Patent ID: 8896159

Claim:
A low leakage input/output (TO) circuit, comprising: a power supply; a pad; an impedance circuit, coupled between the power supply and the pad, the impedance circuit comprising a first node, a second node, and a switch circuit coupled between the first node and the second node; and a control circuit, coupled between the power supply and the pad, for controlling the switch circuit to conduct the first node and the second node according to a relationship between a power supply voltage and a pad voltage; wherein the switch circuit comprises a controlled end, and the control circuit comprises a control end coupled to the controlled end, and the control circuit controls the switch circuit to stop conducting when the pad voltage is greater than the power supply voltage, and controls the switch circuit to conduct when the pad voltage is not greater than the power supply voltage; and wherein, the switch circuit selectively conducts the first node to the second node, so as to control the impedance circuit to selectively conduct voltage from the power supply to the pad.