Research On New Type Multiple High Accuracy A/D Converter And Its Application

With the rapid development of very large scale integrate circuit technology and application of electronic computer in engineering field, the new design idea and manufacture technology of A/D converter appear constantly. In order to meet the needs of all kinds of test and control task, a lot of A/D convert circuit which has different structure and performance comes forth. In the aspect of multiple high accuracy A/D converter, a new type twice sampling A/D converter with digital feedback is talent showing itself.This paper introduced the principle of digital feedback twice sampling A/D converter in detail, and analyzed its error deeply. In the aspect of hardware circuit design, put forward many methods and make primary circuit more perfect. Especially in the part of logic control, adopt the newest digital system programmable logic device, simplify system design, reduce system scale and improve system reliability. In the aspect of software design, optimize arithmetic and make data disposal suitable.Digital feedback twice sampling A/D converter is based on common accurate dual integral A/D converter. During the second sampling, through the control logic, programmable counters and switch control, realize digital feedback and substitute primary analogue feedback realized by high accuracy D/A converter. Compared with primary second sampling A/D converter, it realizes digital feedback by digital circuit and doesn't adopt high accuracy D/A converter with complex technology and high price. It has many excellent qualities, such as high-integration, high-accuracy, widely used, low-price. It can be widely used in test and measure system, scientific instrument, iatric instrument, automatic test system etc. So popularizing this new type A/D converter has very significant meaning.