| 摘要 |
PROBLEM TO BE SOLVED: To achieve simple, highly accurate and reliable A-D conversion processing at a low cost in an A-D conversion system of a bipolar analog input signal by using a single control power source and a unipolar A-D converter. SOLUTION: A reference power supply of an analog signal having positive and negative polarities divides a single supply voltage Vdd at a partial pressure circuit of resistances R1, R2, and generates a virtual ground (VG) voltage by making the partial pressure voltage pass in a voltage follower circuit VF. The voltage follower circuit monitors an A-D converter 4 with its output as an analog input, compensate an input amount of the analog signal, and achieves a duplex configuration. Further, the voltage follower circuit doubles an analog filter 2, a multiplexer 3 and the A-D converter 4. COPYRIGHT: (C)2008,JPO&INPIT
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