Abstract: According to the poor anti-interference existed in the intrinsic safe sensor and the weak loading ability problem of the intrinsic safe power, the paper prov ided the power circuit design and the realization plan of the AD2441 intrinsic safe sensor based on current mode controlled synchro BUCK chip.The paper introduced th e anti-interference design of the power circuit, intrinsic safe treatment, current limit start-up circuit design, hardware design of the power circuit as well as the selection and optimization of the key parts.According to the available parameters of the power circuit, a table-look-up judgment was conducted on the intrinsic safe performances of the circuit. Relevant measurement and tests were conducted on the anti-interference performances and loading ability performances of the power circuit.The measuri ng and test results showed that the power circuit could have the features of good anti-interference, high efficiency and small ripple and the intrinsic safe performances C ould fully meet the requirements of GB 3836.4- -2010.