| 摘要 |
A cost effective solution for power factor correction in power devices operating at two widely separated input voltages comprises two unequal power rails. One power rail is optimized for operation at high line voltage only, while the other power rail is designed only for low line voltage. When operating at high line voltage, the second rail is disabled. At low line, both power rails are enabled but by virtue of unequal boost inductors, the high line power rail handles only about 30% of the power while the low line power rail handles the remaining power. Hence, the efficiency at high line voltage is maximized. As the inductance used in the high line power rail is much higher in value, it stays in continuous conduction mode for all load conditions and hence the power factor is significantly improved.
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