Input/output circuit, input/output network, and input/output system including the same
View Patent ↗An input/output circuit may include a driving unit including a first transistor coupled between a power supply voltage and a first node, and a second transistor coupled in series with the first transistor through the first node at an end of the second transistor. The input/output circuit may include switch elements coupled in parallel to a second node at another end of the second transistor, and the switch elements configured to be selectively turned on in an input operation and an output operation.
1. An input/output circuit comprising:
a driving unit including a first transistor coupled between a power supply voltage and a first node, and a second transistor coupled in series with the first transistor through the first node at an end of the second transistor; and
switch elements coupled in parallel to a second node at another end of the second transistor, and the switch elements configured to be selectively turned on in an input operation and an output operation.
2. The input/output circuit according to claim 1 , wherein a switch element which is turned on in the output operation provides a ground voltage to the second node.
3. The input/output circuit according to claim 2 , wherein the is driving unit inputs and outputs data from and to a pad through the first node.
4. The input/output circuit according to claim 3 , further comprising:
a reference voltage providing unit configured to provide a reference voltage to one end of a switch element which is turned on in the input operation; and
a capacitor coupled to the reference voltage providing unit.
5. The input/output circuit according to claim 3 , wherein the first and second transistors perform a pull-up operation and a pull-down operation, respectively, in response to data which is outputted in the output operation.
6. The input/output circuit according to claim 3 , further comprising:
an electrostatic discharge protection circuit disposed between the pad and the first node.
7. The input/output circuit according to claim 3 , wherein at least one of the switch elements has a larger size than the second transistor.
8. An input/output network including a plurality of input/output circuits coupled with a plurality of transmission lines and input/output data through pads, each input/output circuit comprising:
a driving unit including a first transistor coupled between a first voltage and a first node, and a second transistor coupled between the first node and a second node;
a fourth transistor coupled between the second node and a second voltage, and configured to be turned on in a first operation and provide the second voltage to the second node;
a third transistor coupled between the second node and a third node, and configured to be turned on in a second operation and function as a resistor coupled to the second node; and
a differential amplifier configured to receive inputs from the first node and a first node of another input/output circuit,
wherein third nodes of the plurality of input/output circuits are coupled in common.
9. The input/output network according to claim 8 , wherein three input/output circuits are included.
10. The input/output network according to claim 9 , wherein the first voltage corresponds to a power supply voltage, and the second voltage corresponds to a ground voltage.
11. The input/output network according to claim 10 , wherein the first operation corresponds to an input operation, and the second operation corresponds to an output operation.
12. The input/output network according to claim 11 , wherein, in the output operation, the first and second transistors perform a pull-up operation and a pull-down operation, respectively, in response to data to be outputted.
13. The input/output network according to claim 11 , wherein, in the input operation, at least one of the input/output circuits does not receive input data through the pad.
14. An input/output system comprising:
an input/output control circuit configured to generate input/output control signals; and
an input/output circuit including switch elements coupled in parallel to a lower end of a pull-down element disposed in a driving unit, and the switch elements configured to be selectively turned on according to the input/output control signals.
15. The input/output system according to claim 14 , wherein the switch elements comprise:
a first transistor configured to be turned on in an input operation based on the input/output control signals; and
a second transistor configured to be turned on in an output operation based on the input/output control signals.
16. The input/output system according to claim 15 , wherein the input/output control circuit generates the input/output control signals according to output data and an operation mode.
17. The input/output system according to claim 15 , wherein at least one of the first and second transistors has a size larger than the pull-down element disposed in the driving unit.
18. The input/output system according to claim 15 , wherein the pull-down element is turned on in the input operation based on the input/output control signals.
19. The input/output system according to claim 15 , further comprising:
a reference voltage providing unit configured to provide a reference voltage to a terminal other than a terminal through which the third transistor is coupled with the pull-down element; and
a capacitor coupled between the terminal to which the reference voltage providing unit is coupled and a ground voltage.
20. The input/output system according to claim 15 , wherein the second transistor provides the ground voltage to the pull-down element in response to the input/output control signals.