Patent 9608528 was granted and assigned to Hitachi on March, 2017 by the United States Patent and Trademark Office.
Objects of the invention are not to receive influence of an electromagnetic noise from a transformer and to reduce a possibility of breakage caused by shock or vibration. In a DC-DC converter apparatus of the invention, a shielding metal frame 300 is placed between a transformer 250 and a control circuit board assembly 240A housed in a case 101. A plate spring 311 attached to the metal frame 300 is pressed to cores 251 of the transformer 250 to fix the transformer 250 to a bottom portion 101a of the case 101. Heat generated from the transformer 250 is transmitted to the metal frame 300 and the bottom portion 101a of the case 101 and is then radiated.