| 摘要 |
PROBLEM TO BE SOLVED: To provide a differential communication transmitter which normally transmits transmission data without using a common mode choke coil if common mode noise over a power source voltage range is generated. SOLUTION: A source follower circuit composed of FETs Q1 to Q4 is arranged between communication lines L1 and L2 and a power source line and between the communication lines L1 and L2 and a ground line. In addition, voltage sources 11 to 14 which generate target potential V1 and V2 higher than potential between the communication lines L1 and L2 by a specified voltage and target potentials V3 and V4 lower than the potential between the communication lines L1 and L2 by a specified voltage are arranged for the communication lines L1 and L2. When transmission data are a value 1 (High), the target potential V1 and V4 are inputted into gates Q1 and Q4 through operation switches 21 and 24, and when transmission data are a value 0 (Low), the target potential V2 and V3 are inputted into gates Q2 and Q3 through operation switches 22 and 23. Thereby, a potential difference between the communication lines L1 and L2 is controlled to be a constant voltage corresponding to transmission data. COPYRIGHT: (C)2011,JPO&INPIT
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