| 摘要 |
A load modulation communication circuit connected to a secondary coil arranged facing a primary coil, comprises: a center tap connected to the secondary coil; a switch unit connected at its one end to the center tap via a resistor and at the other end to approximately ground; and a control circuit which is connected to the switch unit to control an on/off action of the switch unit and also connected to both ends of the secondary coil or one end of the secondary coil and the center tap to control communications through the secondary coil by controlling the on/off action of the switch unit; wherein when the switch unit is off, the secondary coil obtains electric power and receives the information from the primary coil, while when the switch unit is on, the center tap is connected to approximately ground via the resistor and thus a load on the secondary coil is increased, thereby causing the secondary coil to transmit information to the primary coil.
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