Scan cell for an integrated circuit
AssigneeFreescale Semiconductor, Inc.
InventorsChetan Verma, Gulshan Miglani
Life of this patent
Estimating the term…
Abstract
A scan cell and a method for detecting supply voltage degradation in an integrated circuit using the scan cell. The scan cell includes a voltage comparator and a scan flip-flop. The voltage comparator compares a supply voltage with a reference voltage to generate a comparator output signal. The scan flip-flop is coupled to the voltage comparator, and receives the comparator output signal. Use of the scan cell for detecting IR drop replaces expensive methods like FIB (Focused Ion Beam) and EBEAM (electron beam).
Claims15
A scan cell for detecting supply voltage degradation in an integrated circuit, the integrated circuit including a power grid having a plurality of power rails that carry a supply voltage, the scan cell comprising:
- a voltage comparator that compares the supply voltage carried by a selected one of the power rails from amongst the plurality of power rails with a reference voltage and generates a comparator output signal, wherein the reference voltage is based on a predetermined threshold voltage drop of the integrated circuit;
- and
- a scan flip-flop coupled to the voltage comparator that receives the comparator output signal.
An integrated circuit including a plurality of scan cells each of which detects supply voltage degradation in the integrated circuit, and a power grid having a plurality of power rails that carry a supply voltage, each scan cell comprising:
- a voltage comparator that compares the supply voltage carried by a selected one of the power rails from amongst the plurality of power rails with a reference voltage and generates a comparator output signal, wherein the reference voltage is based on a predetermined threshold voltage drop in the integrated circuit;
- and
- a scan flip-flop coupled to the voltage comparator that receives the comparator output signal.
A method for detecting supply voltage degradation in an integrated circuit, the integrated circuit including a power grid having a plurality of power rails that carry a supply voltage, the method comprising:
- comparing the supply voltage carried by at least one of the power rails from amongst the plurality of power rails with a reference voltage to generate a comparator output signal, wherein the reference voltage is based on a predetermined threshold voltage drop in the integrated circuit;
- and
- providing the comparator output signal to a scannable latch circuit.
Dependencies are inferred from the claim text.