FIELD: electrical engineering. SUBSTANCE: device has first power supply unit, which provides first voltage level; second power supply unit, which provides second voltage level, which is less than first output voltage level; back-up power supply unit, which provides back-up load voltage; charge current control unit, which sets first voltage level and controls charging current which provides application of power to back-up power supply unit according to capacitance of back-up power supply unit. In addition device has reverse-current protection unit, which is connected between second power supply unit and output unit, which is connected to device output; overload protection unit, which is connected between back-up power supply unit and output unit and is designed for protection of back-up unit against overload; and relay unit, which is excited by first voltage level and which provides channel for output of back-up voltage to output unit, when first and second voltage levels are switched off. EFFECT: increased duration of accumulated power operations, when input voltage is switched off. 3 cl, 2 dwg
