| 摘要 |
PURPOSE:To permit manufacturing of A-D converters with superior temperature characteristics by a construction wherein a voltage dividing circuit connected with a power supply for driving a load cell is coupled to the A-D converter via a voltage follower circuit. CONSTITUTION:A load cell is driven by a first DC power supply to operate an amplification circuit thereof, and output from the amplification circuit is processed by an A-D converter which is driven by a second DC power supply. Output from a voltage dividing circuit with respect to the first power supply is supplied via a voltage follower circuit as reference voltage for the A-D converter. For example, a load cell 31, operational amplifiers 42, 43, 44 and a zero point adjustment circuit 71 are driven by a first DC power supply (across A B; +15V, across B C; -5V), while an A-D converter 100 is driven by a second DC power supply (across D E; +5V). Then, voltage from a reference voltage generating circuit comprising a voltage dividing circuit 85 connected to across AB and a voltage follower circuit 86 is supplied to the A-D converter as reference voltage. |
