CONTACTLESS DATA CARRIER READ/WRITE UNIT, ANTENNA OUTPUT CIRCUIT, AND ANTENNA CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a contactless data carrier read/write unit, an antenna output circuit and an antenna circuit, having good power efficiency with small size at low cost.

SOLUTION: The contactless data carrier read/write unit includes a pulse amplifier 3 for outputting a first power amplification signal based on a phase 0 [rad] square-wave pulse signal B having an identical frequency to a carrier wave signal A; a pulse amplifier 4 for outputting a second power amplification signal based on a phase π [rad] square-wave pulse signal C; a modulation circuit 7 for supplying a voltage having a modulated power voltage based on a transmission data to the pulse amplifiers 3 and 4; an antenna output circuit 11 having a low pass filter 5 for attenuating harmonic wave components of the first and second power amplification signals; a matching circuit 8 having three capacitors of symmetric configuration to first and second input signals output from the low pass filter 5; and an antenna circuit 12 having an antenna coil 9 for synthesizing the first and the second input signals, so as to transmit the result to a contactless IC card 10.

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