Clock Filter Calibration for Stable Noise-Resistant Timing
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Solution Overview
Problem
Existing clock filter devices face challenges in dynamically adjusting their cut-off frequency to prevent noise glitches and hacker attacks, which can cause instability and excessive power consumption, and are susceptible to changes in process parameters, voltage, and temperature.
Innovation Solution
A clock filter device comprising a reference clock generator, counters, and a controller that adjusts the cut-off frequency through calibration, using internal resistance-capacitance circuits to generate a reference clock and compare count values to determine optimal filtering settings, reducing reliance on delay chains and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the cut-off frequency is increased to allow higher frequency clocks to pass through, then the system can operate at higher frequencies, but noise glitches and hacker attacks can more easily penetrate the filter
Solution Approach 1:
The patent implements dynamic adjustment of the cut-off frequency through a calibration mode that uses counters and controllers to automatically optimize the filtering parameters. The system transitions from a static fixed cut-off frequency to a dynamic adjustable parameter that can be calibrated based on actual operating conditions, resolving the contradiction between allowing high-frequency signals and blocking noise.
Solution Approach 2:
The patent changes the physical parameter of cut-off frequency from a fixed design value to an adjustable parameter through calibration. By modifying the cut-off frequency parameter dynamically based on calibration results, the system can adapt to different operating conditions and maintain optimal noise filtering while allowing required clock frequencies to pass through.
2Adaptability or versatility
If multiple delay chains are added to adjust pulse widths for different frequencies, then the cut-off frequency can be adjusted, but the device complexity and power consumption increase
Solution Approach 1:
The patent extracts the frequency adjustment function from the delay chain structure and relocates it to a separate calibration module with counters and controllers. This separation allows the main filtering path to remain simple while the adjustment functionality is handled by a dedicated calibration subsystem, reducing overall device complexity.
Solution Approach 2:
The patent introduces a calibration mode as an intermediary mechanism between the input clock and the filtering operation. This calibration mode uses counters to measure signal characteristics and controllers to adjust parameters, acting as a mediator that enables frequency adaptation without requiring multiple complex delay chains in the main signal path.
3Productivity
If the cut-off frequency is set close to the operating clock frequency to minimize filtering impact, then signal transmission is optimized, but the filter becomes susceptible to hacker manipulation and environmental variations
Solution Approach 1:
The patent implements a feedback mechanism through the calibration mode, where the system measures the actual clock signal characteristics using counters and uses this feedback information to automatically adjust the cut-off frequency. This closed-loop feedback ensures the filter operates at optimal settings while being resistant to manipulation, as any attempts to alter the system would be detected and corrected by the calibration process.
Solution Approach 2:
The patent enables the clock filter to self-calibrate and self-adjust its parameters through the automated calibration mode. The system performs self-service by using its own resources (counters, controllers) to measure and optimize its filtering characteristics, making it autonomous and resistant to external manipulation attempts.
4Adaptability or versatility
If the pulse generator uses more delay units to widen the adjustable range of cut-off frequency, then frequency adaptability improves, but power consumption increases proportionally
Solution Approach 1:
The patent implements periodic calibration instead of continuous operation of multiple delay chains. The calibration mode is activated periodically or as needed to adjust the cut-off frequency, rather than maintaining multiple active delay chains continuously. This periodic action significantly reduces power consumption while maintaining the required frequency adaptability.
Solution Approach 2:
The patent dynamically activates only the necessary components during calibration rather than keeping all delay chains active. The dynamic switching between calibration mode and normal operation, along with selective activation of counters and controllers only when needed, reduces power consumption while maintaining full frequency adjustment capability when required.
Data Source
AI summary
A clock filter device for finding an optimal cut-off frequency of a clock filter through a controller to achieve an effective clock filtering is illustrated. Further, in the calibration mode, a reference clock that has not passed the clock filter and a reference clock that has passed the clock filter make a first counter and a second counter count respectively. After the first counter counts to a specific value, a count value of the second counter is obtained. The count values of the first counter and the second counter are compared to each other to determine whether the two values are approximate or not. When the two values are not approximate, the previous cut-off frequency of the clock filter is taken as the optimal cut-off frequency. Therefore, the clock filter can adopt the optimal cut-off frequency in a working mode to effectively filter out the noise an input clock.