Counter-controlled delay line
AssigneeXilinx, Inc.
InventorAlireza S. Kaviani
Life of this patent
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Abstract
A counter-controlled delay line for delaying signals having a wide range of possible frequencies is described. The counter-controlled delay line receives an input clock and produces a delayed output clock based on a delay select control signal. The delay select control signal includes three granularities of delay: a coarse grain, medium grain, and fine grain. The coarse grain delay is provided by a counter. The medium grain delay is provided by a sequential starter circuit coupled to an oscillator. The fine grain delay is provided by a trim unit.
Claims36
An integrated circuit comprising:
- at least one edge delay unit for delaying edges of an input signal and providing delayed edge pulses, the edge delay unit comprising:
- an oscillator to generate a main clock, the oscillator having an adjustable start point providing a medium grain delay adjustment to the input signal;
- and
- a counter for counting edges of the main clock, the counter providing a coarse grain delay adjustment to the input signal.
An edge delay unit comprising:
- an oscillator for providing a main clock, the oscillator having a selectable starting point applying a medium grain delay adjustment to an input signal;
- a counter coupled to the oscillator for counting edges of the main clock, the counter applying a coarse grain delay adjustment to the input signal;
- and
- a sequential starter circuit coupled to the oscillator for detecting an edge of the input signal and selecting the starting point of the oscillator.
A circuit for delaying an input signal comprising:
- means for providing a delay adjustment value including a coarse grain value and a medium grain value;
- means for starting an oscillator to produce a main clock signal responsive to an edge of the input signal and the medium grain value;
- means for counting edges of the main clock signal;
- means for comparing counted edges of the main clock signal to a predetermined maximum count value corresponding to the coarse grain value;
- and
- means for generating an edge pulse when the counted edges matches the predetermined maximum count value.
Dependencies are inferred from the claim text.