Auto-Zero Amplifier Leakage Control for Output Drift Stability
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Solution Overview
Problem
Conventional auto-zero techniques for operational amplifiers suffer from voltage drift over time due to leakage mismatch between switches, leading to inaccurate output voltages.
Innovation Solution
An auto-zero amplifier with a leakage control circuit that maintains equal voltage drops across switches, reducing leakage mismatch and stabilizing the output voltage by activating and deactivating auto-zero cycles and phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional auto-zero techniques are used to reduce offset voltage, then offset voltage is reduced, but output voltage drifts over time due to leakage mismatch
Solution Approach 1:
The patent implements a feedback mechanism where the secondary amplifier continuously monitors the voltage difference at its inputs caused by switch leakage, and the control circuit adjusts the hold phase duration dynamically to compensate for leakage mismatch, thereby maintaining output voltage stability over time
Solution Approach 2:
The patent transitions from static switch configuration to dynamic control by adjusting the hold phase duration based on detected leakage conditions, allowing the system to adapt to varying leakage mismatch and maintain stability
2Stability of the object's composition
If the hold phase duration is extended to maintain output voltage, then voltage stability improves, but leakage mismatch effects increase causing drift
Solution Approach 1:
The patent makes the hold phase duration dynamic rather than fixed, adjusting it based on the detected switch leakage characteristics to optimize the balance between stability and accuracy
Solution Approach 2:
The patent changes the temporal parameter (hold phase duration) based on leakage conditions, transforming a static timing parameter into a dynamic one that adapts to minimize drift while maintaining stability
Data Source
AI summary
According to an aspect, an auto-zero amplifier includes a main amplifier, a secondary amplifier connected to the main amplifier, a plurality of switching including a first switch and a second switch, and a leakage control circuit.