Adjustable Ring Oscillator Entropy Circuit for Stable Randomness
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Solution Overview
Problem
Conventional entropy source circuits lack the ability to dynamically adjust signal parameters, resulting in the generation of entropy values with poor quality.
Innovation Solution
An entropy source circuit comprising a first adjustable ring oscillator, a sampling circuit, and a control circuit that dynamically adjusts the oscillating clock signal frequency by switching between different settings based on detected distribution conditions to ensure high-quality entropy value generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the entropy source circuit uses fixed signal parameters, then the circuit structure is simple, but the entropy value quality is poor
Solution Approach 1:
The patent applies the dynamics principle by making the ring oscillator's operating frequency adjustable rather than fixed. The control circuit dynamically switches between first and second settings to change the oscillating clock signal frequency, allowing the entropy source to adapt to different operational conditions and maintain high-quality entropy generation throughout the device lifecycle.
Solution Approach 2:
The patent implements parameter changes by modifying the oscillating clock signal frequency parameter. The control circuit changes the frequency parameter of the ring oscillator between different values (first and second settings) based on detected distribution conditions, thereby optimizing entropy value quality without fundamentally changing the circuit architecture.
2Adaptability or versatility
If the entropy source circuit lacks dynamic adjustment mechanism, then the device complexity is low, but the adaptability to different conditions is poor
Solution Approach 1:
The patent applies feedback by implementing a closed-loop control mechanism. The control circuit detects the distribution of sampling values and uses this feedback information to determine whether to switch the ring oscillator between first and second settings. This feedback-driven approach enables the entropy source to automatically adapt to changing conditions while maintaining a relatively simple control structure.
3Reliability
If the ring oscillator operates at a single frequency, then the device complexity is reduced, but the entropy generation quality deteriorates
Solution Approach 1:
The patent implements universality by designing the ring oscillator to perform multiple functions through frequency switching. The same oscillator circuit can operate at different frequencies (first and second settings) to generate high-quality entropy values under various conditions, eliminating the need for multiple dedicated oscillators and reducing overall device complexity while maintaining entropy generation quality.
Data Source
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AI summary
An entropy source circuit (100) characterized by: a first adjustable ring oscillator (RO_1) operating in a first or a second setting, for respectively generating a first or a second oscillation clock signal (OS_1, OS_2) which have different frequencies under the first or the second setting; a first sampling circuit (SC_1), for respectively sampling the first and the second oscillating clock signal (OS_1, OS_2) according to the sampling frequency to generate first and second sampling values (SV_1, SV_2); a first detection circuit (DC_1) detecting a first distribution of the first sampling values (SV_1); and a control circuit (101) switching the first setting to the second setting when the first distribution does not meet a predetermined distribution. The entropy source circuit outputs entropy values according to t the first sampling values (SV_1) or the second sampling values (SV_2).