Ring Oscillator Error Detection and Reset for Harmonic Stability

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Solution Overview

Problem

Ring oscillators in electrical circuits are prone to generating harmonic frequencies due to noise and power supply issues, leading to unstable operation and oscillation at undesirable frequencies, which can cause circuit malfunction.

Innovation Solution

Incorporating monitoring and error correction circuitry that detects errors in the signal propagated through the ring oscillator, allowing for selective resetting of the oscillator to maintain error-free operation by tapping output nodes and using error detection and correction circuits to adjust logic states and reset the signal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If monitoring and error correction circuitry is added to detect and correct errors in the ring oscillator signal, then reliability is improved, but device complexity increases

Engineering Contradiction:

Improveoperational stabilityVSAvoidcircuit complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent introduces monitoring circuitry and error correction circuitry as intermediary components between the ring oscillator and the rest of the system. These intermediaries detect error events (such as harmonic oscillations) and generate correction signals to reset the oscillator, thereby improving reliability without requiring fundamental changes to the oscillator structure itself.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent implements a feedback mechanism where the monitoring circuitry continuously observes the ring oscillator output, detects error events, and feeds correction signals back to the oscillator through the error correction circuitry. This closed-loop feedback system automatically corrects harmonic oscillations and maintains stable operation at the fundamental frequency.

Inventive Principle:

Principle #23Feedback

2Ease of operation

If the ring oscillator is enabled with trigger signals routed through interconnects, then ease of operation is improved, but manufacturing precision deteriorates due to signal degradation and ringing

Engineering Contradiction:

Improveenable/disable controlVSAvoidsignal integrity

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The patent replaces the mechanical/electrical trigger signal routing through interconnects with a digital control mechanism. The enable input to the NAND gate provides digital control of the oscillator state, and the error correction circuitry uses digital logic to detect and correct signal integrity issues, effectively substituting analog signal conditioning with digital processing.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS10483951B2Techniques for detecting and correcting errors on a ring oscillator

Publication Date: 2019.11.19 ALTERA CORP

AI summary

A circuit may include a ring oscillator circuit and monitoring circuitry. The ring oscillator circuit has a group of inverters in a loop, whereby the group of inverters includes first, second, and third output nodes. The monitoring circuitry may monitor for error events in a signal that has passed through the inverters from any one of the first, second, or third output nodes, and may generate first and second monitoring circuitry outputs. The circuit may further include an error correction circuit that produces an error correction output based on the first and second monitoring circuitry outputs. Accordingly, the monitoring circuitry may generate first and second updated monitoring circuitry outputs based on the error correction output. The first and second updated monitoring circuitry outputs may be logically combined using a logic circuit to reset the signal that has passed through the loop.