Differential Clock Duty Calibration for Clock Tree Distortion
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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 amplifiers and parasitic conductor capacitance, which existing solutions like DLL circuits fail to adequately address due to power consumption and complexity.
Innovation Solution
The implementation of clock distortion calibration circuitry on semiconductor dies that compares and adjusts the duty cycles of differential clock signals, using trim values and biasing to calibrate the clock signal at points closer to electrical circuits, accounting for die-to-die variations and reducing distortion without requiring a warm-up cycle or excessive power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If DLL circuits are used to calibrate clock signals, then duty cycle distortion is reduced, but power consumption increases and device complexity increases
Solution Approach 1:
The patent extracts the essential calibration function from complex DLL circuits by using only the core components (buffers and trim circuits) needed for duty cycle adjustment, eliminating unnecessary complexity and power consumption while maintaining calibration effectiveness
Solution Approach 2:
The invention uses simple, low-power buffer circuits and trim circuits instead of expensive, high-power DLL circuits, accepting that the calibration is performed once during manufacturing rather than requiring continuous active calibration
2Manufacturing precision
If DLL circuits are used to calibrate clock signals, then duty cycle distortion is reduced, but device complexity increases
Solution Approach 1:
The patent extracts the essential calibration function from complex DLL circuits by using only the core components (buffers and trim circuits) needed for duty cycle adjustment, eliminating unnecessary complexity while maintaining calibration effectiveness
Solution Approach 2:
Instead of using complex DLL circuits to actively adjust clock signals throughout operation, the patent inverts the approach by using simple trim circuits to pre-adjust buffer characteristics during manufacturing, achieving calibration without ongoing complexity
3Adaptability or versatility
If clock signals are transmitted over long distances through amplifiers, then electrical circuits can be positioned flexibly, but duty cycle distortion increases
Solution Approach 1:
The patent applies different characteristics to different parts of the clock distribution system: buffers are placed at strategic locations along transmission paths to restore signal integrity, and trim circuits are applied locally to each buffer to adjust for specific distortion conditions at that location
Solution Approach 2:
The patent introduces buffer circuits as intermediary elements between the clock source and distant electrical circuits, where these buffers actively regenerate the clock signal and compensate for distortion accumulated during transmission
4Productivity
If input/output speeds are increased to improve productivity, then data transfer rate increases, but duty cycle distortion becomes more severe
Solution Approach 1:
The patent performs duty cycle calibration during the manufacturing process before the device is put into operation, using trim circuits to pre-adjust buffer characteristics so that when high-speed operation begins, the clock signals are already optimized and resistant to distortion at those speeds
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 distortion 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.