A kind of current coupled power supply device with positive and negative output is proposed for the need of power supply for multiple types of on line monitoring device.The method of theoretical deviation with combination of simulation is adopted to study the influence of magnetic without and without air gap on the operation condition of power supply.The variation curve secondary voltage of power supply coil with primary current and the output power with primary current and load resistance is obtained by the test so to provide the base for the power design.In view of such situation that high secondary output voltage needs electrical isolation of power supply coil and general positive and negative output integrated chips cannot meet requirement

it is proposed to adopt

active clamp ZVS-PWM forward converter as electrical isolation and voltage reduction circuit to achieve positive and negative output power supply.Power conversion efficiency is improved by the ZVS-PWM soft switching technology and synchronous rectification technology and the simulation analysis and verification are performed.The power supply with output voltage±12 V DC and output power output 1.44 W is designed and made

and ideal test result is obtained.