Variable delay line using two blender delays

Abstract

A variable delay line comprises a first blender delay configured to provide a first signal, a second blender delay configured to provide a second signal complementary to the first signal, and a coarsedelay configured to delay the first signal if an even number of coarse delay elements are selected and delay the second signal if an odd number of coarse delay elements are selected.

Description

Background technique [0001] Variable delay lines are used in many different types of circuits, such as delay-locked loops (DLLs), to delay signals. A variable delay line typically consists of a mixer delay and a coarse delay. A coarse delay typically consists of a series of coarse delay elements or cells, each delaying the input signal by an equal amount. By choosing the number of coarse delay elements used, the coarse delay value can be obtained. Mixer delays typically provide delays between zero and the delay of one coarse delay element. The Mixer Delay and Coarse Delay of the Variable Delay Line combine to provide the desired total delay based on the control signal input. [0002] One disadvantage of combining mixer and coarse delays is that the mixer delay shifts from its minimum delay to its maximum delay, or from its maximum delay to its minimum delay, at the point where the coarse delay is incremented or decremented by a coarse delay element . Mixer Delay and Coars...

AI Technical Summary

Problems solved by technology

[0002] One disadvantage of combining mixer delays and coarse delays is that the mixer delay shifts from its minimum delay to its maximum delay, or from its maximum delay to its minimum delay, at the point where the coarse delay is incremented or decremented by a coarse delay element

Often, the solution to the synchronization problem is to use multiple delay lines or a large multiplexer circuit, but both of these solutions increase layout space requirements, current consumption, and expense

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