LED Emulator for Isolated Gate Driver Communication
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Solution Overview
Problem
Existing high voltage gate driver circuits face challenges in efficiently transmitting communication signals across isolation termination regions between different voltage domains, relying on LED optocouplers which are still in development, and lack efficient alternatives for emulation.
Innovation Solution
A communication system utilizing a light emitting diode (LED) emulator that translates modulated supply current into sense voltage, a voltage comparator to generate modulated output signals based on communication voltage thresholds, and a transmitter to create communication signals, enabling effective data transmission across voltage domains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LED optocouplers are used to transmit signals across the isolation termination region, then signal transmission between voltage domains is achieved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent uses an LED emulator that copies the electrical characteristics and behavior of a real LED optocoupler without requiring actual optical components. The emulator replicates the forward voltage-drop relationship and current modulation effects through electronic circuitry, achieving the same signal transmission function with simpler, fully-electronic implementation that avoids optical alignment and packaging complexities
Solution Approach 2:
The patent replaces the optical-mechanical system of LED optocouplers (which require light emission, detection, and precise optical coupling) with a purely electrical system. The LED emulator uses voltage-controlled current sources and resistance networks to simulate optocoupler behavior, eliminating mechanical and optical components while maintaining signal transmission across the isolation barrier
2Loss of information
If LED optocouplers are used for signal transmission, then data can be transmitted across isolated circuits, but manufacturing precision requirements increase
Solution Approach 1:
The LED emulator copies the electrical I-V characteristics of an LED optocoupler using voltage-controlled sources and resistance networks. This electronic replication eliminates the need for precise optical alignment and packaging that would otherwise be required to ensure accurate data transmission through the optocoupler, while maintaining the same information fidelity
Solution Approach 2:
By replacing the optical detection mechanism with an electrical voltage comparator that monitors the emulator output voltage, the system eliminates requirements for optical alignment precision, photodetector positioning, and lens focusing. The electrical measurement approach is inherently more tolerant to manufacturing variations
3Adaptability or versatility
If LED optocouplers are implemented, then communication across voltage domains is enabled, but ease of manufacture decreases
Solution Approach 1:
The LED emulator is implemented using standard electronic components (voltage-controlled current sources, resistors, voltage comparators) that are readily available and easy to manufacture using conventional semiconductor fabrication processes. This electronic copy approach avoids the specialized packaging and assembly required for real LED optocouplers, significantly improving ease of manufacture while maintaining voltage domain isolation capability
Solution Approach 2:
The patent replaces the complex optical assembly process with a purely electrical implementation that can be integrated into standard semiconductor manufacturing workflows. The LED emulator circuitry uses conventional electronic components and fabrication techniques, eliminating the need for optical bonding, alignment, and sealing processes that make LED optocoupler manufacturing difficult
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 reliable and efficient communication across isolated voltage domains, enhancing the performance of gate driver systems by providing an alternative to LED optocouplers and improving data transmission accuracy and speed.
Implementation Method 1
a light emitting diode (LED) emulator including an emulator input to be coupled to a supply generator and an emulator output configured to output a sense voltage, wherein the emulator input is configured to receive a forward current derived from a modulated supply, wherein the LED emulator is configured to translate the forward current into the sense voltage
Implementation Method 2
a voltage comparator including a comparator input coupled to the emulator output and including a comparator output, wherein the voltage comparator is configured to receive the sense voltage and translate the sense voltage into a modulated output signal based on a communication voltage threshold
Data Source
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AI summary
A communication system includes a supply generator configured to generate a modulated supply according to a data transmission; a light emitting diode (LED) emulator including an emulator input coupled to the supply generator and an emulator output configured to output a sense voltage, wherein the emulator input is configured to receive a forward current derived from the modulated supply and translate the forward current into the sense voltage; a voltage comparator coupled to the emulator output and configured to receive the sense voltage and translate the sense voltage into a modulated output signal based on a communication voltage threshold; and a transmitter coupled to a comparator output and configured to receive the modulated output signal and generate a communication signal according to the data transmission based on the modulated output signal.