Programmable Ring Oscillator Calibration for Chip Temperature Sensing
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Solution Overview
Problem
Monitoring temperature in semiconductor systems is challenging due to the increased size and cost associated with adding temperature sensors, and existing solutions do not effectively calibrate chip-level module parameters dependent on temperature.
Innovation Solution
A programmable ring oscillator is used to calibrate delay elements for pulse width modulation and serve as a temperature sensor, determining the optimal number of delay elements based on pulse counting thresholds to avoid counter saturation and achieve accurate temperature measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are added to monitor temperature, then temperature monitoring capability is improved, but system size and cost increase
Solution Approach 1:
The ring oscillator serves dual purposes: it functions as a temperature sensor and as a calibration source for delay elements. By making the ring oscillator programmable and configurable, a single circuit structure achieves multiple functions that would traditionally require separate components, thereby improving temperature monitoring capability without proportionally increasing system size
Solution Approach 2:
The patent changes the operational parameters of the ring oscillator by making it programmable. The oscillator can be configured with different numbers of delay elements and operated at different frequencies to optimize its performance for temperature sensing across various operating conditions, allowing accurate temperature monitoring without requiring additional hardware
2Measurement precision
If the number of delay elements in the ring oscillator is increased to improve temperature resolution, then measurement precision is improved, but counter saturation risk increases
Solution Approach 1:
The ring oscillator is designed to be dynamically configurable, allowing the number of delay elements to be adjusted based on operating conditions. This dynamic reconfiguration enables the system to optimize between temperature resolution and counter saturation risk by adapting the oscillator frequency and delay element count to match the current measurement requirements
Solution Approach 2:
The system incorporates feedback mechanisms that monitor the ring oscillator output and adjust the number of delay elements accordingly. When the counter approaches saturation, the feedback control reduces the number of delay elements or adjusts the oscillation frequency, thereby preventing saturation while maintaining optimal temperature measurement resolution
3Adaptability or versatility
If the ring oscillator is made programmable to optimize temperature sensing, then adaptability is improved, but device complexity increases
Solution Approach 1:
The ring oscillator is pre-configured with a set of delay elements that can be selectively activated. The programmable logic is designed to select from predetermined configurations, which simplifies the control architecture compared to fully dynamic reconfiguration. This preliminary structuring allows optimization for temperature sensing while limiting the complexity growth that would result from completely flexible programming
Data Source
AI summary
A method of programming a ring oscillator for use as a temperature sensor comprises selecting an initial number of delay elements for use in a ring oscillator. The method further comprise starting a system clock counter and counting pulses of the ring oscillator until the system clock counter reaches a programmed value. The method also comprises determining whether a number of counted ring oscillator pulses is between lower and upper count thresholds and changing the number of delay elements for the ring oscillator as a result of the number of counted ring oscillator pulses being less than the lower count threshold or greater than the upper count threshold.