Digital Isolator Modulation Circuit for Pulse Width Equality
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Solution Overview
Problem
Existing digital isolators face challenges in maintaining the pulse width of input signals and output signals, which affects the quality and speed of signal transmission between galvanically isolated devices.
Innovation Solution
The communication device incorporates a modulation circuit with delay circuits that adjust the period length of modulated signals based on input logic levels, ensuring that the pulse width of input and output signals remains substantially equal, thereby enhancing signal quality and transmission speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a digital isolator uses magnetic field coupling by an isolation transformer or electric field coupling by an insulating capacitor to transmit signals between galvanically isolated devices, then signal transmission between primary-side and secondary-side devices is achieved, but the pulse width of input signals and output signals cannot be maintained equally, which limits signal transmission quality and speed
Solution Approach 1:
The patent applies preliminary action by adjusting the period length of the modulated signal in advance before transmission through the isolation transformer. The modulation circuit modifies the carrier wave period based on the input signal characteristics, pre-compensating for expected pulse width distortions during galvanic isolation. This ensures that after transmission through the isolator, the output pulse width matches the input pulse width, thereby resolving the contradiction between transmission speed and pulse width equality.
2Productivity
If high-frequency modulated signals are input to the isolation transformer for efficient communication, then signal transmission efficiency is improved, but pulse width distortion occurs during transmission, affecting signal quality
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the period length of the carrier wave in the modulated signal. The modulation circuit changes the temporal parameters of the high-frequency carrier based on the input signal's pulse characteristics. By modifying the carrier period rather than using a fixed high-frequency carrier, the system maintains transmission efficiency while compensating for pulse width distortion, thus improving both productivity and reliability simultaneously.
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 high-quality, high-speed signal transmission between the primary-side and secondary-side devices by ensuring that the pulse widths of input and output signals are substantially equal, thus alleviating limitations on signal transmission speed.
Implementation Method 1
to transmit a signal between the primary-side device and the secondary-side device, magnetic field coupling by an isolation transformer or electric field coupling by an insulating capacitor is used
Implementation Method 2
to transmit a signal between the primary-side device and the secondary-side device, magnetic field coupling by an isolation transformer or electric field coupling by an insulating capacitor is used
Data Source
AI summary
According to one embodiment, a communication device includes first and second substrates. The first substrate includes an input circuit and a modulation circuit. The second substrate includes a receive circuit and an output circuit. The modulation circuit includes at least one delay circuit, outputs a modulated signal if an input signal has a first logic level, and using the at least one delay circuit, adjusts a length of a period to output the modulated signal shorter or longer than a period when the input signal has the first logic level. The receive circuit receives an electrical signal based on the modulated signal and demodulates the electrical signal. The output circuit outputs an output signal based on the electrical signal demodulated by the receive circuit.