Patent ID: RE44180

Claim:
A DC/DC converter comprising: a switching unit to output a waveform having a first rising time according to a plurality of PWM signals corresponding to a plurality of power sources; a smoothing circuit to output a DC power according to the waveform output from the switching unit; a variable resistor connected to the switching unit to adjust a switching time of the waveform output from the switching unit and to adjust one of the plurality of power sources supplied to the switching unit ; and a variable resistor controller to sense a load current from an output terminal of the smoothing circuit and to set a resistance of the variable resistor according to the sensed current so that the switching unit generates an adjusted switching time according to the adjusted one of plurality of power sources , wherein the smoothing circuit outputs another waveform having a second rising time according to the set resistance of the variable resistor and according to the adjusted switching time of the waveform output from the switching unit .