Clock Tree Duty Cycle Calibration Using DC Offset Trim Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Duty cycle distortion in clock signals used in electrical circuit devices leads to reduced timing windows and unreliable performance, especially at high input/output speeds, due to sources like amplifiers and parasitic conductor capacitance, which existing solutions like DLL circuits fail to adequately address due to power consumption and complexity.
Innovation Solution
Incorporating clock distortion calibration circuitry on semiconductor dies to compare and adjust the duty cycles of differential clock signals, using trim values and biasing to calibrate the signals and mitigate distortion, thereby accounting for die-to-die variations and reducing area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If duty cycle distortion calibration is implemented using traditional DLL circuits, then timing margin distortion can be corrected, but power consumption increases and device complexity increases
Solution Approach 1:
The patent extracts only the essential calibration function from the complete DLL circuit, implementing a standalone calibration circuit that measures and corrects duty cycle distortion without requiring the full DLL infrastructure. This selective extraction reduces power consumption while maintaining the core correction capability.
Solution Approach 2:
The calibration circuit is designed to work with various clock signal types (single-ended and differential) and can be integrated into different electrical circuit configurations. This universal approach allows the same calibration mechanism to serve multiple purposes across different circuit designs, reducing overall system complexity.
2Manufacturing precision
If traditional DLL circuits are used for duty cycle calibration, then timing distortion can be mitigated, but device complexity increases
Solution Approach 1:
The patent separates the calibration function from the main clock distribution network, creating an independent calibration circuit that can operate autonomously. This extraction eliminates the need for complex DLL control logic, phase detectors, and charge pumps, significantly reducing device complexity while preserving calibration effectiveness.
Solution Approach 2:
The calibration circuit automatically measures its own clock signal characteristics and adjusts its internal components to correct duty cycle distortion without external control. This self-service capability eliminates the need for complex external control logic and reduces overall system complexity.
3Manufacturing precision
If calibration is performed at distant clock tree locations, then distortion can be corrected, but timing windows are reduced due to propagation delays
Solution Approach 1:
The patent places calibration circuits at multiple distributed locations throughout the clock tree, allowing each circuit to correct distortion locally for its specific region. This local calibration approach eliminates the need for long-distance signal propagation and associated delays, preserving timing windows while achieving comprehensive distortion correction.
Solution Approach 2:
The clock distribution network is divided into multiple segments, each with its own calibration circuit. This segmentation allows independent calibration of each segment, reducing the impact of propagation delays and enabling precise local correction without affecting the entire clock tree.
4Productivity
If high input/output speeds are used, then data transfer rate increases, but duty cycle distortion becomes more challenging to reduce
Solution Approach 1:
The calibration circuit incorporates adjustable parameters that can be dynamically tuned based on operating conditions. As input/output speeds increase, the calibration circuit automatically adjusts its correction parameters to compensate for the increased susceptibility to distortion, maintaining precision across a wide range of data transfer rates.
Solution Approach 2:
The patent implements variable calibration parameters that can be modified based on the operating frequency and observed distortion levels. At higher data transfer rates, the calibration circuit changes its correction parameters to account for reduced timing margins and increased distortion effects, enabling effective calibration across different speed regimes.
Data Source
AI summary
Several embodiments of electrical circuit devices and systems with clock distortion calibration circuitry are disclosed herein. In one embodiment, an electrical circuit device includes an electrical circuit die having clock distortion calibration circuitry to calibrate a clock signal. The clock distortion calibration circuitry is configured to compare a first duty cycle of a first voltage signal of the clock signal to a second duty cycle of a second voltage signal of the clock signal. Based on the comparison, the clock calibration circuitry is configured to adjust a trim value associated with at least one of the first and the second duty cycles of the first and the second voltage signals, respectively, to calibrate at least one of the first and the second duty cycles and account for duty cycle distortion encountered as the clock signal propagates through a clock tree of the electrical circuit device.