A display device with a display region and a non-display region surrounding the display region, the display device comprising: a first substrate and a second substrate. The first substrate comprises: a first insulating substrate; a gate line formed on the first insulating substrate; a pixel thin film transistor formed on the display region and electrically connected to the gate line; a pixel electrode electrically connected to the pixel thin film transistor; a gate driver formed on the non-display region and connected to the gate line; and a direct current (DC)/DC converter formed on the non-display region and having a capacitance part. The capacitance part includes: a first capacitance part with a first electrode, a first dielectric layer, and a second electrode; and a second capacitance part with the second electrode, a second dielectric layer, and a third electrode.