Operational Amplifier Switching and ADC Averaging for Offset Drift
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Solution Overview
Problem
Existing operational amplifiers suffer from offset voltage errors and temperature drift, which are not effectively mitigated by prior solutions that require additional circuit space and increase manufacturing costs.
Innovation Solution
An integrated operational amplifier system that includes switch circuitry and an ADC to alternately generate output voltages based on input voltages and offset voltages, eliminating the need for external frequency filters by using an ADC to sample and average these voltages, thereby reducing offset and temperature drift.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external frequency filters are used to mitigate offset voltage errors and temperature drift, then operational amplifier performance is improved, but additional circuit space is required and manufacturing costs increase
Solution Approach 1:
The patent combines the operational amplifier and frequency filter into a single integrated circuit device, eliminating the need for external frequency filters. The filter circuit is merged within the op amp structure, reducing external component requirements and circuit space while maintaining the ability to mitigate offset voltage errors and temperature drift.
Solution Approach 2:
The integrated circuit is designed to perform multiple functions: operational amplification and frequency filtering within a single device. This multi-functionality eliminates the need for separate external frequency filter components, reducing circuit space and manufacturing complexity while maintaining error mitigation capabilities.
2Reliability
If external frequency filters are used to mitigate offset voltage errors and temperature drift, then operational amplifier performance is improved, but manufacturing costs increase
Solution Approach 1:
The patent combines the operational amplifier and frequency filter into a single integrated circuit device, eliminating the need for external frequency filters. The filter circuit is merged within the op amp structure, reducing external component requirements and circuit space while maintaining the ability to mitigate offset voltage errors and temperature drift.
Solution Approach 2:
The integrated circuit is designed to perform multiple functions: operational amplification and frequency filtering within a single device. This multi-functionality eliminates the need for separate external frequency filter components, reducing circuit space and manufacturing complexity while maintaining error mitigation capabilities.
3Manufacturing precision
If switch circuitry is used to alternately generate output voltages, then offset voltage and temperature drift are reduced, but device complexity increases
Solution Approach 1:
The patent employs periodic switching of the switch circuitry to alternately generate first and second output voltages. This periodic action modulates the offset voltage and temperature drift effects, allowing them to be filtered out by the integrated frequency filter. The switching occurs at a specific frequency that enables effective separation of the error signals from the useful output.
Solution Approach 2:
The patent converts the harmful effects of offset voltage and temperature drift into beneficial signals by modulating them through periodic switching. The error signals are transformed into AC components at the switching frequency, which can then be easily filtered out, leaving only the useful DC output. This approach turns the persistent error signals into removable AC artifacts.
Data Source
AI summary
An example device includes: switch circuitry configured to: connect, in a first state based on a control signal, a first switch input to a first switch output and a second switch input to a second switch output; and connect, in a second state based on the control signal, the first switch input to the second switch output and the second switch input to the first switch output; an operational amplifier configured to: generate, in response to the control signal, a first voltage based on a gain and the connections in the first state; and generate, in response to the control signal, a second voltage based on the gain and the connections in the second state; and an Analog to Digital Converter (ADC) configured to convert the first voltage and the second voltage into a digital value based on a multiplication of the input voltage and the gain.