| 摘要 |
A half-bridge converter with improved power factor has a voltage smoothing capacitor (Cd), a switching unit (330), a power factor improving unit (310) and a bridge diode unit (320) for transmitting energy to the voltage smoothing capacitor (Cd) and providing a current path to the power factor improving unit (310). The switching unit (330) has two switches (S1, S2) connected in series between the ends of the voltage smoothing capacitor (Cd). The power factor improving unit (310) feeds the voltage of a common connection point (CTRL) of the two switches (S1, S2) back to a common connection point of a pair of input capacitors (Cfl, Cf2) connected in series, so as to change input current according to the magnitude of input voltage. Conducting loss occurring in the switching unit (330) decreases and the power factor is improved. <IMAGE>
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