Op Amp Offset Voltage Correction Circuit for Wireless Charger Stability
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Solution Overview
Problem
The input offset voltage generated by operational amplifiers due to manufacturing process variations and semiconductor properties affects the stability and accuracy of systems, and conventional correction methods using external components often worsen the performance.
Innovation Solution
A driving device with an arithmetic processing unit and an offset voltage correction unit that senses the offset voltage using a sensing resistor, utilizing a power activating delay circuit, comparator, and logic control circuit to reset the offset voltage to zero, maintaining the operational amplifier's performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional correction methods using external components are used to eliminate input offset voltage, then the offset voltage can be corrected, but the chip performance deteriorates due to additional external factors affecting the input offset voltage again
Solution Approach 1:
The invention extracts the offset voltage correction function from external components and integrates it into the arithmetic processing unit itself. The offset voltage correction unit is built inside the chip, eliminating the need for external correction components that would reintroduce external factors affecting performance.
Solution Approach 2:
The invention merges the offset voltage correction functionality with the arithmetic processing unit by integrating the offset voltage correction unit directly into the chip architecture. This combines the sensing, comparison, and correction functions within the same integrated circuit, avoiding external component interactions.
2Manufacturing precision
If wafer test or final level test is used in OTP process for correction, then offset voltage can be corrected, but additional external components are required which affect input offset voltage and worsen op amp performance
Solution Approach 1:
The invention extracts the correction functionality from external test equipment and OTP processes, integrating it directly into the arithmetic processing unit. The offset voltage correction unit operates autonomously within the chip, eliminating external test and correction components.
Solution Approach 2:
The arithmetic processing unit performs self-correction of its offset voltage through the integrated offset voltage correction unit. The system monitors its own offset voltage and automatically corrects it without requiring external test equipment or additional correction components.
3Device complexity
If no correction is applied, then the device structure remains simple, but the input offset voltage deteriorates the op amp and affects system stability
Solution Approach 1:
The invention merges the offset voltage correction functionality with the existing arithmetic processing unit structure. The offset voltage correction unit shares the same integrated circuit substrate and power supply, minimizing additional structural complexity while providing continuous stability correction.
Data Source
AI summary
A driving device with correction function is provided herein and utilizes a sensing resistor to detect the variation in an operation amplifier. A signal generated by an offset voltage correction circuit is fed back to the operation amplifier and the offset voltage of the abnormal input in the operation amplifier is corrected to be zero so as to keep the operation amplifier under the best performance condition. The driving device implements in the wireless charger driving system can enhance the accuracy of the current value and can achieve good output performance and better system stability.