| 摘要 |
PURPOSE:To eliminate the error due to the characteristics of comparator and to increase the accuracy, by applying great input voltage to the comparator before the start of operation at the final section of A/D converter selecting the slope of ramp voltage. CONSTITUTION:To the one input of the comparator 3 having the circuit constitution performing A/D conversion by selecting the slope of ramp voltage, analog signal voltage Ei and reference voltage Ev are fed by selecting them with the switches S4, S5. Thus, before the start of operation of the third section being the final section, when the switch S4 is OFF and S5 is ON with the instruction of the control circuit 4, the voltage Ev is fed to the input of the comparator 3, and the output is a given saturation EOL independently of the signal level. After that, with the instruction with the circuit 4 the switches S3, S4 are ON and S5 is OFF, the time lags tau1 , tau2 at the third section are always equal. Accordingly, since the operation is made at the circuit 4, the error caused by the operation of the comparator 3 at the part where the input difference is small, can effectively be rejected. |
