Dual mode programmable delay element

Abstract

Rapid set-up is achieved in a programmable delay element having identical pairs of positionally corresponding delay stages in parallel arrays. The pairs of delay elements include identical arrangements of circuit elements and are replicable in a step-and-repeat fashion to simplify delay element manufacture for any arbitrary maximum delay time to be provided. Delay stages of the delay element are comprised of multiplexers. Outputs of respective delay stages are simultaneously stored as a signal transition is propagated through the delay stages in a first order to program the delay element. Thereafter, signals are propagated through selected delay stages in a second order controlled by the simultaneously stored outputs of respective delay stages during the propagation of the signal transition. The selected stages through which a signal is propagated in the second order are the same stages through which the signal transition had propagated in the first order at the time the delay stage outputs were simultaneously stored.