| Abstract |
Since January 96, the European equipment manufacturers have to comply with the fECI 000-3-2 standard The mandatory compliance pushed many off-line Switched Mode Power
Supply (SMPS) designers to use a Boost Power Factor Corrector (PFC) as preregulator stage. Below 300W of power capability, two alternative approaches can comply with the standard by limiting the cost impact on the overall converter. A first approach consists in transforming conventional SMPS topologies into "Inherent High
Power Factor" (IHPF) structures which still need a serial coil. These IHPF topologies easily comply with all classes of the standard while achieving Power Factor values above 0.95. The second approach takes advantage from the standard Class D definition through a
1 00/120Hz "line current shaping". It mainly allows to escape from the constraining Class D to the much more favourable Class A. Such a current shaping based front-end circuits can achieve PF-values up to 0.8 without any coil. |
