Power source device

A power source device comprising:

• an input line that receives a supply of a direct-current input voltage;
• an output line that is connected to a load;
• N inductors that correspond to N phases and each have one end connected to the output line, where N is an integer greater than zero and the N inductors are mounted to a main mounting surface of a printed circuit board;
• and
• N power modules that correspond to the N phases and each have an input pin, a switching
• pin, and a ground pin, the input pin being connected to the input line, the switching pin being connected to another end of a corresponding inductor, the ground pin being grounded, wherein:
• at least one of the N power modules is mounted on a sub-mounting surface that is opposite to the main mounting surface of the printed circuit board,
• the N inductors are linearly arranged in a first direction, wherein the first direction is an X-direction of the printed circuit board, and
• an i-th (i=1 to N) power module is disposed adjacently in a second direction, wherein the second direction is a Y-direction of the printed circuit board, to a corresponding i-th inductor, the second direction being perpendicular to the first direction.