Patent ID: 7822383

Claim:
A wireless communication apparatus with a semiconductor integrated circuit which has a non-contact IC card function and a wireless reader/writer function for a non-contact IC card, comprising: an antenna configured to carry out communication with an external non-contact IC card and an external wireless reader/writer, said antenna including a loop of coil with plural windings; demodulation means for demodulating a first received signal transmitted from the external wireless reader/writer and received through the antenna or a second received signal transmitted from the external non-contact IC card; full-wave rectification and smoothing means for subjecting the first received signal to full-wave rectification and smoothing; first transmission means for transmitting a first transmission signal to the external wireless reader/writer through the antenna while the semiconductor integrated circuit is in an non-contact IC card mode of operation; second transmission means for transmitting a second transmission signal to the external non-contact IC card through the antenna while the semiconductor integrated circuit is in a wireless reader/writer mode of operation; and a capacitor connecting the second transmission means to a center tap of the antenna, wherein when the second transmission means drives the antenna, a current from the second transmission means flows only to a half of the windings of the loop of coil of the antenna and an another current flows through a remaining portion of the loop of coil by electromagnetic induction.