Ring Oscillator Logic-Path Loop for Low-Overhead IC Testing
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Solution Overview
Problem
The high cost and resource-intensive nature of system-level testing for integrated circuits, such as microcontrollers, due to the need for extensive routing outlay and high numbers of ring oscillators, which increases testing costs and overhead.
Innovation Solution
Implementing a ring oscillator circuit with a plurality of logic paths that form a natural loop, where each logic path is connected to the input multiplexer of the subsequent path, eliminating the need for long feedback lines and reducing routing outlay by using existing logic paths for both input and output directions, and enabling self-activation of ring oscillators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high numbers of ring oscillators are implemented in an integrated circuit, then measurement precision of performance is improved, but device complexity and routing outlay increase considerably
Solution Approach 1:
The patent merges multiple logic paths to form a single ring oscillator circuit, where the logic paths are connected in series to create oscillation. This combining approach reduces the total number of separate ring oscillators needed, thereby decreasing routing outlay and device complexity while maintaining measurement capability through the collective oscillation behavior of the integrated logic paths.
Solution Approach 2:
The patent makes existing logic paths within the integrated circuit serve dual purposes: their original functional purpose and their role as oscillation paths for performance testing. By utilizing the same logic paths for both normal circuit operation and ring oscillator functionality, the need for dedicated test structures is reduced, minimizing additional routing requirements and device complexity.
2Measurement precision
If comprehensive system level testing is performed to directly measure performance, then measurement precision is improved, but loss of time and testing costs increase
Solution Approach 1:
The patent implements self-activating ring oscillators that automatically generate oscillation signals without requiring external test equipment or complex system-level test setups. The logic paths themselves generate the oscillation through their inherent logic functionality, enabling autonomous performance measurement that reduces test duration and eliminates the need for expensive system-level testing infrastructure.
Data Source
AI summary
An integrated circuit includes a ring oscillator circuit and a plurality of logic paths. Each logic path comprises a path input connection, a path output connection and an input multiplexer, which has an output connection that is connected to the path input connection of the logic path. Each logic path, beginning with a first logic path, is assigned a respective subsequent logic path by virtue of the path output connection of the logic path being connected to a data input connection of the input multiplexer of the subsequent logic path. A last logic path of the logic paths is assigned the first logic path as subsequent logic path. For each logic path, the multiplexer is configured such that, when a control signal that indicates a test mode is fed thereto, it connects the data input connection of the input multiplexer to the path input connection of the logic path.