A high efficiency DC - DC power module scheme DC/DC power module is widely used in the design of electronic products, the secondary power supply, it will be a power supply output voltage of a single quadratic transformation, into various need voltage, provided to the chip. Because the module is small size, with high power density requirements, at the same time the work environment is relatively poor, so requires the high reliability; power module general working temperature is -20 ~ 55 ℃, MTBF (MTBF) requirements in more than 200000 hours. This paper puts forward a kind of based on UC3843 chip implementation scheme of DC/DC power module simple circuit, reliable work, high conversion efficiency.