| 摘要 |
PURPOSE:To perform high-speed conversion through simple constitution by providing integrators which sample analog input signals and perform inverse integration in parallel, and performing sampling and inverse integration selectively and simultaneously. CONSTITUTION:The integrator composed of a capacitor C1 and an operational amplifier 2 and the integrator composed of a capacitor C21 and an operational amplifier 22 which sample an input analog signal through constant current sources 7 and 9 respectively are connected in parallel. A changeover switch SW28 is controlled by a signal from a control circuit 13; while the amplifier 2 samples and integrally accumulates an input voltage in the capacitor C1, the amplifier 22 performs inverse integration through the current sources 7 and 9, and its output is integrated inversely until comparators 27 and 26 obtain the potentials of a DC power source 11 and an earth power source. When the inverse integral value attains to the earth potential, the switch 28 is changed over to allow the amplifiers 22 and 2 to perform sampling operation and inverse integration respectively, and inverse integration is performed until comparators 12 and 10 obtain the potential of the power source 11 and the earth potential. The outputs of the comparators are inputted to counters 14 and 15 through SWs 29 and 30 interlocked with the SW28 and the circuit 13, thereby outputting digital signals from the counters. |
