ESD protection scheme for designs with positive, negative, and ground rails
View Patent ↗Apparatuses and systems for dissipating ESD events are provided. In an embodiment, an integrated circuit (IC) device, includes a ground rail, a positive supply rail, a negative supply rail, a circuit block, a plurality of contact pads, and a coupling system. Each of the ground rail, positive supply rail, negative supply rail, and the circuit block are coupled to a respective contact pad of the plurality of contact pads. The contact pad coupled to the circuit block is configured to swing from a voltage of the negative rail to a voltage of the positive rail. The coupling system couples each contact pad of the plurality of contact pads to all other contact pads of the plurality of contact pads, whereby an electrostatic discharge (ESD) event between two contacts pads of the plurality of contact pads can be dissipated.
1. An integrated circuit (IC) device, comprising:
a ground rail;
a positive supply rail;
a negative supply rail;
a circuit block;
a plurality of contact pads, wherein each of the ground rail, positive supply rail, negative supply rail, and the circuit block are coupled to a respective contact pad of the plurality of contact pads, wherein the contact pad coupled to the circuit block is configured to swing from a voltage of the negative rail to a voltage of the positive rail; and
a coupling system that couples each contact pad of the plurality of contact pads to all other contact pads of the plurality of contact pads, whereby an electrostatic discharge (ESD) event between two contact pads of the plurality of contact pads can be dissipated.
2. The IC device of claim 1 , wherein the coupling system comprises at least one of a diode or a clamp.
3. The IC device of claim 2 , wherein the clamp is a stacked clamp.
4. The IC device of claim 2 , wherein the clamp comprises a nmos transistor.
5. The IC device of claim 4 , wherein the nmos transistor is formed in an isolated p-well.
6. The IC device of claim 1 , wherein the ground rail, the positive supply rail, the negative supply rail, and the circuit block are part of a first segment of the IC device, wherein the IC device further comprises a second segment, the second segment comprising:
a second ground rail;
a second positive supply rail;
a second circuit block;
wherein each of the second ground rail, second positive supply rail, and the second circuit block are coupled to a respective contact of the plurality of contact pads.
7. The IC device of claim 6 , further comprising: a third ground rail, wherein the third ground rail couples the first ground rail to the second ground rail.
8. The IC device of claim 1 , wherein the coupling system comprises:
a first cell that couples the positive supply rail and the ground rail;
a second cell that couples the negative supply rail and the ground rail;
a third cell that couples the negative supply rail and the positive supply rail; and
a fourth cell that couples the positive supply rail, the ground rail, and the negative supply rail.
9. The IC device of claim 8 , wherein at least one of the first, second, third, and fourth cells includes at least one of a diode or a clamp.
10. The IC device of claim 1 , wherein the circuit block is an input/output circuit block.
11. A power clamp, comprising:
an inverter; and
a nmos transistor, wherein a gate of the nmos transistor is coupled to an output of the inverter, wherein the nmos transistor is formed in an isolated p-well, and wherein a bulk of the nmos transistor is configured to be electrically coupled to a negative supply rail.
12. The power clamp of claim 11 , wherein the inverter comprises a pmos transistor and a nmos transistor, wherein the nmos transistor of the inverter is formed in an isolated p-well.
13. The power clamp of claim 11 , wherein the nmos transistor is a part of a group of four cascoded nmos transistors that are formed in an isolated p-well.
14. The power clamp of claim 11 , further comprising:
a resistor-capacitor (RC) circuit configured to hold an input of the inverter such that an output of the inverter is sufficient turn on the nmos transistor.
15. The power clamp of claim 14 , wherein the RC circuit comprises a nmos transistor that operates as a capacitor, wherein the nmos transistor of the RC circuit is formed in an isolated p-well.
16. The power clamp of claim 14 , wherein the RC circuit comprises a capacitor.
17. The power clamp of claim 16 , wherein the capacitor is a metal capacitor.
18. An integrated circuit (IC) device, comprising:
a ground rail;
a positive supply rail;
a means for providing a negative supply voltage;
a circuit block;
a plurality of contact pads, wherein each of the ground rail, positive supply rail, means for providing a negative supply voltage, and the circuit block are coupled to a respective contact pad of the plurality of contact pads, wherein the contact pad coupled to the circuit block is configured to swing from the negative supply voltage to a voltage of the positive rail; and
means for coupling each contact pad of the plurality of contact pads to all other contact pads of the plurality of contact pads, whereby an electrostatic discharge (ESD) event between two contact pads of the plurality of contact pads can be dissipated.
19. The IC device of claim 18 , wherein the ground rail, the positive supply rail, the means for providing a negative supply voltage, and the circuit block are part of a first segment of the IC device, wherein the IC device further comprises a second segment, the second segment comprising:
a second ground rail;
a second positive supply rail;
a second circuit block;
wherein each of the second ground rail, second positive supply rail, and the second circuit block are coupled to a respective contact of the plurality of contact pads.
20. The IC device of claim 18 , wherein the circuit block is an input/output circuit block.