Abstract: In view of problems that power supply voltage level and power type between mine-used sensors and DC power supply system is inconsistent, a design scheme of new type of wide range DC input and intrinsic safety type power module was put forward. The power module is based on Buck and isolated flyback topology, front-end uses the Buck circuit to avoid risk caused by direct use of the flyback topology which may bring high pressure to switch tube, and the back-end uses isolated flyback topology to meet isolation requirements of electrical equipment with non-intrinsic safety and intrinsic safety. The power module has advantages of anti reverse input, DC9-350 V input, intrinsic safety power output and easy integration.