Patent ID: 8368373

Claim:
A control circuit of power supply unit which controls a voltage value of output voltage corresponding to an instruction from an external unit, comprising: an interface control portion which receives first voltage setting information sent from the external unit through a communication line, the first voltage setting information being information on a first voltage difference between a high side and a low side in a supply voltage of a load; and a voltage adjusting portion which adjusts real voltage information based on the first voltage setting information and second voltage setting information which is information on a second voltage difference between a terminal and a ground voltage, wherein the voltage adjusting portion comprises an operating portion for executing operation between the first voltage setting information and the second voltage setting information, wherein the operating portion comprises an adding portion for adding half of the first voltage difference and the second voltage difference or a subtracting portion for subtracting half of the first voltage difference from the second voltage difference, and wherein the voltage value of the output voltage is controlled based on the real voltage information outputted from the voltage adjusting portion.