmitting device according to claim 1, wherein the antenna comprises a coiled antenna.

4. An electric power receiving device comprising:

a resonance circuit, a modulation circuit including a transistor, and a logic circuit,

wherein the logic circuit is connected to a gate of the transistor included in the modulation circuit, and

wherein a switching operation for the transistor is configured to change an impedance of the resonance circuit.

5. The electric power receiving device according to claim 4, wherein the resonance circuit comprises a coiled antenna.

6. The electric power receiving device according to claim 4, wherein the transistor comprises an oxide semiconductor layer in which a channel formation region is formed.