US 2026/0171790 A1 · SYSTEM AND METHOD TO HANDLE I/O CELL CURRENT INJECTION FAULTS

Abstract

An integrated circuit is provided with a signal node/IO pad in an output buffer that is protected by a current injection protection circuit which includes first and second comparators connected between a first voltage supply and a second voltage supply to generate first and second control signals in response to, respectively, a positive or negative injected current at the signal node, and which also includes a pre-driver stack of transistors which generate, respectively, a positive gate control signal and negative gate control signal, and which also includes a multiplex selection circuit connected to output the positive gate control signal and negative gate control signal to the output buffer to clamp signal node to a first clamped voltage if a voltage on the signal node exceeds the first supply voltage or to a second clamped voltage if a voltage on the signal node falls below the second supply voltage.

Claims20

Dependent claims

An integrated circuit, comprising:

an external signal node connected to receive an injected current;
an output buffer comprising a first output stage connected between a first voltage supply and the external signal node;
and
a current injection protection circuit comprising:
a first comparator configured to generate a first current injection control signal by comparing the first voltage supply to a first overvoltage signal generated from a voltage on the external signal node;
and
a multiplex selection circuit comprising a first input connected to receive a first gate control signal that is generated from the first current injection control signal, a second input connected to receive a first pre-driver signal, and an output connected to a control gate terminal of the output buffer which clamps the external signal node to the first supply voltage if the voltage on the external signal node passes a trip threshold of the first comparator.

4 more elements

An electronic device, comprising:

an application circuit;
a first supply rail having a first reference voltage;
a second supply rail having a second reference voltage different from the first reference voltage;
an I/O pad connected to said application circuit;
and
a protection circuit for protecting said application circuit from an injected current at the I./O pad, said protection circuit comprising:
an output driver connected and configured to drive the I/O pad towards a first reference voltage during normal operation;
one or more first pre-driver circuits connected and configured to generate first pre-driver gate control signals during normal operation;
one or more current injection detector circuits connected and configured to generate second pre-driver gate control signals in response to detecting a current injection event at the I/O pad;
and
one or more multiplexer selection circuits connected and configured to supply the first pre-driver gate control signals to the output driver during normal operation, and to supply the second pre-driver gate control signals to the output driver during normal operation,
where the output driver is connected to clamp the I/O pad voltage to a first clamped voltage within approximately one volt of the first reference voltage during the detected current injection event.

9 more elements

Dependencies are inferred from the claim text.

System and method to handle i/o cell current injection faults

Life of this patent

System and method to handle i/o cell current injection faults

Life of this patent

Abstract

Claims20