Electro-static discharge (ESD) damage self-test

Patent metadata

Field	Value
Publication number	US-11177654-B1
Application number	US-201816152011-A
Country	US
Kind code	B1
Filing date	Oct 4, 2018
Priority date	Oct 4, 2018
Publication date	Nov 16, 2021
Grant date	Nov 16, 2021

Abstract

Examples described herein provide a circuit and methods for self-testing to detect damage to a device, which damage may be caused by an Electro-Static Discharge (ESD) event. In an example, an integrated circuit includes an input/output circuit, an ESD protection circuit, and a system monitor. The input/output circuit has an input/output node. The ESD protection circuit is connected to the input/output node. The system monitor has a driving/measurement node selectively connectable to the input/output node. The system monitor is configured to drive and measure a voltage of the driving/measurement node. The system monitor is further configured to determine, based on driving and measuring the voltage of the driving/measurement node, whether a damaged device is present. The damaged device is in the input/output circuit or the ESD protection circuit.

First claim

What is claimed is:

1. An integrated circuit comprising:
an input/output circuit having an input/output node;
an Electro-Static Discharge (ESD) protection circuit connected to the input/output node; and
a system monitor having a driving/measurement node selectively connectable via a switch to the input/output node, the system monitor being configured to drive and measure a voltage of the driving/measurement node, the system monitor further being configured to determine, based on driving and measuring the voltage of the driving/measurement node, whether a damaged device is present, the damaged device being in the input/output circuit or the ESD protection circuit.

2. The integrated circuit of claim 1 , wherein the system monitor comprises a driver and an analog-to-digital converter (ADC), the driver being connected to the driving/measurement node and operable to drive the voltage, the ADC being connected to the driving/measurement node and operable to measure the voltage.

3. The integrated circuit of claim 1 wherein the switch is connected between the input/output node and the driving/measurement node, the system monitor being operable to control the switch to be in an open state or a closed state, the switch being operable to selectively connect the driving/measurement node to the input/output node.

4. The integrated circuit of claim 1 , wherein the system monitor is operable to:
when the driving/measurement node is connected to the input/output node:
drive the input/output node to a drive voltage;
terminate driving the input/output node; and
after a pre-determined amount of time has elapsed from terminating driving the input/output node, measure a measured voltage of the input/output node; and

determine whether a difference between an earlier voltage of the input/output node and the measured voltage indicates whether the damaged device is present.

5. The integrated circuit of claim 4 , wherein the earlier voltage is the drive voltage, the system monitor being operable to measure the drive voltage of the input/output node while driving the input/output node.

6. The integrated circuit of claim 4 , wherein:
the damaged device is indicated as present when a magnitude of the difference exceeds a specification; and
the damaged device is indicated as not being present when the magnitude of the difference does not exceed the specification.

7. The integrated circuit of claim 1 , wherein the system monitor is operable to:
while driving the voltage of the driving/measurement node:
measure a first measured voltage of the driving/measurement node when the driving/measurement node is not connected to the input/output node;
connect the driving/measurement node to the input/output node; and
measure a second measured voltage of the driving/measurement node when the driving/measurement node is connected to the input/output node; and

determine whether a difference between the first measured voltage and the second measured voltage indicates whether the damaged device is present.

8. A method of operating an integrated circuit, the method comprising:
selectively connecting, using a switch, a driving/measurement node of a system monitor to an input/output node of an input/output circuit, an Electro-Static Discharge (ESD) protection circuit being connected to the input/output node;
driving, using the system monitor, a voltage of the driving/measurement node, at least some of the driving being performed while the driving/measurement node is connected to the input/output node;
determining, using the system monitor, a voltage difference between measured voltages of the driving/measurement node, the voltage difference being at least partially in response to driving the voltage of the driving/measurement node;
determining, using the system monitor, whether the voltage difference indicates a presence of a damaged device, wherein the damaged device is in the input/output circuit or the ESD protection circuit; and
storing in memory, using the system monitor, a result corresponding to whether the voltage difference indicates the presence of the damaged device.

9. The method of claim 8 further comprising outputting the result to a user device.

10. The method of claim 8 further comprising setting the input/output circuit to a high-impedance state.

11. The method of claim 8 , wherein the switch is controlled by the system monitor.

12. The method of claim 8 , wherein the system monitor comprises:
a driver, wherein the driver is used to charge the driving/measurement node; and
an analog-to-digital converter (ADC), wherein the ADC is used to measure the measured voltages of the driving/measurement node.

13. The method of claim 8 , wherein:
determining the voltage difference between the measured voltages of the driving/measurement node includes:
driving the voltage of the driving/measurement node when the driving/measurement node is connected to the input/output node;
terminating driving the voltage of the driving/measurement node; and
after a pre-determined amount of time has elapsed from terminating driving the voltage of the driving/measurement node, measuring a subsequent measured voltage of the driving/measurement node when the driving/measurement node is connected to the input/output node, wherein the voltage difference is between an earlier measured voltage of the driving/measurement node and the subsequent measured voltage; and

determining whether the voltage difference indicates the presence of the damaged device includes comparing the voltage difference to a specification, wherein the presence of the damaged device is indicated when a magnitude of the voltage difference exceeds the specification.

14. The method of claim 13 , wherein determining the voltage difference between the measured voltages of the driving/measurement node includes:
measuring the earlier measured voltage of the driving/measurement node when driving the voltage of the driving/measurement node and the driving/measurement node is connected to the input/output node.

15. The method of claim 8 , wherein:
determining the voltage difference between the measured voltages of the driving/measurement node includes:
driving the voltage of the driving/measurement node when the driving/measurement node is not connected to the input/output node;
measuring a first measured voltage of the driving/measurement node when the driving/measurement node is not connected to the input/output node and while driving the voltage of the driving/measurement node; and
measuring a second measured voltage of the driving/measurement node when the driving/measurement node is connected to the input/output node and while driving the voltage of the driving/measurement node, wherein the voltage difference is between the first measured voltage and the second measured voltage; and

determining whether the voltage difference indicates the presence of the damaged device includes comparing the voltage difference to a specification, wherein the presence of the damaged device is indicated when a magnitude of the voltage difference exceeds the specification.

16. An integrated circuit comprising:
an input/output circuit having an input/output node;
an Electro-Static Discharge (ESD) protection circuit connected to the input/output node; and
a system monitor having a driving/measurement node selectively connectable via a switch to the input/output node, the system monitor comprising:
a driver configured to drive a voltage of the driving/measurement node;
an analog-to-digital converter (ADC) configured to obtain measurement data relating to the driv

Assignees

• Xilinx Inc

Inventors

• Jennings John K
• Karp James
• Hart Michael J

Classifications

• H10D89/60

  Integrated devices comprising arrangements for electrical or thermal protection, e.g. protection circuits against electrostatic discharge [ESD] · CPC title

• H10D89/811

  using FETs as protective elements · CPC title

• H02H9/046 Primary

  responsive to excess voltage appearing at terminals of integrated circuits · CPC title

• H02H9/042 Primary

  comprising means to limit the absorbed power or indicate damaged over-voltage protection device · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title