Testable integrated circuit and test method

Abstract

An integrated circuit (100) is disclosed comprising a plurality of circuit portions (130), each of the circuit portions having an internal supply rail (170) coupled to a global supply rail (160) via acluster (140) of switches (152; 154) coupled in parallel between the internal supply rail (170) and the global supply rail (160). Each cluster (140) of switches (152; 154) has a first switch (152) having a first size and a second switch (154) having a second size, a fault-free first switch (152) having a higher resistance than a fault-free second switch (154). The IC (100) further comprises a test arrangement for testing the respective clusters (140) of switches (152; 154) in a test mode. The test arrangement comprises a test control input; a test output coupled to the respective internal supply rails (170) and control means (110, 114, 116) coupled to the test control input for enabling a selected cluster (140) of switches (152; 154) in the test mode. The control means comprise first selection means (114) for selectively enabling the first switch (152) and second selection means (116) for selectively enabling the second switch (154) of the selected cluster (140) in the test mode. Thisarrangement allows for the accurate measurement of the resistance of power switches (152; 154) between a global power rail (160) and an internal power rail (170) of a circuit portion (130), thus facilitating the detection of both resistive and stuck-at faults in these switches (152; 154).

Description

technical field [0001] The present invention relates to an integrated circuit (IC) comprising a plurality of circuit portions each having an internal supply rail coupled to a global supply rail via a switch bank connected in parallel between the internal supply rail and the global supply rail coupled, and the supply input is coupled to the global supply rail. [0002] The invention also relates to methods for testing such ICs. Background technique [0003] Continuing advances in IC design and production have led to the fabrication of very large-scale integrated (VLSI) ICs that can perform many different functions and include millions of devices (eg, transistors), which can be organized into distinct circuit segments , each circuit part implements at least a part of IC-specific functions. Such ICs tend to dissipate a considerable amount of power, which can cause many problems. For example, at peak consumption, the power demands of various circuit parts may exceed the capab...

AI Technical Summary

Problems solved by technology

[0006] The disadvantage of this approach is that the on-chip comparators are not capable of the required level of accuracy to detect specific resistive defects in such switches

Furthermore, this method does not take into account that the switch group has a first switch with a first size and a second switch with a second size, and that a defect-free first switch has a higher resistance than a defect-free second switch

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