Delay-Compensated Data Multiplexing for Stable High-Speed Timing
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Solution Overview
Problem
Conventional multiplexers experience performance degradation and data corruption at high frequencies due to variable clock-to-data delays, which are sensitive to temperature, voltage, and manufacturing variations, limiting their operating frequency and reliability.
Innovation Solution
The introduction of a delay-compensator in the clock line, using a second clock signal with a fixed delay, such as a quadrature-phase clock, to establish a stable timing relationship between clock and data waveforms, thereby compensating for variable clock-to-data delays and maintaining timing margins across varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional multiplexers operate at high frequencies, then productivity increases, but reliability deteriorates due to data corruption from variable clock-to-data delays
Solution Approach 1:
The patent changes the timing parameter of the clock signal by introducing a delay element that shifts the clock edge relative to the data transitions. This parameter adjustment ensures that the clock samples data at optimal points, maintaining reliable operation at high frequencies despite variations in clock-to-data delay caused by temperature, voltage, or manufacturing variations.
Solution Approach 2:
The delay element is positioned in the clock path to preemptively adjust the clock timing before it reaches the sampling point. This preliminary timing adjustment ensures that clock edges align properly with stable data periods, preventing data corruption before it can occur during high-frequency operation.
2Reliability
If clock-to-data delay is reduced to maintain timing margins, then reliability improves, but device complexity increases due to additional delay compensation circuits
Solution Approach 1:
The patent introduces a delay element as an intermediary component in the clock path. This intermediary adjusts the timing relationship between clock and data signals, providing stable timing margins without requiring complex delay compensation circuits or multiple clock domains. The simple delay element mediates the timing conflict between clock and data transitions.
3Reliability
If delay compensation circuits are added to reduce sensitivity to variations, then reliability improves, but device complexity increases
Solution Approach 1:
Rather than adding complex compensation circuits, the patent simply changes the clock timing parameter by introducing a delay element. This parameter adjustment makes the multiplexer inherently less sensitive to variations in clock-to-data delay, temperature, voltage, and manufacturing processes, achieving improved reliability with minimal additional complexity.
Data Source
AI summary
A method and apparatus for data multiplexing is capable of high-speed operation with acceptable timing margins and has reduced sensitivity to supply voltage, temperature, manufacturing and other variations. One implementation relates to a data multiplexer that has no significant speed limitation associated with the clock-to-data delay of data latches, flip-flops, etc. In one implementation, clock-to-data delay is compensated for by introducing a delay-compensator in the clock line that drives a selector stage of the multiplexer. In one such implementation, a timing relationship is established between clock and data waveforms by timing the data waveforms with a first in-phase clock and operating the delay-compensated selector clock line with a second clock, which is delayed with respect to the first clock. The second clock can have a quadrature-phase delay with respect to the in-phase clock.