Clock Duty-Cycle Correction Using Delay-Matched Distribution
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Solution Overview
Problem
Existing clock signal distribution networks face challenges in maintaining the duty-cycle of clock signals, leading to distortion due to process-induced variations, which can reduce integrated circuit performance and cause functional issues.
Innovation Solution
A duty-cycle correction circuit is introduced, utilizing a global clock tree and differential-to-single-ended clock drivers with adjustable characteristics to generate and distribute duty-cycle corrected clock signals, compensating for phase differences and process-induced distortions through adjustable delays and drive strengths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If differential clock paths are used to distribute clock signals, then duty-cycle distortion is reduced, but power consumption increases significantly and space requirements increase
Solution Approach 1:
A duty-cycle correction circuit is introduced as an intermediary component in the clock distribution network. This circuit receives the distorted clock signal, corrects its duty cycle using adjustable delay elements, and outputs a corrected clock signal. The correction circuit acts as a mediator between the clock source and the load, eliminating the need for complex differential paths while maintaining signal quality.
Solution Approach 2:
The invention adjusts the delay parameters of clock signals through programmable delay elements within the correction circuit. By dynamically changing the delay parameters, the circuit compensates for process-induced distortions and maintains the desired duty cycle. This parameter adjustment approach allows flexible adaptation to different process variations without requiring hardware redesign.
2Manufacturing precision
If differential clock paths are used to distribute clock signals, then duty-cycle distortion is reduced, but the space required for the clock distribution network increases
Solution Approach 1:
The duty-cycle correction circuit serves as a compact intermediary that consolidates the function of complex differential paths into a single integrated block. This mediator approach reduces the overall clock distribution network area by replacing extensive parallel differential routing with a centralized correction unit that can be strategically placed in the chip layout.
Solution Approach 2:
The invention merges multiple clock path functions into a single correction circuit that handles both clock phases. Instead of maintaining separate differential paths for each clock signal, the correction circuit combines the functionality into one unit that processes and corrects both phases, thereby reducing the total area required for clock distribution.
3Use of energy by moving object
If single-ended clock signals are distributed, then power consumption and space requirements are reduced, but duty-cycle distortion increases due to process-induced variations
Solution Approach 1:
The duty-cycle correction circuit incorporates feedback mechanisms that monitor the actual duty cycle of the distributed clock signal and adjust the delay parameters accordingly. This feedback loop compensates for process-induced variations by dynamically correcting the duty cycle, ensuring that single-ended distribution does not sacrifice signal quality.
Solution Approach 2:
The invention introduces dynamic adjustability to the clock distribution system through programmable delay elements. These dynamic components allow the system to adapt to process variations by adjusting delay parameters in real-time, transforming a static single-ended distribution network into a dynamically correctable system that maintains duty-cycle precision.
Data Source
AI summary
Duty-cycle correction circuits, clock distribution networks, and methods for correcting duty-cycle distortion are disclosed, including methods and apparatus for correcting duty-cycle distortion of differential output clock signals provided from a clock distribution network. In one such method, a single-ended clock signal is generated from differential input clock signals for distribution over a clock distribution network and from which the differential output clock signals are generated. A delay of a model delay path is matched to a propagation delay of the clock distribution network, and the single ended clock signal is adjusted to compensate for duty-cycle distortion.