| 摘要 |
<P>PROBLEM TO BE SOLVED: To efficiently control feeding power in wireless power feeding of a magnetic field resonance type. <P>SOLUTION: A wireless power-feeding device 116 wirelessly feeds power from a power-feeding coil L2 to a power-receiving coil L3 based on a magnetic-field resonance phenomenon between the power-feeding coil L2 and the power-receiving coil L3. A power transmission control circuit 200 supplies AC power to the power-feeding coil L2 at a driving frequency fo, thereby feeding the AC power from the power-feeding coil L2 to the power-receiving coil L3. A phase detection circuit 150 detects a phase difference between a voltage phase and a current phase of the AC power. Specifically, the phase detection circuit 150 compares a first detection period in which a signal T2 is high level and a second detection period in which a signal S2 is high level, and then detects the phase difference by detecting the length of the period in which the first detection period and the second detection period are overlapped. <P>COPYRIGHT: (C)2012,JPO&INPIT |
