| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a PFC which is provided with an overheat protecting means for preventing a normal mode reactor constituting a noise filter from being overheated and is small and inexpensive. <P>SOLUTION: The power factor converter (PFC) is comprised of a commercial power supply 1, a bridge commutating circuit 2, the noise filter 3, a power-factor improving circuit 4 and the overheat protecting means 5b. The overheat protecting means 5b is constituted of a current detecting means comprised of a capacitor C3 and a resistor R5, a diode D2, a capacitor C4 and a resistor R6. A current detecting circuit is connected in parallel to a film capacitor C2 of the noise filter 3, an anode of the diode D2 is connected to a connection point between the capacitor C3 and the resistor R5, and a cathode is connected between a drain-current detecting means R2 of a switching element Q and a control circuit IC. The overheat protecting means 5b detects a disconnection of the film capacitor C2 constituting the noise filter 3 and controls heat generation of the normal mode reactor L1. <P>COPYRIGHT: (C)2010,JPO&INPIT |
