Capacitive Isolated Receiver Circuit for Signal Edge Preservation
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Solution Overview
Problem
Existing galvanic isolation techniques, such as differential signaling and capacitive coupling, face challenges in preserving signal edges and achieving low pulse width distortion due to current surges and high voltage transients, especially in applications with large voltage differences like electric vehicles.
Innovation Solution
A receiver circuit using two comparator circuits to detect the presence or absence of first and second signal states in a modulated signal, combined with a logical OR gate and low-pass filter to determine the carrier signal presence and filter high-frequency noise, allowing for accurate demodulation and reduced pulse width distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If OOK modulation with squaring and filtering is used for galvanic isolation, then detection simplicity is improved, but pulse width distortion increases and signal edges are not preserved
Solution Approach 1:
The receiver is divided into multiple independent comparator circuits, each dedicated to detecting specific signal states. This segmentation allows precise detection of signal edges without the distortion caused by squaring operations, while maintaining detection simplicity through the modular comparator architecture.
Solution Approach 2:
Comparator circuits are introduced as intermediary elements between the modulated signal and the detection logic. These comparators accurately detect signal state transitions and generate clean digital outputs, serving as a mediator that preserves signal edges while enabling simple digital processing.
2Reliability
If capacitive coupling is used for galvanic isolation, then voltage domain isolation is improved, but current surges and high voltage transients damage circuits
Solution Approach 1:
Capacitors are used as intermediary elements that couple signal paths between voltage domains while blocking direct current flow. This allows voltage isolation to protect against current surges and high voltage transients, while still permitting AC signal transmission for data communication.
Solution Approach 2:
The patent replaces direct electrical connections (mechanical/electrical contact) with capacitive coupling, substituting a physical connection that allows current flow with an electric field-based coupling that provides isolation while maintaining signal transmission.
3Reliability
If differential signaling with modulation is used, then galvanic isolation is achieved, but signal propagation delays and power consumption increase
Solution Approach 1:
The patent extracts and eliminates complex modulation and demodulation circuitry from the communication system. By using simple OOK modulation with direct comparator detection, it removes unnecessary power-consuming elements while maintaining galvanic isolation through capacitive coupling.
Solution Approach 2:
The patent employs simple, low-cost comparator circuits instead of complex modulation/demodulation systems. These simple comparators consume minimal power and can be easily replaced or reset, providing an energy-efficient alternative to traditional differential signaling with sophisticated modulation schemes.
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 approach enables quick and accurate detection of carrier signals, preserving signal edges and reducing pulse width distortion, which is crucial for applications encoding data using pulse width, and can operate at lower clock speeds, reducing power consumption and manufacturing costs.
Implementation Method 1
circuits may be galvanically isolated using capacitive coupling on signal paths between the circuits
Data Source
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AI summary
In some embodiments, a receiver circuit is configured to receive a modulated signal from a transmitter that is galvanically isolated from the receiver circuit. The receiver circuit is configured to demodulate the modulated signal by using two comparator circuits that respectively detect the presence or absence of first and second signal states of a carrier signal. Based on the detection of the first and second states, the receiver circuit determines whether the carrier signal is present or absent in the modulated signal to determine a demodulated value of the modulated signal.