Hierarchical test generation for analog circuits using incremental test development

In this paper, we propose an efficient test generation scheme for analog circuits consisting of embedded modules. The proposed scheme simplifies the test generation effort by incrementally generating tests for the individual embedded modules rather than for the full circuit. At each step of the test generation process, the test waveform is incrementally optimized. As input nodes to an embedded module are not directly accessible, the test optimization considers only those waveforms that can be justified from an embedded module input to a primary input of the circuit-under-test using a signal backtrace procedure. The "best" selected test is then evaluated at the full circuit level for controllability of the test stimulus and observability of the test results. In this manner, repeated evaluation of the full circuit over the search space of all test stimuli is not necessary and the complexity of test search can be reduced.