A DC-to-DC converter and a method thereof is provided. The DC-to-DC converter includes a power supply for providing a first direct current, a first capacitor, a first switch assembly for converting the first direct current into a first alternating current, a transformer for converting the first alternating current to a second alternating current, a rectifying circuit for converting and rectifying the second alternating current to a second direct current, a filtering circuit, and a range winding assembly for adjusting the output voltage of the second direct current in response to the voltage drop of the first direct current.