Output buffer of a source driver applied in a display

An output buffer of a source driver applied in a display, wherein the output buffer comprises:

• an upper buffer used to output a positive polarity signal for driving a data line of the graphic display over an upper supply range which is from a first voltage (V1) to a second voltage (V2), the upper buffer comprising a first upper supply terminal and a first lower supply terminal, wherein the first voltage (V1) is applied to the first upper supply terminal, and the second voltage (V2) is applied to the first lower supply terminal;
• and
• a lower buffer used to output a negative polarity signal for driving another data line of the graphic displayer over a lower supply rang which is from a third voltage (V3) to a fourth voltage (V4), the lower buffer comprising an second upper supply terminal and a second lower supply terminal, wherein the third voltage (V3) is applied to the second upper supply terminal, and the fourth voltage (V4) is applied to the second lower supply terminal;
• wherein V1>V2, V1>V4, V3>V2, and V3>V4, and the second voltage is equal to a common voltage minus a predetermined differential voltage, and the third voltage is equal to the common voltage (Vcom) plus the predetermined differential voltage (ΔV).