外文资料翻译---开关模式中功率半导体的应用(编辑修改稿)

外文资料翻译---开关模式中功率半导体的应用(编辑修改稿)内容摘要：

t: inverter For many years the world of power supply design has seen a gradual movement away from the use of linear power supplies to the more practical switched mode power supply (.). The linear power supply contains a mains transformer and a dissipative series regulator. This means the supply has extremely large and heavy 50/60 Hz transformers, and also very poor power conversion efficiencies, both serious drawbacks. Typical efficiencies of 30% are standard for a linear. This pares with efficiencies of between 70% and 80%, currently available using . designs. Furthermore, by employing high switching frequencies, the sizes of the power transformer and associated filtering ponents in the . are dramatically reduced in parison to the linear. For example, an . operating at 20 kHz produces a 4 times reduction in ponent size, and this increases to about 8 times at 100 kHz and above. This means an . design can produce very pact and lightweight supplies. This is now an essential requirement for the majority of electronic systems. The supply must slot into an ever shrinking space left for it by electronic system designers. At the heart of the converter is the high frequency inverter section, where the input supply is chopped at very high frequencies (20 to200kHz using present technologies) then filtered and smoothed to produce dc outputs. The circuit configuration which determines how the power is transferred is called the TOPOLOGY of the ., and is an extremely important part of the design process. The topology consists of an arrangement of transformer, inductors, capacitors and power semiconductors. Regulation of the output to provide a stabilized DC supply is carried out by the control / feedback block. Generally, most . systems operate on a fixed frequency pulse width modulation basis, where the duration of the on time of the drive to the power switch is varied on a cycle by cycle basis. This pensates for changes in the input supply and output load. The output voltage is pared to an accurate reference supply, and the error voltage produced by the parator is used by dedicated control logic to terminate the drive pulse to the main power switch/switches at the correct instance. Correctly designed, this will provide a very stable AC output supply. In most applications, the . topology contains a power transformer. This provides isolation, voltage scaling through the turns ratio, and the ability to provide multiple outputs. However, there are nonisolated topologies (without transformers) such as the buck and the boost converters, where the power processing is achieved by inductive energy transfer alone. All of the more plex arrangements are based on these nonisolated types. ON Semiconductor has been a key supplier of semiconductor products for switching power supplies since we introduced bipolar power transistors and rectifiers designed specifically for switching Efficien。