Owing to the rapid increase in the use of small- and medium-sized motors at various industry, the reliability of the electronic control systems is emerging as an issue. Accordingly, research on a method that guarantees reliable motion of motors by selecting appropriate gate resistance of the driver part and that contributes as a solution to the thermal issue and EMC(Electromagnetic Compatibility) in terms of design was conducted. Among methods that increase the reliability of motor drivers, one involving the calculation of an optimal gate resistance value is the most efficient in cost aspects without he added hardware or the application of a complex motor control algorithm. Therefore, this study proposed the process of finding optimal gate resistance of the driver circuit. An approach was made to find a safe operation area about switching, which has considered only partially, and a practical experiment was carried out through the evaluation board to prove the proposed method. As a result, although the estimated range and experimental results had slight deviation, we proved that it could be used as a method to find the optimal resistance value.