Brick DC / DC converters working condition is worsening, even though these modules as a generic product has not much room for development, but vendors still doing further efforts to fully tap the potential of these devices. Currently, the market for improving the power density, efficiency and other requirements focused on small-scale converter, the new release of products are rarely more than a half brick size converters. Of course, to minimize the size is not the most urgent need, in fact, the current market-dominant products are mainly one-eighth brick. From a technical point of view, wide and narrow input, modulation and non-modulated output, wireless applications as well as Power over Ethernet (PoE) applications concern the compatibility of a hot spot.