The purpose of this thesis studies a DC to DC converter technology that meets the increasing demand of a high efficiency and low build cost converter architecture for the portable electronics devices. Traditional hysteretic control converter is easy to implement with low build cost, but the disadvantages come with it is the varying switching frequency with the input and output condition changes. This thesis investigates the characteristics of hysteretic control circuits for the DC to DC converters, including transient response, switching frequency stability, and so forth. By using analysis, simulation, implementation, and comparison, a DC to DC converter with a simple hysteretic control circuit and a good transient response can be obtained.