Opto-emulator Transmitter Linearity via Feedback Control
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Solution Overview
Problem
Opto-emulators face issues with non-linearity in the current transfer ratio (CTR) over time, which affects their performance and reliability compared to opto-couplers.
Innovation Solution
The proposed solution involves an opto-emulator transmitter circuit that includes a current controller, an oscillator circuit, and receiver replica circuitry, which work together to maintain a proportional output current to input current while improving linearity and immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If opto-emulators are used to provide isolated communications behavior, then speed, isolation, operational temperature range, and aging characteristics are improved, but non-linearity of the current transfer ratio IC/IF occurs
Solution Approach 1:
The patent implements a feedback mechanism where the output current from the opto-emulator is fed back to the input through a feedback resistor network. This feedback loop continuously adjusts the input current to compensate for non-linearity in the current transfer ratio, ensuring that the overall transfer characteristic remains linear despite the inherent non-linearity of the opto-emulator component.
Solution Approach 2:
The patent changes the operating parameters by introducing a feedback resistor network that dynamically adjusts the current transfer ratio. By varying the feedback resistance values, the system compensates for non-linearity across different operating conditions, maintaining linear behavior over a wide range of input and output current values.
2Manufacturing precision
If feedback control is added to improve linearity, then current transfer ratio linearity is enhanced, but device complexity increases
Solution Approach 1:
The feedback mechanism uses a simple resistor network connected between the output and input terminals, adding minimal complexity while achieving significant linearity improvement. The feedback resistors are directly integrated into the existing circuit topology without requiring additional active components or complex control logic.
Solution Approach 2:
The patent employs a simplified feedback model that replicates the non-linearity effect and compensates for it mathematically through resistor ratios. Instead of using complex digital control or lookup tables, the invention uses an analog feedback network that copies and corrects the non-linearity behavior through passive component ratios.
Data Source
AI summary
An opto-emulator transmitter includes: a current controller; an oscillator circuit; and receiver replica circuitry. The current controller has a first terminal, a second terminal, and a third terminal. The oscillator circuit has a first terminal, a second terminal, and a third terminal. The first terminal of the oscillator circuit is coupled to the second terminal of the current controller. The receiver replica circuitry has a first terminal, a second terminal, and a third terminal. The first terminal of the receiver replica circuitry is coupled to the second terminal of the oscillator circuit. The second terminal of the receiver replica circuitry is coupled to the third terminal of the oscillator circuit. The third terminal of the receiver replica circuitry is coupled to the third terminal of the current controller.