A method of producing an economical DC/DC converter that efficiently produces a relatively low output voltage and operates in a high ionizing radiation dose environment such as found in spacecraft and particle accelerator applications. That is, the converter comprises two P-channel FETs, a switching means for switching conductivity between the two P-channel FETs, and output means for outputting an output voltage. The output voltage being a step-down voltage that is unaffected by high-ionizing radiation such that is found in space or particle accelerators.