Circuit for multistage A=D converter - has differential amplifier stage of two amplifiers with interconnected negative outputs, coupled to voltage divider

摘要

The converter has a coarse and fine conversion stage for the analog input signal, which is compared with threshold wave voltages, periodically and sequentially scanned and tapped as a digital output signal at the respective output. The comparison is carried out by a differential amplifier stage of two amplifiers with identical absolute amplifying ratio and two symmetric outputs. The two negative outputs of these amplifiers are interconnected and coupled both to the voltage divider of the fine conversion stage and to positive output of the first amplifier via a load resistor. This positive output is connected to all negative and positive inputs of the comparative amplifiers of the fine conversion stage. The positive output of the second differential amplifier is connected both to upper drain terminal of the voltage divider and to the remaining input of the upper comparative amplifier. The inverting input of the first amplifier is coupled both to the inverting input of the second amplifier and to the analog outputs of a converter stage.