SYSTEM AND METHOD FOR DETECTING DEFECTS WITHIN AN ELECTRICAL CIRCUIT BY ANALYZING QUIESCENT CURRENT
First Claim
1. A system for detecting defects within circuits, the system comprising:
- a circuit;
a power supply unit, said power supply unit configured to transmit supply current to said circuit;
a current meter configured to receive said supply current and to transmit a first signal and a second signal respectively indicating a first value and a second value of said supply current; and
an analyzer configured to receive said first and second signals, to determine a threshold value based on said first signal, to compare said second signal to said threshold value, and to determine whether said circuit is defective based on a comparison of said second signal to said threshold value.
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Accused Products
Abstract
The present invention, in general, provides for a testing system and method for detecting defects within a circuit. A current signature of the quiescent current of the circuit is determined, and certain constant values are calculated based on the current signature using a linear iterative regression. A defect free state for the circuit associated with a minimum quiescent current (IDDQ) is then determined. The IDDQ of the circuit for this state is measured, and a signal indicating the IDDQ at this state is used along with the aforementioned constant values to create upper and lower threshold values. Thereafter, signals indicating the value of IDDQ for a plurality of other states are compared to the upper and lower threshold values. The circuit is determined to be defective if the values of any of the signals is greater than the upper threshold value or is less than the lower threshold value.
20 Citations
20 Claims
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1. A system for detecting defects within circuits, the system comprising:
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a circuit;
a power supply unit, said power supply unit configured to transmit supply current to said circuit;
a current meter configured to receive said supply current and to transmit a first signal and a second signal respectively indicating a first value and a second value of said supply current; and
an analyzer configured to receive said first and second signals, to determine a threshold value based on said first signal, to compare said second signal to said threshold value, and to determine whether said circuit is defective based on a comparison of said second signal to said threshold value. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for detecting defects within circuits, the method comprising the steps of:
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providing a circuit;
measuring a value of a supply current associated with said circuit when said circuit is in a first state;
determining a threshold value based on said value of said supply current measured in said measuring step;
receiving a signal indicating another value of said supply current when said circuit is in a second state;
comparing said signal to said threshold value; and
detecting a defect in said circuit based on said comparing step. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for detecting defects within circuits, the method comprising the steps of:
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providing a plurality of circuits;
producing signals indicating values of supply currents associated with said circuits;
analyzing values of said signals;
determining a constant value based on said analyzing step;
selecting a circuit;
placing said circuit into a first state subsequent to said determining step;
producing a first signal indicating a first value of a supply current of said circuit when said circuit is in said first state;
determining a threshold value based on said constant value and said first signal;
placing said first circuit into another state;
producing a second signal indicating a second value of said supply current when said circuit is in said other state; and
determining whether a value of said second signal exceeds said first threshold value. - View Dependent Claims (19, 20)
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Specification