A power supply module for a power distribution cabinet that distributes power from one or more power sources to a plurality of internal cabinet modules, the power supply module including: a plurality of input terminals (12a, 12b, 12c), each input terminal is configured to be connected to a different power source, wherein availability of each of the plurality of power sources varies during operation of a vehicle; a plurality of output terminals (14a, 14b, 14c); the power supply module characterized by a first output terminal being connected to receive power only from a first one of the plurality of input terminals; and wherein a second one of the plurality of output terminals is connected to receive power only from a second one of the plurality of input terminals or a third one of the plurality of input terminals; and wherein a third one of the plurality of output terminals is connected to receive power only from either the first one of the plurality of input terminals, the second one of the plurality of input terminals, or the third one of the plurality of input terminals, and further including: a switching up/down converter that is connected to receive power from either the first input terminal, the second input terminal, or the third input terminal, and is configured to provide hold-up power to the first output terminal, the second output terminal, and the third output terminal, and wherein the second output terminal is connected to each of the first input terminal, the second input terminal, and the third input terminal to form a first diode OR circuit and the third output terminal is connected to each of the second input terminal and the third input terminal to form a second diode OR circuit. a plurality of input terminals (12a, 12b, 12c), each input terminal is configured to be connected to a different power source, wherein availability of each of the plurality of power sources varies during operation of a vehicle; a plurality of output terminals (14a, 14b, 14c); the power supply module characterized by a first output terminal being connected to receive power only from a first one of the plurality of input terminals; and wherein a second one of the plurality of output terminals is connected to receive power only from a second one of the plurality of input terminals or a third one of the plurality of input terminals; and wherein a third one of the plurality of output terminals is connected to receive power only from either the first one of the plurality of input terminals, the second one of the plurality of input terminals, or the third one of the plurality of input terminals, and further including: a switching up/down converter that is connected to receive power from either the first input terminal, the second input terminal, or the third input terminal, and is configured to provide hold-up power to the first output terminal, the second output terminal, and the third output terminal, and wherein the second output terminal is connected to each of the first input terminal, the second input terminal, and the third input terminal to form a first diode OR circuit and the third output terminal is connected to each of the second input terminal and the third input terminal to form a second diode OR circuit.