| 摘要 |
PROBLEM TO BE SOLVED: To provide a switching regulator in which power factor can be improved without increasing the size or cost. SOLUTION: Between the joint Z of the primary winding Np of a transformer 6 and a switching element Q and the joint Y of a diode D1 and a smoothing capacitor C1, a second diode D2 and a choke coil CH are connected in series and a third diode D3 for commutating the choke coil CH is connected between the joint of the D2 and CH and the negative terminal of the smoothing capacitor C1. A steep current flowing through D2 is limited by the choke coil CH such that a current flows continuously from the choke coil CH through the commutation diode D3 thus charging the smoothing capacitor C1 even if the switching element Q is turned on.
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