Counter-Based Clock Adaptation for Single-Cycle Duty and Phase Control
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Solution Overview
Problem
Conventional clock signal adaptation circuits, such as those using phase-locked loops (PLLs) and digital delay lock loops (DLLs), face limitations in complexity, power consumption, and efficiency, particularly in updating duty cycle correction, phase shifting, and multiplication operations within a single clock cycle, and are not adaptable across different integrated circuit topologies due to manufacturing variations.
Innovation Solution
A counter-based method and apparatus for clock signal adaptation that generates an oscillator signal, counts cycles within a period of the input signal, and adapts the signal characteristics during the next period, enabling duty cycle correction, multiplication, and phase shifting within a single clock cycle, with parameterizable operations for efficient logic usage and reduced complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If phase-locked loops (PLLs) are used for clock signal adaptation, then duty cycle correction and phase alignment can be achieved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces analog PLL mechanisms with a digital counter-based system. The counter increments on each input clock cycle and compares against a threshold value to generate the output clock, eliminating the need for analog phase detectors, charge pumps, and voltage-controlled oscillators. This substitution of mechanical/analog systems with digital ones reduces complexity while maintaining adaptation functionality.
Solution Approach 2:
The patent changes the operating parameters by using a programmable threshold value in the counter that can be adjusted to achieve different duty cycle corrections and phase alignments. Instead of analog tuning, the system uses digital parameter modification through the threshold register, allowing flexible adaptation without increasing hardware complexity.
2Reliability
If digital delay lock loops (DLLs) are used for clock signal adaptation, then duty cycle correction and phase shifting can be implemented, but device area and complexity increase
Solution Approach 1:
The counter-based circuit serves multiple functions: it performs duty cycle correction, phase shifting, and clock multiplication/division all through the same hardware structure. By making the circuit universal, the patent eliminates the need for separate DLL circuits for each function, thereby reducing the overall semiconductor die area while maintaining all required adaptation capabilities.
Solution Approach 2:
The patent extracts the essential function of phase shifting and duty cycle correction from complex DLL structures and implements it through a simplified counter mechanism. By taking out only the core timing adjustment functionality and implementing it digitally, the system achieves the same phase control without the bulky analog delay lines and multipliers found in traditional DLLs.
3Device complexity
If conventional counter-based circuits are used for duty cycle correction, then logic usage can be simplified, but update speed is limited to every two clock cycles
Solution Approach 1:
The patent implements preliminary action by pre-calculating the threshold value based on the desired duty cycle correction before the adaptation process begins. The counter is reset and incremented in advance during each input clock cycle, and the comparison with the pre-set threshold occurs at the optimal moment to enable single-cycle update capability. This preliminary preparation allows the system to achieve faster adaptation without increasing logic complexity.
4Manufacturing precision
If PLLs are used for clock signal adaptation, then manufacturing precision can be maintained, but adaptability across different IC topologies decreases due to process variations
Solution Approach 1:
The patent replaces analog PLL components that are sensitive to manufacturing process variations with digital counter logic that is inherently more robust to such variations. Digital counters and comparators have well-defined switching thresholds that are less affected by process, voltage, and temperature (PVT) variations compared to analog components, thereby improving cross-topology adaptability while maintaining clock signal stability.
Data Source
AI summary
A method and apparatus to implement clock signal adaptation is provided to characterize an input clock signal that is to be adapted and in response, generate adaptation updates at each subsequent clock cycle of the input clock signal. In a first embodiment, clock signal adaptation occurs through duty cycle correction (DCC) to substantially achieve a 50% duty cycle. In an alternate embodiment, clock signal adaptation occurs through a multiplication operation that is applied to the clock signal to be adapted, whereby the multiplication operation is parameterizable to allow odd/even multiplication. In an alternate embodiment, clock signal adaptation occurs through a phase-shift operation that is applied to the clock signal to be adapted, whereby the phase-shift operation is parameterizable to allow all possible fractions and percentages of phase shifts.