| 摘要 |
PURPOSE:To improve the analog-digital converting accuracy by providing a reference voltage compensating circuit on the same IC on which a parallel type analog-digital converter is mounted. CONSTITUTION:A current from a current source is adjusted by a voltage difference between a midpoint 13 having the largest error of the reference voltage and a terminal 14 to which a voltage of the ideal value of the reference voltage is applied, and the adjusted current is applied to connecting points 15, 13 and 16 of the 64th, 128th and 129th comparators at three series resistors. The voltage difference between a voltage at a midpoint 128 and the voltage at the terminal 124 is fed back by a differential amplifier 17, a current source comprising pnp transistors (TRs) 25, 26, 27 and resistors 28, 29, 30, a differential amplifier 24, and a current source comprising npn TRs 25, 26, 27 and resistors 28, 29, 30, the current value of the current sources is decided so that the potential at a connecting point 13 and the terminal 14 is equal to each other, the potential at the terminals 13, 15, 16 is compensated and the linearity is improved. |
