| 摘要 |
PROBLEM TO BE SOLVED: To detect, without newly providing a sensor, foreign matter present near a detection coil, that its, a magnetic coupling element, and improve detection accuracy.SOLUTION: A foreign matter detection circuit comprises detection parts 32, 33 that measure or calculate an effective resistance value for one or more magnetic coupling elements L3 composed of one or more coils, or an elective resistance value for a circuit including at least the magnetic coupling element L3, and determine the presence or absence of foreign matter from a change in the effective resistance value. The detection parts 32, 33 make the above-described determination after a threshold used for determination of the presence or absence of a foreign matter is determined from the effective resistance value obtained when a device having a magnetic coupling element to be magnetically coupled with the magnetic coupling element L3 is disposed in the position where the device is to be magnetically coupled with the magnetic coupling element L3 and there are not any foreign matter around it.SELECTED DRAWING: Figure 3 |
