Resistance Variation Detection Circuit Digital Current Adjustment
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Solution Overview
Problem
Existing resistance variation detection circuits face challenges with increased circuit area, precision decline, and noise susceptibility due to the need for multiple switch elements and high-precision A/D converters, especially when dealing with small resistor values and mixed physical dimensions of resistors.
Innovation Solution
A resistance variation detection circuit comprising a first and second resistor, current source circuits, and a voltage comparator, with a control circuit that digitally adjusts current supply to obtain the ratio of resistance values, allowing for digital data correction and reducing circuit area and noise susceptibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of bits involved in variation detection is increased, then the precision of resistance variation detection is improved, but the scale of the circuitry is enlarged owing to exponentiation of the number of bits
Solution Approach 1:
The patent transitions from spatial multiplication of resistors to temporal sequencing of current sources. Instead of providing N resistors for N-bit detection, the invention uses a single resistor with N differently-weighted current sources that are sequentially activated, converting a spatial problem into a temporal one and reducing circuit scale while maintaining detection precision.
Solution Approach 2:
A single resistor serves multiple functions: it is used in combination with each of the N differently-weighted current sources to perform detection for all N bit positions. This multi-functional use of one component eliminates the need for N separate resistors, directly addressing the circuit scaling problem while preserving measurement capability.
2Measurement precision
If a small resistor having a resistance value equivalent to one LSB is used, then the precision of variation detection is improved, but resistors of both large and small physical dimensions are mixed within the chip causing variation
Solution Approach 1:
Instead of changing the physical dimensions of resistors to achieve different resistance values, the patent changes the electrical parameter (current magnitude) while keeping the resistor physical dimensions uniform. The N current sources provide differently-weighted currents to a single uniform resistor, eliminating the need for mixed-size resistors and their associated fabrication variations.
Solution Approach 2:
The patent uses multiple copies of current source circuits with different weighting factors rather than creating physically different resistors. Each current source circuit is essentially a scaled version of the others, providing the necessary resistance variation detection through current magnitude differences rather than physical dimension differences.
3Manufacturing precision
If all resistors are implemented by a series connection of the shortest resistors, then the manufacturing precision is improved, but circuit area increases as a result
Solution Approach 1:
The patent merges the functions of N separate resistors into a single resistor used with N differently-weighted current sources. This consolidation reduces the total circuit area significantly while the current source weighting maintains the precision that would otherwise require multiple precisely-matched resistors in series or parallel configurations.
4Manufacturing precision
If a small resistor is implemented by a parallel connection of resistors having large resistance values, then the manufacturing precision is improved, but circuit area increases
Solution Approach 1:
The patent avoids creating small physical resistors entirely by using a single uniform resistor with differently-weighted current sources. The effective resistance values needed for N-bit detection are achieved through current magnitude variation rather than physical resistor size variation or parallel/series combinations, eliminating the area penalty associated with precision resistor networks.
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
The solution enables precise resistance variation detection with reduced circuit area and improved robustness against noise, allowing for effective correction of resistance variations and enhanced performance in semiconductor integrated circuits.
Implementation Method 1
a voltage comparator circuit for comparing a voltage across the first resistor and a voltage across the second resistor
Data Source
AI summary
A circuit for detecting variation of a resistance value of a resistor with respect to a reference value includes a first resistor; a second resistor; a first current source circuit for supplying current to the first resistor; a second current source circuit for supplying current to the second resistor; a voltage comparator circuit for comparing a voltage across the first resistor and a voltage across the second resistor; and a control circuit for digitally adjusting the supply current of at least one of the first or second current source circuit. A ratio of resistance values of the first and second resistors can be obtained from an adjustment value from the control circuit and result of comparison from the voltage comparator circuit.