Development Of Multi-slope High Precision A/D Converter

Analog-to-digital converters (ADCs) are used for converting analog signals to digital ones and with the rapid applicator of electronic computer in engineering field, they find wide application in many fields.This paper, introduces a compound multi-slope A/D converter is implemented by the combination of the charge balance and single slope A/D converter to meet the need of high precision voltage measurement based on common dual integral technology. While integrating the input voltage, the high bit readings are acquired during the charger balance process, and the low readings are achieved during the single slope phase. In the part of logic control, adopt the newest digital system programmable logic device—FPGA with representative Nios Embedded System of soft IP core introduced by Altera Corporation. Nios has the characteristic of reconfiguration, which brings more flexibility to the designer. It is also said that Nios has offered a kind of brand-new train of thought to Embedded System designer. This paper illustrates how to use Nios CPU to design Embedded System including counter, display with LED, watch dog configuration, communication interface, Ethernet controller interface, etc and the detailed process by the implement of IP cores provided by both manufacturer and user-defined and introduce a applicable method to calibrate readings in the end. In the aspect of hardware circuit design, this paper puts forward many methods and makes primary circuit more perfect.