Configurable Resistor Calibration via ADC Feedback
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Solution Overview
Problem
Integrated circuits face challenges in maintaining precise resistance values due to process variations, leading to inconsistent circuit performance across semiconductor substrates.
Innovation Solution
A configurable resistor system is implemented, utilizing a reference resistor and a current source circuit to adjust the resistance of the configurable resistor through an Analog-to-Digital Converter (ADC) and calculation circuit, allowing for calibration to achieve target resistance values by calculating and applying configuration codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If process variations are reduced to achieve consistent resistance values, then manufacturing precision improves, but device complexity increases due to calibration circuits
Solution Approach 1:
The configurable resistor performs self-calibration by comparing its own resistance against a reference resistor and automatically adjusting its configuration code to achieve the target resistance value, eliminating the need for external manual calibration processes
Solution Approach 2:
The calibration process dynamically changes the configuration parameter (resistance value) of the configurable resistor based on measured deviations from the target value, using feedback from the ADC and calculation circuit to iteratively adjust until the desired precision is achieved
2Measurement precision
If resistance measurement precision is increased to detect process variations, then measurement precision improves, but device complexity increases due to additional calibration components
Solution Approach 1:
The ADC and calculation circuit serve multiple functions: they measure the resistance of the configurable resistor, compare it against the reference resistor, calculate the required adjustment, and control the reconfiguration process, eliminating the need for separate dedicated measurement and control circuits
Solution Approach 2:
The reference resistor acts as an intermediary standard that enables precise measurement of the configurable resistor's deviation from the target value without requiring direct access to absolute resistance standards, simplifying the measurement system
Data Source
AI summary
An electrical circuit includes a configurable resistor and a reference resistor with a current source circuit coupled to provide a current to the configurable resistor and the reference resistor. An Analog-to-Digital Converter (ADC) is configured to convert voltages from the configurable resistor and the reference resistor to digital values. A calculation circuit is configured to calculate an adjustment for the configurable resistor from a digital reference value obtained from a reference resistor voltage and two or more digital values obtained from two or more voltages corresponding to two or more configurations of the configurable resistor. A sequencer adjusts the configurable resistor based on the adjustment calculated by the calculation circuit.