Optically Isolated Bias Trimming Circuit for Amplifiers
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Solution Overview
Problem
Conventional amplifiers require manual trimming and expensive manufacturing processes to adjust bias voltages, which can be time-consuming and prone to inaccuracies, and do not account for component aging, leading to potential signal distortions and increased power consumption.
Innovation Solution
A bias circuit that utilizes an optical coupling arrangement to provide a bias voltage based on an output signal, allowing for post-production tuning and electrical isolation, thereby eliminating the need for manual trimming and enabling adjustments due to component aging, while maintaining low production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual trimming is used to adjust bias voltage, then manufacturing precision is improved, but productivity deteriorates and device complexity increases
Solution Approach 1:
The patent replaces the mechanical manual trimming process with an optical control system. An optocoupler converts control voltages into optical signals that adjust the bias voltage automatically, eliminating the need for manual mechanical adjustment while maintaining precision and enabling parallel production.
Solution Approach 2:
The patent introduces an optocoupler as an intermediary device between the control circuit and the bias voltage generation circuit. This intermediary converts electrical control signals into optical signals, providing precise automatic control of bias voltage without direct mechanical intervention, thus improving both precision and productivity.
2Manufacturing precision
If manual trimming is used to adjust bias voltage, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The manual mechanical trimming process is replaced by an automatic optical control system using an optocoupler. This substitution maintains the precision of bias voltage adjustment while dramatically simplifying the manufacturing process, as the automatic system requires no skilled manual intervention and can be integrated into standard production lines.
Solution Approach 2:
The bias voltage adjustment system becomes self-regulating through the optocoupler-based automatic control mechanism. The system automatically adjusts the bias voltage based on control signals without requiring external manual trimming operations, making the manufacturing process easier and more consistent.
3Productivity
If fixed bias voltage is used during manufacturing, then productivity is improved, but reliability deteriorates due to component aging
Solution Approach 1:
The patent transforms the static fixed bias voltage into a dynamic adjustable bias voltage through the optocoupler control system. The bias voltage can be automatically adjusted in response to component aging and drift, maintaining reliability while the system remains productive. The dynamic nature allows real-time compensation for aging effects.
Solution Approach 2:
The optocoupler-based system enables feedback control of the bias voltage. By monitoring the actual bias conditions and adjusting through the optical coupling, the system compensates for component aging and drift, maintaining long-term reliability without sacrificing production efficiency.
4Reliability
If electrical isolation is implemented using optical coupling, then reliability is improved, but device complexity increases
Solution Approach 1:
The optocoupler serves as an intermediary that provides electrical isolation between control circuits and power circuits. By converting control signals into optical signals, it achieves reliable galvanic isolation without requiring complex isolation transformers or multiple separate control systems, thus improving reliability with minimal added complexity.
Solution Approach 2:
Traditional electrical isolation methods using heavy transformers or complex circuitry are replaced by the optocoupler's optical isolation mechanism. This substitution achieves the same reliability benefit of electrical isolation while significantly reducing circuit complexity and component count.
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
This solution allows for precise adjustment of bias voltages after manufacturing, reducing production costs, avoiding signal distortions, and conserving energy by optimizing cross currents through amplifying devices, thus enhancing the operational efficiency and reliability of amplifiers.
Implementation Method 1
an optical coupling arrangement which provides for an electrical isolation
Data Source
AI summary
An amplifier includes an amplifying device and a bias circuit for providing a bias voltage for the amplifying device. The bias circuit is configured to provide the bias voltage in dependence of an output signal of an optical coupling arrangement which provides for electrical isolation.