On reducing test data volume and test application time for multiple scan chain designs

We propose a new method for reducing test data volume and test application time in scan designs with multiple scan chains. The method uses a reconfigurable switch to apply tests from a limited number of external inputs to a large number of internal scan chains. The reconfigurable switch allows different subsets of scan chains to be connected to the same external input at different times, thus allowing varied tests to be applied to the circuit.