| 摘要 |
<P>PROBLEM TO BE SOLVED: To drastically improve the reliability of NFC communications by optimally controlling a received signal according to a communication mode. <P>SOLUTION: In an NFC chip, a received-signal-amplitude control circuit 14 for setting an amplitude of an input received signal is provided. The received-signal-amplitude control circuit 14 is constituted from shunt circuits 30 to 32, attenuation circuits 33 to 35, and a termination resistor unit 36. The shunt circuits 30 to 32 non-linearly attenuate a received signal amplitude based on a shunt-off signal shnt_off output in a card mode of the NFC chip. In addition, the attenuation circuits 33 to 35 linearly attenuate the received signal amplitude based on an attenuate-off signal att_off output from an MPU in the card mode of the NFC chip. <P>COPYRIGHT: (C)2012,JPO&INPIT |
