新材料打开电源转换设计的选择

　　新材料打开电源转换设计的选择

　　旨在提高能源效率的开关电源设计人员面临着一些权衡，这些问题往往涉及到成本和复杂性的增加，或者如果与传统的硅功率器件相匹配，则会降低功率密度。宽带隙材料，如碳化硅（SiC）提供了一个新的自由度在功率转换器的设计，尤其是在高功率额定需要。

　　宽禁带和临界电场导致较高的击穿电压：比硅高十倍。这使得可以制造更薄和更小的器件，这样即使SiC的载流子迁移率比硅的差，但它可以携带更少损耗的更多电流。最重要的是，高得多的热导率会大大提高功率密度。碳化硅器件可以在150℃以上的结温下可靠地运行，有助于节省散热片和包装成本。

　　该技术仍在发展，并没有一个完整的设备组合，但有越来越多的二极管和第一个商业MOSFET已经启动。本文将提供功率转换碳化硅产品概述，包括设备从克里（cmf10120d，cmf20120d，csd01060），英飞凌科技（idd03sg60c），IXYS（fbs16-06sc）、ROHM（scs120ke2c）和STMicroelectronics（stpsc2006cw）。

　　Tradeoffs are commonplace in power-component design. Properties that are good for energy efficiency – such as low on-resistance – can lead to process and design decisions that result in less desirable characteristics such as reduced breakdown voltage. Although silicon remains the material of choice for most power devices， other options are appearing that will make it possible to reduce the effects of these tradeoffs. Options have opened up thanks to the arrival of two wide band-gap materials now being actively investigated and productized by manufacturers. One is gallium nitride （GaN） and the other is silicon carbide （SiC）。

　　The band-gaps of GaN and SiC are around three times larger than the band-gap of conventional silicon. The critical field rating is approximately ten times higher than that of silicon. This leads not just to higher breakdown voltages， but better performance at high temperatures， which reduces the cost of power-supply products by allowing the use of smaller or even no heatsinks， as well as lower leakage.