Supplanting linears

摘要

Despite the emergence of cost-effective alternatives, many OEMs have persisted in using line-frequency transformers (linears) in low-power battery chargers and ac adapters. This is largely due to inertia, as many OEMs nave taken an "if it isn't broken, don't fix it" attitude toward their power supplies, despite the obvious size/weight advantages of switchers. However, because of their high eddy-current and winding-conduction losses, existing linear designs generally fail to comply with upcoming mandatory energy-efficiency standards for external power supplies. In the resulting redesign cycle (which is already well underway), manufacturers will be inclined to choose switched-mode designs for two reasons.