An I/O driving circuit comprising: a post driver (200, 300, 403, 503, 603), comprising: a first switch device (SW 1), comprising a first terminal coupled to an I/O voltage (V DDIO), and comprising a second terminal, wherein the first switch device (SW 1) provides an initial driving voltage (V di) at the second terminal of the first switch device; and a first voltage providing device (D vp1), comprising a first terminal coupled to the second terminal of the first switch device (SW 1), and comprising a second terminal, wherein the first voltage providing device (D vp1) is configured to provide a driving voltage at the second terminal of the first voltage providing device (V-vp1) via providing a voltage drop to the initial driving voltage (V di); and a pre-driver (401, 501, 601) comprising a plurality of pre-driving blocks (PDB_1, PDB_2, PDB_3, PDB_4), wherein at least one pre-driving block (PDB_2) is configured to generate a first control signal (CS_1) for controlling the first switch device (SW_1) and to operate at a first power domain (V_DDIO); and at least one other pre-driving block (PDB_3) is configured to generate a second control signal (CS_2) to control the first voltage providing device (D_vp1) and to operate at a second power domain (V_core); characterized in that an oxide layer of the first switch device (SW 1) is thicker than an oxide layer of the first voltage providing device (D vp1), thereby the first switch device (SW 1) can suffer a higher voltage. a post driver (200, 300, 403, 503, 603), comprising: a first switch device (SW 1), comprising a first terminal coupled to an I/O voltage (V DDIO), and comprising a second terminal, wherein the first switch device (SW 1) provides an initial driving voltage (V di) at the second terminal of the first switch device; and a first voltage providing device (D vp1), comprising a first terminal coupled to the second terminal of the first switch device (SW 1), and comprising a second terminal, wherein the first voltage providing device (D vp1) is configured to provide a driving voltage at the second terminal of the first voltage providing device (V-vp1) via providing a voltage drop to the initial driving voltage (V di); and a pre-driver (401, 501, 601) comprising a plurality of pre-driving blocks (PDB_1, PDB_2, PDB_3, PDB_4), a first switch device (SW 1), comprising a first terminal coupled to an I/O voltage (V DDIO), and comprising a second terminal, wherein the first switch device (SW 1) provides an initial driving voltage (V di) at the second terminal of the first switch device; and a first voltage providing device (D vp1), comprising a first terminal coupled to the second terminal of the first switch device (SW 1), and comprising a second terminal, wherein the first voltage providing device (D vp1) is configured to provide a driving voltage at the second terminal of the first voltage providing device (V-vp1) via providing a voltage drop to the initial driving voltage (V di); and a pre-driver (401, 501, 601) comprising a plurality of pre-driving blocks (PDB_1, PDB_2, PDB_3, PDB_4), wherein at least one pre-driving block (PDB_2) is configured to generate a first control signal (CS_1) for controlling the first switch device (SW_1) and to operate at a first power domain (V_DDIO); and at least one other pre-driving block (PDB_3) is configured to generate a second control signal (CS_2) to control the first voltage providing device (D_vp1) and to operate at a second power domain (V_core); characterized in that an oxide layer of the first switch device (SW 1) is thicker than an oxide layer of the first voltage providing device (D vp1), thereby the first switch device (SW 1) can suffer a higher voltage.