Clock controller for at-speed testing of scan circuits

摘要

A test clock controller for generating a test clock signal for scan chains in integrated circuits having one or more clock domains, comprises a shift clock controller for generating a shift clock signal for use in loading test patterns into scan chains in the clock domains and for unloading a test response patterns from the scan chains and for generating a burst phase signal after loading a test pattern; and a burst clock controller associated with each of one or more clock domains and responsive to a burst phase signal for generating a burst of clock pulses derived from a respective reference clocks and including a first group of burst clock pulses having a selected reduced frequency relative to the reference clock and a second group of burst clock pulses having a frequency corresponding to that of the reference clock.