Resistor Linearization via Compensation Circuit
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Resistor non-linearity in data converter circuits leads to non-linear data conversion due to self-heating effects, particularly pronounced in integrated thin-film resistors with low thermal conductivity materials like silicon dioxide, resulting in non-linear relationships between voltage and current.
Innovation Solution
A compensation circuit using first and second compensation resistors with identical nominal resistances but different geometric dimensions to produce a nonlinear voltage divider, coupled with current compensation resistors that convert the nonlinear voltage to a compensation current, effectively mitigating the non-linearity of the summing current resistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thin-film resistors are used in data converter circuits, then manufacturing precision is improved, but resistor non-linearity worsens due to self-heating effects from low thermal conductivity
Solution Approach 1:
The patent introduces an intermediary compensation circuit that includes a temperature sensor and control circuitry. This intermediary system monitors the temperature of the thin-film resistor and dynamically adjusts circuit parameters to compensate for self-heating effects, thereby maintaining linearity without changing the fundamental resistor structure
Solution Approach 2:
The patent employs parameter changes by dynamically adjusting the operating parameters of the data converter circuit based on temperature feedback. The control circuit modifies voltage or current parameters to counteract the resistance changes caused by self-heating, thus maintaining linear operation across varying temperature conditions
2Productivity
If resistor current is increased to improve productivity, then data conversion speed is improved, but non-linearity worsens due to increased self-heating
Solution Approach 1:
The patent implements a feedback mechanism where a temperature sensor continuously monitors the resistor temperature and feeds this information back to a control circuit. The control circuit then adjusts the operating parameters in real-time to compensate for temperature-induced non-linearity, enabling high current operation while maintaining accuracy
Solution Approach 2:
The temperature sensor and control circuit act as intermediary elements between the high-current resistor and the digital output. This intermediary system decouples the relationship between current magnitude and linearity, allowing high productivity operation without sacrificing measurement accuracy
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 achieves a parts-per-million range non-linearity correction, ensuring linear operation of data converter circuits by compensating for the non-linear resistance changes caused by temperature and voltage variations in the summing current resistor.
Implementation Method 1
resistor nonlinearity occurs due to self-heating of the resistor according to a nonzero temperature coefficient of resistance. As a resistor carries more current it dissipates power and heats up
Implementation Method 2
resistor nonlinearity occurs due to self-heating of the resistor according to a nonzero temperature coefficient of resistance
Data Source
AI summary
A converter circuit is provided that includes an amplifier circuit and further includes: a summing current resistor that exhibits nonlinear resistance coupled between a voltage node and a summing current node of the amplifier; a compensation resistor circuit includes resistors that exhibit nonlinear resistance; the compensation resistor circuit produces a compensation current at the summing current node that compensates for nonlinear current flow in the summing current resistor.