A driving circuit includes at least a driving unit. The driving circuit includes a first bias component, a second bias component, and four metal-oxide-semiconductor (MOS) transistors. The first bias component has a first node coupled to a first reference voltage and a second node for outputting a first bias current. The second bias component has a first node for draining a second bias current and a second node coupled to a second reference voltage different from the first reference voltage. Each of the MOS transistors has a control node for receiving one of input signal pairs, a node coupled to one of the bias components and another node coupled to one of the output ports of the driving circuit. The four MOS transistors are of a same conductive type.