Serial Resistor Network for Rapid Resistance Estimation
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Solution Overview
Problem
In integrated circuit applications, determining the resistance value of an external resistor using varying current is hindered by settling time due to parasitic reactance, leading to inefficiencies in resistance estimation.
Innovation Solution
A system comprising serially-connected resistors, a comparator, and switches allows for rapid resistance estimation by maintaining a non-time varying current and varying a voltage reference, enabling quicker determination of the external resistor's resistance value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If varying current through the external resistor is used to determine resistance value, then the resistance estimation can be performed, but settling time due to parasitic reactance increases the measurement time
Solution Approach 1:
Instead of varying the current through the external resistor to determine its resistance value, the patent inverts the approach by maintaining a constant current and varying a voltage reference. This inversion eliminates the settling time issue caused by parasitic reactance while still enabling resistance determination through comparison.
Solution Approach 2:
The patent changes the parameter being varied from current to voltage reference. By keeping the current constant and varying the voltage reference, the measurement process avoids the settling time penalty associated with current changes, thereby improving measurement speed while maintaining accuracy.
2Measurement precision
If current is varied over a range to determine resistance value, then the resistance estimation can be performed, but the process requires additional settling time
Solution Approach 1:
The patent inverts the conventional measurement approach by maintaining constant current and varying voltage reference instead of varying current. This inversion eliminates the need for settling time after current variation, significantly improving measurement efficiency and productivity.
Solution Approach 2:
By maintaining a constant current through the external resistor throughout the measurement process, the patent ensures continuous useful action without interruption for settling. The measurement proceeds continuously by comparing the constant voltage drop with varying voltage references, eliminating idle settling time and improving productivity.
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
This approach significantly reduces the time required to estimate the resistance value of an external resistor, improving efficiency compared to prior art methods by eliminating the need for additional settling time after current variation.
Implementation Method 1
comparing the voltage drop developed across the external resistor to a reference voltage
Implementation Method 2
settling time due to parasitic reactance
Data Source
AI summary
An integrated circuit comprising: a source comprising an output port; a set of serially-connected resistors electrically coupled to the output port of the source; a comparator comprising a first input port, a second input port, and an output port; a set of switches, each switch in the set of switches comprising a first terminal electrically coupled to the first input port of the comparator, and a second terminal electrically coupled to the set of serially-connected resistors; a current source comprising an output port electrically coupled to the second input port of the comparator; and a pin electrically coupled to the output port of the current source.