Switchable Ring Oscillator Feedback for Random Bit Generation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing random number generators rely on expensive hybrid analog/digital circuits and are limited to specific ring oscillators without fixed points, restricting their implementation and increasing hardware requirements.
Innovation Solution
A digital ring oscillator circuit with switchable feedback paths generates random bits by periodically switching between feedback paths, allowing for the use of a broader class of oscillators and reducing hardware complexity, including the implementation of Fibonacci or Galois ring oscillators with switchover mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hybrid analog/digital circuits are used for random number generation, then randomness quality is improved, but hardware cost and complexity increase
Solution Approach 1:
The patent replaces analog noise sources with a digital ring oscillator circuit that generates random bits through digital logic operations. The ring oscillator uses digital gates (AND, OR, NOT) arranged in a feedback loop to produce unpredictable bit sequences, eliminating the need for expensive hybrid analog/digital circuits while maintaining randomness quality through purely digital mechanisms.
2Reliability
If specific ring oscillators without fixed points are used, then random bit generation is improved, but oscillator selection and implementation complexity increase
Solution Approach 1:
The patent introduces dynamic switching between multiple feedback paths in the ring oscillator circuit. A switching element periodically changes the feedback configuration, allowing the oscillator to adapt its structure during operation. This dynamic reconfiguration enables the use of broader classes of ring oscillators including those with fixed points, while maintaining random bit generation capability through the switching mechanism that prevents deterministic behavior.
Solution Approach 2:
The patent creates a universal ring oscillator architecture that can accommodate various oscillator types (Fibonacci, Galois, and oscillators with fixed points) through a common feedback switching mechanism. The switching element between first and second feedback paths allows the same circuit structure to support multiple oscillator configurations, greatly expanding oscillator selection flexibility without requiring separate dedicated circuits for each type.
3Device complexity
If ring oscillators with fixed points are used, then hardware simplicity is improved, but random signal quality deteriorates
Solution Approach 1:
The patent employs a feedback switching mechanism that periodically alters the feedback path in the ring oscillator. By switching between first and second feedback paths at predetermined times, the system introduces variability into the feedback signal, preventing the oscillator from settling into fixed deterministic patterns even when using oscillators with fixed points. This feedback switching maintains random signal quality while allowing hardware simplicity.
Data Source
AI summary
A device (1) for generating a random bit sequence has a digital ring oscillator circuit (2) having at least one first feedback path (R8) and one second feedback path (R14). To this end, a changeover is performed between the feedback paths (R8, R14) at times which can be predetermined, and a random signal (OS) having a random level history can be tapped at an output node (4) of the ring oscillator circuit (2).