| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a semiconductor device of which forming electromagnetic coupling with an external device allows supply of electric power and delivery of information to/from the external device, and of which rising of temperature inside the device which is caused by supply of excessive power from the external device can be suppressed with a simple circuit configuration. <P>SOLUTION: In a semiconductor device (IC card) 3, a resonance circuit is constituted with a capacitive element 13 that has such characteristics as a capacitance value changes according to changes of ambient temperature and a power receiving antenna coil 11. The capacitive element 13 is installed near a constant voltage circuit 14 whose heating is relatively high. If the electric power supplied by electromagnetic coupling caused between the power receiving antenna coil 11 and a power transmitting antenna coil 6 provided to the external device (reader writer) 2 becomes excessive, an internal temperature rises especially due to heating inside the constant voltage circuit 14, which changes a capacitance value of the capacitive element 13, resulting in changes in resonance frequency of the resonance circuit. <P>COPYRIGHT: (C)2008,JPO&INPIT |
