It is necessary to isolate the high and low potentials between the control system and the main circuit under the high voltage and strong magnetic field. It is important to ensure that the driving signal sent to the control board is reduced to a no-output state when a fault occurs. High and low potential isolation can be achieved in switching power supplies with isolated drivers. At the same time, the control signal and protection circuit are interlocked to ensure that it can send an invalid signal to the switching device. In this paper, the control signal is converted from electrical to optical and transmitted through fiber optics to an opto-electrical receiving device, where the optical signal is converted to an electrical signal. The control signal can be amplified by the driving circuit board. The switch device can be driven by the driving circuit board. The high and low potential isolation between the control system and the main circuit can be resolved by the driving board. An interlock circuit is established to ensure that the driving circuit board does not receive the valid control signal. The negative voltage signal can be got, and the power electronic device is reliably shut down and the power electronic device can be protected. This paper discusses the working principle of this scheme, the system composition, design analysis of hardware circuits, and related calculations to determine circuit parameters. Experimental results show that the switching power supply control mode based on this structure has a simple circuit structure, high and low potential isolation voltage up to 10 kV. The switching power supply is not affected by external electromagnetic interference, and the driving signal has good stability.