設計多相、大功率降壓變換器的優(yōu)點

　　雖然單相降壓控制器適用于低壓轉換器應用，其電流要求高達約25 A，但當負載電壓低且電流要求較高時，功耗和效率開始成為一個問題。尤其是新一代高速處理器，其工作電壓低于2 V，需要50 A或更高的處理數據。多相降壓變換器有望解決這一問題。

　　在這種應用中使用多相技術的主要好處是，它們提供更高的效率，從較低的過渡損耗，更低的輸出紋波電壓，更好的瞬態(tài)性能，以及較低的紋波電流額定值的輸入電容器。

　　一些電力半導體供應商開發(fā)了多相降壓控制器，包括只需少量無源元件就能完成解決方案的集成解決方案。一些在這個空間的主要選手是國際整流器，Intersil，線性技術，集成產品、德克薩斯文書等等。

　　Benefits in detail

　　Texas Instruments has generated an application note1 that describes some of the benefits in detail and provides a design example to demonstrate the outlined capabilities. A typical two-phase converter with associated multiphase controller is shown in Figure 1. The corresponding waveform for the two phases at respective nodes is depicted in Figure 2. As described in the application note， the two phases are interleaved， which reduces ripple currents at the input and output. In addition， interleaving also reduces hot spots on a printed-circuit board （PCB） or a particular component. In reality， a two-phase buck converter reduces the current （rms） power dissipation in the MOSFETs and associated inductors by half， thereby significantly cutting transitional losses to improve conversion efficiency.