如何相移可以幫助改善性能的DC / DC轉換器

　　。現代電子系統板的集成電路如FPGA，DSP，微處理器，存儲器和ASIC芯片。此外，還有音頻放大器和射頻功率放大器模塊板上與聲音和無線通信。這種電路板上的每個器件或模塊對電壓和電流有不同的要求。因此，在分布式電源架構，這些半導體器件和模塊是由多種負荷切換點（POL）供電的直流/直流轉換器，獲得他們的輸入從一個共同的總線電壓以產生所需的電壓或電壓的半導體集成電路和模塊。

　　從一個單一的源產生一系列的調節直流輸出電壓施加高均方根（RMS）電流紋波和噪聲問題的直流輸入源。為了解決噪聲問題，設計師通常使用額外的成本輸入濾波。由于每個開關轉換器使用不同的開關頻率，拍頻100赫茲和23千赫之間產生的，它可以降低系統音頻放大器的性能。

　　Recently， Intersil published a white paper1 describing how the input RMS current ripple and noise can be minimized by preventing the on-time overlapping of these multiple， on-board DC/DC converters using phase-shifting techniques. In reality， this technique also improves EMI and eliminates the need for input filtering， while tackling the problems linked with beat frequencies.

　　This article examines how multiple DC/DC buck regulators are organized in a master/slave configuration using phase-shifting time delays to improve the noise performance on the source input of these on-board DC/DC converters. It also demonstrates the implementation of the phase-shifting time delay technique using Intersil’s synchronous buck regulator ISL8018， which is tailored for this design. In addition， by synchronizing multiple DC/DC converters using the same clock， the article also shows that beat-frequency problems can be eliminated from the system.