Automatic signal delay adjustment method
AssigneeBurroughs Corporation
InventorsLaurence P. Flora, Michael A. McCullough
Life of this patent
Estimating the term…
Abstract
A method for automatically adjusting the propagation time delay of an electrical circuit, such as an integrated circuit chip. In a preferred embodiment, the method is employed to de-skew the clock outputs provided by a plurality of clock distribution chips having different signal propagation times. In a preferred implementation of the method, feedback circuitry including a multi-tapped delay line and an accurate constant delay are employed in conjunction with a phase comparator for automatically adjusting the propagation delay of each chip to provide substantially the same constant delay relative to a main system clock for the clock outputs provided by the clock distribution chips.
Claims15
A method for automatically providing a desired propagation delay between an input signal and an output signal produced by an electrical circuit in response thereto, said method comprising the steps of:
- producing in response to said input signal a plurality of delayed signals having different delays relative to said input signal;
- selecting one of said delayed signals for application to said circuit;
- comparing the time relationship between a first signal derived from said output signal and a second signal derived from said input signal for determining whether the propagation delay provided by a selected delayed signal is substantially equal to said desired propagation delay;
- automatically selecting a different delayed signal if the propagation delay provided by a currently selected delayed signal is determined not to be substantially equal to said desired propagation delay;
- repeating the steps of comparing and automatically selecting until a currently selected delayed signal is determined to provide substantially said desired propagation delay;
- and
- preventing selection of a different delayed signal when the currently selected delayed signal is determined to provide a propagation delay which is substantially equal to said desired propagation delay.
Dependencies are inferred from the claim text.