US 7,321,224 B2
DC-DC converter with clamping capacitor and output winding for reduced output voltage ripple
Kazuyuki Iwamoto, Iwata-gun (Japan); and Masaya Yamashita, Iwata-gun (Japan)
Assigned to Minebea Co., Ltd., Nagano (Japan)
Filed on May 25, 2005, as Appl. No. 11/136,495.
Claims priority of application No. 2004-186549 (JP), filed on Jun. 24, 2004.
Prior Publication US 2005/0286272 A1, Dec. 29, 2005
Int. Cl. G05F 1/253 (2006.01); G05F 1/613 (2006.01); G05F 1/00 (2006.01)
U.S. Cl. 323—262  [323/282; 323/229; 323/222] 8 Claims
OG exemplary drawing
 
1. A DC-DC converter comprising:
a main switching element;
an auxiliary switching element;
a rectifier diode;
a choke coil;
an output capacitor;
a clamping capacitor;
a first diode connected in parallel to the clamping capacitor; and
a resonance coil,
wherein the resonance coil includes first and second windings, the main switching element has one terminal thereof connected to one terminal of a DC power supply and has an other terminal thereof connected to one terminal of the first winding, the choke coil has one terminal thereof connected to one terminal of the second winding and has an other terminal thereof connected to one terminal of the output capacitor, the rectifier diode has one terminal thereof connected to a connecting portion of the first and second windings and has an other terminal thereof connected to an other terminal of the output capacitor and also to an other terminal of the DC power supply, and a series circuit including the auxiliary switching element and the clamping capacitor is provided between the other terminal of the DC power supply and a connecting portion of the main switching element and the first winding, whereby a step-down operation is performed.