US Patent 7865759 Programmable clock control architecture for at-speed testing

According to one exemplary embodiment, an N-stage programmable clock control architecture includes N flip-flops, where the N flip-flops are clocked by a primary clock source, such as a PLL. The N-stage programmable clock control architecture further includes means for programming the N flip-flops such that the N-stage programmable clock control architecture outputs N programmed at-speed clock pulses. For example, when N is equal to 3, three programmed clock pulses can be outputted by the N-stage programmable clock control architecture, with a total of eight different patterns of programmed clock pulses. The N-stage programmable clock control architecture can thus adequately test, for example, combinational logic requiring greater than two consecutive clock pulses for complete at-speed testing. In one embodiment, scan-shift registers can be utilized to program the N flip-flops. In another embodiment, a look-up table can be used to program the N flip-flops.