Ring Oscillator Random Number Circuit Using Metastable Pulse Timing
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Solution Overview
Problem
Conventional random number generators using natural phenomena are complex, prone to external noise, and unsuitable for miniaturization into compact, low-power integrated circuits, which are essential for high-performance applications in ultra-compact and thin high-technology equipment.
Innovation Solution
A random number generator is designed with a loop of delay circuits and a pulse generation circuit producing pulses shorter than the total delay time, utilizing a counter to generate true random numbers based on the longevity of metastable states, thereby achieving miniaturization and reduced power consumption while maintaining high performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional random number generators utilize natural phenomena such as thermal noise or radioactive rays, then true random numbers can be generated, but the circuit scale increases and the design becomes complicated
Solution Approach 1:
The patent extracts only the essential function of random number generation by removing complex analog elements (amplifiers, waveform shaping circuits, uniformity optimization circuits) and retaining only the core metastable state generation mechanism through a simple flip-flop circuit with controlled input signals
Solution Approach 2:
The patent replaces physical/natural phenomena (thermal noise, radioactive decay) with an electronic circuit mechanism (metastable state in a flip-flop) that achieves the same random number generation function through electrical signals and timing control
2Reliability
If conventional random number generators utilize thermal noise, then random numbers can be generated, but the system becomes susceptible to external noise and operates less reliably
Solution Approach 1:
The patent converts the potential harm of noise susceptibility into a benefit by using controlled, deterministic input signals with precise timing characteristics to trigger metastable states, thereby eliminating reliance on noisy natural phenomena while maintaining true random number generation
Solution Approach 2:
The patent uses simple, transient metastable states in digital circuits that naturally decay quickly, replacing complex and vulnerable analog noise sources with robust, short-lived digital states that are inherently resistant to external noise interference
3Use of energy by moving object
If random number generators are miniaturized for ultra-compact equipment, then power consumption and size are reduced, but circuit complexity increases
Solution Approach 1:
The patent merges multiple functions (random number generation, timing control, and signal conditioning) into a single integrated flip-flop circuit with carefully timed input signals, eliminating the need for separate analog components and reducing overall circuit complexity while maintaining miniaturization benefits
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
The solution enables the creation of a compact, low-power random number generator with high performance, capable of producing true random numbers without ordinality, addressing the limitations of existing technologies by simplifying the circuit design and enhancing reliability.
Implementation Method 1
In the loop, a metastable state occurs having a longevity of '0', '1' or binarized to generate true random number data
Data Source
AI summary
A random number generator includes a ring oscillator having an EX-OR gate and four inverters together forming a loop. This loop enters stable state for a start signal having the low level and oscillates for the start signal having the high level. When the start signal has a pulse of a width shorter than the loop's delay time, output nodes responsively, sequentially enter metastable state hovering between the high and low levels. The metastable waveform becomes smaller with time and finally disappears. As metastable state cannot be controlled in longevity, it disappears at any random number node. A counter thus outputs a signal serving as true random number data depending on the longevity of the metastable state. A random number generator miniaturized and having reduced power consumption, and of high performance can thus be implemented.