Operational Amplifier SAR Trimming for Internal Offset Compensation
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Solution Overview
Problem
Modern operational amplifier trimming techniques face challenges in accurately adjusting parameters such as offset, gain, and temperature drift, often requiring external measurements and complex circuitry, which can increase production costs and time.
Innovation Solution
A system comprising operational amplifiers with a trimming circuit that employs Successive Approximation Register (SAR) logic to adjust operational parameters based on memory values, allowing for internal compensation of offset voltages without external measurements, using digital-to-analog converters to control internal transistors and resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external measurements and complex circuitry are used for trimming operational amplifiers, then trimming precision can be improved, but production time and costs increase
Solution Approach 1:
The operational amplifier uses its own output signal to perform the trimming measurement, eliminating the need for external measurement equipment. The device trims itself by monitoring its own offset voltage through its output, which is fed back to the trimming circuitry, thereby reducing production time while maintaining precision
Solution Approach 2:
The patent extracts the measurement function from external equipment and integrates it into the operational amplifier itself. By using the op-amp's own output signal for measurement purposes, the system eliminates external measurement circuitry and reduces production complexity and time
2Measurement precision
If external measurements are used for trimming operational amplifiers, then parameter accuracy can be improved, but circuit complexity increases
Solution Approach 1:
The patent merges the measurement function with the operational amplifier's existing output stage. The output signal that normally drives the load is simultaneously used for trimming measurements, combining two functions into one circuit path and reducing overall system complexity
Solution Approach 2:
The output signal of the operational amplifier serves dual purposes: driving the external load and providing the measurement signal for trimming. This multi-functionality eliminates the need for separate measurement circuitry, reducing complexity while maintaining measurement accuracy
3Reliability
If traditional trimming techniques are used, then offset compensation can be achieved, but production costs increase
Solution Approach 1:
The operational amplifier performs its own trimming using internally available signals and circuitry. By utilizing its own output signal and integrated trimming circuit, the device eliminates the need for expensive external measurement and trimming equipment, reducing production costs while maintaining offset compensation capability
Solution Approach 2:
The patent recovers and reuses the output signal for trimming measurements instead of discarding it. This signal recovery approach eliminates the need for separate measurement equipment, reducing production costs while maintaining trimming effectiveness
4Productivity
If simultaneous bit iteration is implemented in SAR logic, then trimming speed can be improved, but logic complexity increases
Solution Approach 1:
The patent segments the trimming process into parallel bit-position operations within the SAR logic. By dividing the iteration into simultaneous bit-position operations rather than sequential processing, the system achieves faster trimming speed while managing logic complexity through structured segmentation
Data Source
AI summary
Disclosed is a system comprising a plurality of operational amplifiers, each operational amplifier having individually adjustable operational parameters, and a trimming circuit. The trimming circuit includes successive approximation register (SAR) logic that determines associated memory values. The trimming circuit changes the adjustable operational parameters of each operation amplifier based on the associated memory values.