Switching regulators are used as replacements for linear regulators when higher efficiency, smaller size or lighter weight are required. Despite the reduction in size, the power supply topology itself and the requirement for electromagnetic interference suppression in commercial designs result in a usually much greater component count and corresponding circuit complexity. This is because it operates on the switching frequency which ranges from several 100KHz to several MHz in contrast to the 50-60Hz which is typical for the mains AC frequency. Switched-mode power supplies can also be substantially smaller and lighter than a linear supply because the transformer can be much smaller. This higher power conversion efficiency is an important advantage of a switched-mode power supply. In contrast, a linear power supply regulates the output voltage by continually dissipating power in the pass transistor. Voltage regulation is achieved by varying the ratio of on-to-off time (also known as duty cycles). A hypothetical ideal switched-mode power supply dissipates no power. Unlike a linear power supply, the pass transistor of a switching-mode supply continually switches between low- dissipation, full-on and full-off states, and spends very little time in the high dissipation transitions, which minimizes wasted energy. Like other power supplies, an SMPS transfers power from a DC or AC source (often mains power, see AC adapter) to DC loads, such as a personal computer, while converting voltage and current characteristics. An adjustable switched-mode power supply for laboratory use
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |