Patent ID: 8669803

Claim:
A level shifter, comprising: an input side logic unit for receiving an input signal and generating a complementary input signal pair, wherein the input signal and the complementary input signal pair are operated between a core voltage and a ground voltage; a latching unit comprising a first P-type transistor, a second P-type transistor, and a load unit, wherein the first P-type transistor has a source terminal receiving an input/output voltage, a drain terminal connected to a first node, and a gate terminal connected to a second node, wherein the second P-type transistor has a source terminal receiving the input/output voltage, a drain terminal connected to the second node, and a gate terminal connected to the first node, wherein the load unit is connected to the first node and the second node, and the first node and the second node generate a complementary output signal pair according to the complementary input signal pair; and an output side buffering unit connected to the second node for generating the complementary output signal pair, so that the complementary output signal pair is operated between the input/output voltage and the ground voltage, wherein the latching unit further comprises a first switching unit and a second switching unit, wherein the first switching unit comprises a first switch element and a second switch element, and the second switching unit comprises a third switch element and a fourth switch element, wherein the first switch element and the second switch element are serially connected between the input/output voltage and the first node, the first switch element has a control terminal receiving one signal of the complementary output signal pair, and the second switch element has a control terminal receiving one signal of the complementary input signal pair, wherein the third switch element and the fourth switch element are serially connected between the input/output voltage and the second node, the third switch element has a control terminal receiving the other signal of the complementary output signal pair, and the fourth switch element has a control terminal receiving the other signal of the complementary input signal pair.