Low leakage IO circuit and associated apparatus
AssigneeMStar Semiconductor, Inc.
InventorChun-Wen Yeh
Life of this patent
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Abstract
A low-leakage IO circuit is provided. The IO circuit includes an impedance path between a pad and a power supply. The impedance path bypasses a signal path of the pad and includes a switch circuit. According to a relationship between voltages of the power supply and the pad of the IO circuit, the switch circuit selectively conducts the impedance path. When the power supply provides power normally, the switch circuit conducts the impedance path to provide a pull-up resistor between the pad and the power supply. When the power supply provides no power and its voltage is lower than a voltage of the pad, the switch circuit disconnects the conducting path to effectively reduce power leakage.
Claims18
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.
A chip, comprising:
- a pad;
- an impedance circuit, coupled between a 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;
- 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 the power supply to the pad.
Dependencies are inferred from the claim text.