Multiple stage fuse circuitry for counting failure events
The disclosure relates in some aspects to an apparatus that includes stages of a failure event counting circuit including an N th stage where N refers to an arbitrary stage of the stages of the failure event counting circuit. The N th stage may include an N th fuse trigger circuit configured to receive an event detector signal indicative of a failure event, an N th electronic fuse configured to disconnect a circuit path between a voltage source and a ground in response to the event detector signal, and an N th delay circuit coupled to the N th e-fuse and configured to cause a time delay for activating a subsequent stage of the failure event counting circuit in response to the N th e-fuse disconnecting. In this aspect, each of the stages of the failure event counting circuit may be configured to use the respective e-fuse to record a discrete failure event.
1. An apparatus, comprising:
a plurality of stages of a failure event counting circuit comprising an N th stage where N refers to an arbitrary stage of the plurality of stages of the failure event counting circuit, the N th stage comprising:
an N th fuse trigger circuit configured to receive an event detector signal indicative of a failure event;
an N th electronic fuse (e-fuse) configured to disconnect a circuit path between a voltage source and a ground in response to the event detector signal; and
an N th delay circuit coupled to the N th e-fuse and configured to cause a time delay for activating a subsequent stage of the failure event counting circuit in response to the N th e-fuse disconnecting,
wherein each of the stages of the failure event counting circuit is configured to use the respective e-fuse to record a discrete failure event.
2. The apparatus of claim 1 , wherein the N th fuse trigger circuit is further configured to receive an N th stage activation signal for activating the N th stage,
wherein the N th fuse trigger circuit is configured to allow a fusing current to flow to the N th e-fuse in response to the event detector signal and the N th stage activation signal, and
wherein the N th delay circuit is configured to cause the time delay to generate a subsequent stage activation signal for activating the subsequent stage after the time delay in response to the N th e-fuse disconnecting.
3. The apparatus of claim 1 , further comprising:
a final stage of the failure event counting circuit connected to a last stage of the plurality of stages of the failure event counting circuit, the final stage comprising:
a final fuse trigger circuit to receive a final event detector signal indicative of a final failure event, and
a final e-fuse configured to disconnect in response to the final event detector signal.
4. The apparatus of claim 3 , wherein the final fuse trigger circuit is further configured to receive, from the last stage, a final stage activation signal for activating the final stage, and
wherein the final fuse trigger circuit is configured to allow a fusing current to flow to the final e-fuse in response to the final event detector signal and the final stage activation signal.
5. The apparatus of claim 1 , wherein the time delay applied by the N th delay circuit is associated with a type of the failure event, the type of the failure event characterizing at least one of a shape of the event detector signal or a magnitude of the event detector signal.
6. The apparatus of claim 5 , wherein the time delay is greater than a pulse duration of the event.
7. The apparatus of claim 1 , wherein the time delay is greater than a time it takes to disconnect the N th e-fuse.
8. The apparatus of claim 1 , wherein the N th delay circuit comprises a resistor and a capacitor arranged in series, and
wherein an input into the N th delay circuit is connected to the resistor at a node not shared with the capacitor, and an output from the N th delay circuit is connected to a common node shared by the resistor and the capacitor.
9. The apparatus of claim 1 , further comprising:
a counter circuit configured to generate a count of a number of e-fuses from the plurality of stages that have disconnected in response to one or more failure events,
wherein an output node of the N th delay circuit from the N th stage is connected to the counter circuit to indicate to the counter circuit that the N th e-fuse has disconnected.
10. The apparatus of claim 9 , wherein the counter circuit comprises at least one of a scan chain circuit or a status register circuit.
11. The apparatus of claim 1 , wherein an N th stage of the plurality of stages of the failure event counting circuit further comprises:
an N th light emitting circuit connected to the N th e-fuse and configured to illuminate in response to the N th e-fuse disconnecting.
12. The apparatus of claim 1 , wherein the N th fuse trigger circuit comprises at least one of a NAND gate configured to receive the event detector signal or a NOR gate configured to receive the event detector signal.
13. The apparatus of claim 1 , wherein the time delay applied by the N th delay circuit is adjustable.
14. The apparatus of claim 1 , wherein the apparatus further comprises:
a latch circuit including a set/reset (SR) latch and connected to the N th fuse trigger circuit to prevent the event detector signal from entering the subsequent stage of the plurality of stages.
15. The apparatus of claim 1 , further comprising:
a voltage capture circuit configured to detect a maximum voltage magnitude during each failure event;
a decoder circuit configured to convert a count of a number of disconnected e-fuses in the plurality stages to an apparatus voltage magnitude; and
a magnitude comparison circuit configured to:
compare the detected maximum voltage magnitude and the apparatus voltage magnitude based on the number of disconnected e-fuses,
output a first signal as the event detector signal to the plurality of stages in response to the detected maximum voltage magnitude exceeding the apparatus voltage magnitude to cause an e-fuse of one of the plurality of stages to disconnect, and
output a second signal, different from the first signal, as the event detector signal to the plurality of stages in response to the detected maximum voltage magnitude being less than or equal to the apparatus voltage magnitude.
16. The apparatus of claim 1 , further comprising:
a voltage capture circuit configured to detect a maximum voltage magnitude during each failure event;
a converter circuit configured to convert the detected maximum voltage magnitude to a maximum digital magnitude value; and
a digital value comparison circuit configured to:
compare an apparatus digital value based on a count of a number of disconnected e-fuses from the plurality of stages and the maximum digital magnitude value,
output a first signal as the event detector signal to the plurality of stages in response to a current digital magnitude value exceeding the apparatus digital value to cause an e-fuse of one of the plurality of stages to disconnect, and
output a second signal, different from the first signal, as the event detector signal to the plurality of stages in response to the current digital magnitude value being less than or equal to the apparatus digital value.
17. The apparatus of claim 1 , wherein the N th fuse trigger circuit, the N th e-fuse, and the N th delay circuit are connected to one another.
18. An apparatus, comprising:
a plurality of stages of a failure event counting circuit comprising an N th stage where N refers to an arbitrary stage of the plurality of stages of the failure event counting circuit, the N th stage comprising:
an N th fuse trigger circuit configured to receive an event detector signal indicative of a failure event;
an N th electronic fuse (e-fuse) configured to disconnect a circuit path between a voltage source and a ground in response to the event detector signal; and
an N th delay circuit coupled to the N th e-fuse and configured to cause a time delay for activating a subsequent stage of the failure event counting circuit in response to the N th e-fuse disconnecting,
wherein each of the stages of the failure event counting circuit is configured to use the respective e-fuse to record a discrete failure event; and
a final stage of the failure event counting circuit connected to a last stage of the plurality of stages of the failure event counting circuit, the final stage comprising:
a final fuse trigger circuit to receive a final event detector signal indicative of a final failure event, and
a final e-fuse configured to disconnect in response to the final event detector signal.
19. The apparatus of claim 18 , wherein the N th fuse trigger circuit is further configured to receive an N th stage activation signal for activating the N th stage,
wherein the N th fuse trigger circuit is configured to allow a fusing current to flow to the N th e-fuse in response to the event detector signal and the N th stage activation signal, and
wherein the N th delay circuit is configured to cause the time delay to generate a subsequent stage activation signal for activating the subsequent stage after the time delay in response to the N th e-fuse disconnecting.