Electrostatic discharge protection circuit
It is desired to achieve a high ESD protection performance by a small area circuit. An electrostatic discharge protection circuit includes: protection circuits, wherein each protection circuit includes a MOS transistor; and a trigger circuit configured to supply a trigger signal to a gate electrode of the MOS transistor of each protection circuit in response to a surge voltage between a low potential node and a high potential node. Each protection circuit is configured to electrically connect the low potential node and the high potential node to one another when the trigger signal is supplied to the gate electrode. The gate electrode of each protection circuit is connected to a resistive element having larger resistance value than Rmax, supposing that Rmax is a largest parasitic resistance between each of the plurality of protection circuit and an output of the trigger circuit.
1. An electrostatic discharge protection circuit comprising:
a plurality of protection circuits, wherein each of the plurality of protection circuits includes a MOS transistor; and
a trigger circuit configured to supply a trigger signal to a gate electrode of the MOS transistor of each of the plurality of protection circuits in response to a surge voltage between a low potential node and a high potential node,
wherein each of the plurality of protection circuits is configured to electrically connect the low potential node and the high potential node to one another when the trigger signal is supplied to the gate electrode of the MOS transistor,
wherein the gate electrode of the MOS transistor of each of the plurality of protection circuits is connected to a resistive element having a larger resistance value than Rmax,
wherein Rmax is a largest parasitic resistance between each protection circuit of the plurality of protection circuits and an output of the trigger circuit, and
wherein the MOS transistor of a predetermined protection circuit among the plurality of protection circuits includes:
a plurality of gate electrodes;
a plurality of source electrodes; and
a plurality of drain electrodes respectively adjacent to one of the plurality of source electrodes across from one of the plurality of gate electrodes,
the plurality of gate electrodes being connected in series to the resistive element.
2. The electrostatic discharge protection circuit according to claim 1 , wherein each of the plurality of protection circuits comprises a conductive member having a first end connected to the gate electrode, and a second end connected to the resistive element.
3. The electrostatic discharge protection circuit according to claim 1 , wherein the gate electrode of the MOS transistor of each protection circuit of the plurality of protection circuits is formed by a material obtained by siliciding the material forming the resistive element.
4. An integrated circuit chip comprising:
the electrostatic discharge protection circuit according to claim 1 ; and
a protection target circuit connected in parallel to the electrostatic discharge protection circuit and configured to use the low potential node and the high potential node.
5. The electrostatic discharge protection circuit according to claim 1 , wherein the gate electrode comprises a silicided surface.
6. The electrostatic discharge protection circuit according to claim 1 , wherein the resistive element comprises a resistance value that is 10 times or more greater than Rmax.
7. The electrostatic discharge protection circuit according to claim 1 , wherein the trigger circuit comprises a resistive element and a capacitive element, the resistive element and the capacitive element having an RC time constant, and
wherein the RC time constant determines a duration that the trigger circuit outputs the trigger signal.
8. The electrostatic discharge protection circuit according to claim 1 , wherein the trigger circuit comprises a buffer that amplifies the trigger signal.
9. The electrostatic discharge protection circuit according to claim 1 , wherein the gate electrode of the MOS transistor of each of the plurality of protection circuits comprises the resistive element.
10. The electrostatic discharge protection circuit according to claim 9 , wherein the gate electrode is partially silicided.
11. The electrostatic discharge protection circuit according to claim 1 , wherein the plurality of protection circuits comprises:
a first protection circuit connected through a first parasitic resistance to the output of the trigger circuit; and
a second protection circuit connected through a second parasitic resistance to the output of the trigger circuit.
12. The electrostatic discharge protection circuit according to claim 11 , wherein the second parasitic resistance comprises a first end connected to the resistive element of the second protection circuit and a second end connected to the first parasitic resistance.
13. The electrostatic discharge protection circuit according to claim 11 , wherein the output of the trigger circuit is connected in series to the first parasitic resistance and the second parasitic resistance.
14. The electrostatic discharge protection circuit according to claim 1 , wherein the resistive element of each of the plurality of protection circuits comprises substantially a same resistance.