A power supply unit (100, 200) comprising: a plurality of alternating current to direct current (AC/DC) converters (110, 210) coupled together to redundantly convert an input voltage to a first DC voltage, wherein a given AC/DC converter (110, 210) includes an input connector at its front face to receive the input voltage, and wherein the input connector occupies greater than one third of a frontal area of the front face of the given converter (110, 210); wherein the given AC/DC converter (110, 210) is fanless and modular, and further includes a rear coupling (119, 219) at its rear face opposite its front face, characterized in that the power supply unit (100, 200) further comprises a cooling module including a front coupling at a front face of the cooling module that is configured to interface with the rear coupling (119, 219) of the plurality of AC/DC converters (110, 210); wherein the cooling module is configured to - provide cooling for the power supply unit (100, 200, 300), i.e. cooling for the AC/DC converters (110, 210, 310) as well as the cooling module (230, 330) itself, - receive the first DC voltage at the front coupling of the cooling module (230, 330) from the rear coupling (119, 219) of the AC/DC converters (110, 210, 310), and either - pass the first DC voltage from the AC/DC converters (110, 210, 310) through the front coupling (239, 339) to a rear of the cooling module (230, 330), or - convert the first DC voltage to a second output voltage (204, 504) at the rear of the cooling module (230, 330). a plurality of alternating current to direct current (AC/DC) converters (110, 210) coupled together to redundantly convert an input voltage to a first DC voltage, wherein a given AC/DC converter (110, 210) includes an input connector at its front face to receive the input voltage, and wherein the input connector occupies greater than one third of a frontal area of the front face of the given converter (110, 210); wherein the given AC/DC converter (110, 210) is fanless and modular, and further includes a rear coupling (119, 219) at its rear face opposite its front face, characterized in that the power supply unit (100, 200) further comprises a cooling module including a front coupling at a front face of the cooling module that is configured to interface with the rear coupling (119, 219) of the plurality of AC/DC converters (110, 210); wherein the cooling module is configured to - provide cooling for the power supply unit (100, 200, 300), i.e. cooling for the AC/DC converters (110, 210, 310) as well as the cooling module (230, 330) itself, - receive the first DC voltage at the front coupling of the cooling module (230, 330) from the rear coupling (119, 219) of the AC/DC converters (110, 210, 310), and either - pass the first DC voltage from the AC/DC converters (110, 210, 310) through the front coupling (239, 339) to a rear of the cooling module (230, 330), or - convert the first DC voltage to a second output voltage (204, 504) at the rear of the cooling module (230, 330). - provide cooling for the power supply unit (100, 200, 300), i.e. cooling for the AC/DC converters (110, 210, 310) as well as the cooling module (230, 330) itself, - receive the first DC voltage at the front coupling of the cooling module (230, 330) from the rear coupling (119, 219) of the AC/DC converters (110, 210, 310), and either - pass the first DC voltage from the AC/DC converters (110, 210, 310) through the front coupling (239, 339) to a rear of the cooling module (230, 330), or - convert the first DC voltage to a second output voltage (204, 504) at the rear of the cooling module (230, 330).