| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To solve a problem wherein a noise is generated by an operation of a protection circuit to cause an unstable operation, as the protection circuit is provided in some cases not to generate excessive electric power in an inside, when a radio tag exists in an environment receiving excessive electric power, in the radio tag for which a radio communication system having a reader/writer carrier wave of great electric power is estimated to be constructed. <P>SOLUTION: The radio tag has a circuit for receiving an AC signal from an outside, and for detecting an envelope, a detection circuit for detecting a level of electric power supplied from the outside, and for outputting a potential corresponding to the detected electric power, the protection circuit for changing an impedance of a circuit receiving the electric power, in response to the electric power output from the detection circuit, and a selection circuit part for selecting the propriety of inputting the potential controlled by an input of the envelope and output from the detection circuit, into the protection circuit. <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
