PLL Clock Frequency Tuning for Process Corner Variations
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Solution Overview
Problem
Digital systems face challenges in maintaining optimal clock frequencies due to variations in integrated circuit fabrication parameters, such as temperature and voltage, which affect the performance of electronic processors.
Innovation Solution
A method and apparatus that utilize a tuning logic controller and phase locked loop to determine and adjust clock frequencies based on integrated circuit process corners, ensuring the electronic processor operates within specified parameters by using a crystal oscillator and phase locked loop with a tuning logic controller to program and adjust frequencies accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed clock frequency is used in digital systems, then the system structure is simple, but the system cannot adapt to variations in fabrication parameters, temperature, and voltage
Solution Approach 1:
The patent implements dynamic clock frequency adjustment by using a phase-locked loop (PLL) that can programmably change its output frequency based on detected process corner conditions. The system transitions from a static fixed-frequency clock to a dynamic adaptive clock system that responds to real-time performance measurements, resolving the contradiction between adaptability and complexity.
Solution Approach 2:
The system employs feedback mechanisms where the performance of digital circuits is measured and used to determine process corners, which then feed back to adjust the clock frequency via the PLL. This closed-loop feedback system enables automatic adaptation to fabrication variations without manual intervention, achieving adaptability while managing complexity through automation.
2Reliability
If the clock frequency is adjusted to compensate for slow process corners, then the processor meets performance specifications, but energy consumption increases
Solution Approach 1:
The system dynamically changes the clock frequency parameter based on detected process conditions. By measuring actual circuit performance and identifying process corners, the system adjusts the clock frequency to the minimum necessary value that still meets performance specifications, thereby reducing energy consumption while maintaining reliability.
Solution Approach 2:
Instead of always running at maximum frequency to ensure performance compliance, the system applies partial action by using only the necessary clock frequency required for each specific process corner. This avoids excessive energy consumption while still meeting performance requirements through measured, targeted frequency adjustment.
3Adaptability or versatility
If multiple clock frequencies are supported for different process corners, then the system becomes more adaptable, but the control mechanism becomes more complex
Solution Approach 1:
The phase-locked loop is designed as a universal frequency synthesis device that can generate multiple clock frequencies through programmable division ratios and feedback mechanisms. This multi-functional PLL architecture supports adaptation to various process corners without requiring separate dedicated circuits for each frequency, thereby managing complexity while achieving versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for precise adjustment of clock frequencies, ensuring the electronic processor functions correctly across various process corners, thereby enhancing performance and reliability in digital systems.
Implementation Method 1
a clock having a crystal, for example, a quartz crystal that produces periodic vibrations when excited
Implementation Method 2
a phase locked loop receiving the reference signal and configured to generate the clock signal based on the reference signal
Data Source
AI summary
Method and apparatus for determining a clock frequency for an electronic processor are provided. One embodiment provides a clock generator for determining a clock frequency for an electronic processor and providing a clock signal to the electronic processor. The clock generator includes a crystal oscillator producing a reference signal and a phase locked loop receiving the reference signal and configured to generate the clock signal based on the reference signal. The clock generator also includes a tuning logic controller electrically coupled to the phase locked loop. The tuning logic controller is configured to program the phase locked loop to a first frequency and determine an integrated circuit process corner of the electronic processor. The tuning logic controller is also configured to determine a second frequency based on the integrated circuit process corner and program the phase locked loop to the second frequency.