Patent attributes
An electronic circuit capable of carrying out communications by inductive coupling with minimum power consumption between substrates. Although the amplification factor of the amplifier 10a is 1, the amplification factors of the amplifiers 10b through 10d are, respectively, 2, 4 and 8. Amplification is carried out at the amplification factors 1 through 15 (=1+2+4+8) as a whole by a combination thereof. The transmit power control register 21 outputs ON and OFF signals to the respective amplifiers 10a through 10d so as to bring about transmit power responsive to the distance to a substrate having a receiver coil which is a destination of transmission (that is, the distance between a transmitter coil and a receiver coil), in further detail, so as to have an amplification factor by which transmit power proportionate to the distance can be obtained, and selects a combination of the amplifiers 10b through 10d.
