Introduction. Electric vehicle voltage converters are used to provide power to low-voltage consumers of electricity (warning lights, lamps, pumps, etc.). The importance of charging a low-voltage battery and providing power to the on-board systems (electronic control systems, security systems, etc.) is difficult to overestimate. Therefore ensuring the safe operation of the voltage converter is an extremely important task. There are many factors and phenomena that negatively affect the magnitude of the voltage value in the high-voltage circuit of an electric vehicle, and hence the input voltage of the conversion devices. The problem of electrical equipment reliability in a vehicle with electric drive was raised to be solved by monitoring and maintaining the required power supply parameters. The purpose of the study was to develop and research the system of protection against low and high input voltage at the conversion device input. Methodology and research methods. For the theoretical level of research, the method of analysis and synthesis was used, for the empirical one the material modeling method was applied. Scientific novelty and results. The structural and circuit diagrams of the undervoltage and increased input voltage protection device were developed on the basis of the TLV431 chip for the DC/DC converter modules equipped with a switching control input. The analytical calculations for this system and its components were tested in the Proteus computer simulation software package. The factors that negatively affected the voltage stability in a high-voltage electric vehicle system were also indicated. Practical significance. The results of the study can be applied to a reducing converter individually as part of an electric vehicle equipment, by calculating a variant of the protection circuit for the required voltage ranges.