The power supply is a dynamical of every kind of electronics, electricity equipments work,and it is an indispensability part of automatization. it is extensive to apply to study of science, economic developments, national defense facilities and people life and so on, It is the base of electronic equipments and electromotors. In numerous types of the power supply, the direct current voltage-stabilized source application most for extensive, it is vitally related with the national economy each section, in the laboratory, IT industry, mine for minerals, abbreviated wiring wait realm especially more widespread. The circuit has four parts: regulated voltage supply, regulated current supply, DC-DCconverter and display. The voltage supply uses two-stage control. The first is a DC-DC switching power and the second is a linear circuit. The constant voltage drop technology is adopted between the two stages to obtain high efficiency. The current supply is the classical feedback series circuit and make some improvements .The DC-DC converter is a isolated feed back switching power with high efficiency ,wide range output of voltage and current。The display is AD7107.
Key words：regulated voltage supply regulated current supply DC-DC converter display
