Digital Ring Oscillator Random Bits Without Fixed-Point Constraints
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Solution Overview
Problem
Existing random number generators require significant hardware outlay and are limited to specific ring oscillators due to the need to exclude fixed points, which restricts their implementation and increases energy consumption.
Innovation Solution
A digital ring oscillator circuit with logic components that can reach a stable fixed point, utilizing thermal or quantum mechanical processes to generate random signals, allowing a broader class of oscillators to be used, including Galois or Fibonacci oscillators, and reducing energy consumption by implementing the circuit with only digital components in CMOS technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If specific ring oscillators (Fibonacci or Galois) without fixed points are used, then random bit generation is achieved, but device complexity and implementation difficulty increase due to mathematical constraints
Solution Approach 1:
The patent inverts the conventional approach by accepting fixed points in ring oscillators rather than excluding them. Instead of designing oscillators that must avoid fixed points through complex mathematical constraints, the invention allows fixed points to exist and simply ensures the oscillator is not initially in a fixed point state, thereby simplifying the design while maintaining random bit generation quality
Solution Approach 2:
The patent changes the operational parameter of the ring oscillator by allowing it to operate in a regime where fixed points are acceptable. The key parameter change is the initial state configuration - ensuring the oscillator starts outside the fixed point state rather than designing the circuit topology to eliminate fixed points entirely
2Reliability
If ring oscillators without fixed points are used, then random signals are generated, but energy consumption increases and implementation becomes more difficult
Solution Approach 1:
The patent inverts the energy consumption issue by showing that allowing fixed points actually reduces energy consumption. Oscillators that can reach fixed points consume less energy because they can settle into stable states when appropriate, rather than requiring continuous energy input to maintain non-fixed-point operation
3Reliability
If hybrid analog/digital circuits are used for random number generation, then random numbers are generated, but hardware outlay increases significantly
Solution Approach 1:
The patent substitutes analog/mechanical noise sources with purely digital logic circuits. Instead of using analog noise generators that require hybrid analog/digital implementation, the invention uses digital ring oscillators whose inherent timing variations and logic gate delays provide the necessary randomness, eliminating the need for analog components
Solution Approach 2:
The patent creates a digital copy of the random number generation function that originally required analog components. By replicating the randomness generation capability using only digital logic gates and ring oscillators, the system achieves the same functional outcome with reduced hardware complexity and outlay
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 simple and cost-effective generation of high-quality random bit sequences with reduced energy consumption, suitable for use in security applications like RFID tags, and can be implemented in FPGA or ASIC circuits, achieving reliable randomness even when the ring oscillator reaches a fixed point.
Implementation Method 1
Thermal or quantum mechanical processes within the semiconductor components used to implement the oscillator cause for example phase fluctuations or jitter
Implementation Method 2
Thermal or quantum mechanical processes within the semiconductor components used to implement the oscillator cause for example phase fluctuations or jitter
Data Source
AI summary
A device generates a random bit sequence with a digital ring oscillator circuit comprising logic components. The circuit has an input node and an output node, wherein the digital ring oscillator circuit is designed such that oscillation occurs during a change of state of a logic start signal coupled on the input node, said oscillation having a fixed point, and wherein on the output node a random signal can be tapped having an arbitrary level curve.