How to choose a good non-isolated?(3)


DC Module power

There are many packaging methods of custom-make supply, including those conforming to international standards and non-standard ones. For the products of the same company, the same power products have different packages, and the same package has different powers. So how to choose the packaging method? There are mainly three aspects: ① the volume should be as small as possible under certain power conditions, so as to give more space and more functions to other parts of the system; ② Try to select products that conform to international standard packaging. Due to good compatibility, it is not limited to one or two suppliers; ③ It shall be scalable to facilitate system capacity expansion and promotion. Select a package. Due to the improvement of the system's functional upgrading requirements for power supply power, the power module package remains unchanged, and the system circuit board planning does not need to be changed, which greatly simplifies the upgrading of products and saves time.

Distributed Power Supply System
The distributed power supply system uses low-power modules and large-scale control integrated circuits as basic components, and uses the latest theoretical and technological achievements to form a building block-type, intelligent high-power power supply, so that the strong and weak currents are closely combined and the high power is reduced. Components, high-power devices (centralized) development pressure, improve production efficiency.

3. Temperature scale and derating application

Generally, non-isolated of manufacturers have several temperature scale products to choose from: commercial grade, industrial grade, military grade, etc. when selecting custom-make supply, the actual operating temperature scale must be considered. Because of different temperature grades, different materials and manufacturing processes, the price varies greatly. Improper selection will also affect the application, so we have to consider carefully. There are two selection methods: one is based on the applied power and packaging method. If the actual applied power is close to the rated power under the condition of a certain volume (packaging method), then the nominal temperature scale of the module must be strictly satisfied with the actual needs or even have a little margin. Second, choose according to the temperature scale. If you choose a product with a smaller temperature scale due to cost considerations, but sometimes the temperature is forced to the limit, what should you do? Derating application. That is, select products with larger power or packaging, so that "big horse pulls small car", and the temperature rise is lower, which can alleviate this opposition to a certain extent. The derating share varies with the power level, and is generally 3 ~ 10W / ℃ above 50W. In short, either choose products with wide temperature scale, more abundant power utilization and smaller package, but the price is higher; Or choose products of general temperature scale, with lower price, larger power margin and packaging mode. A compromise should be considered.