Current-Mode OOK Demodulation for Fast Noise-Immune Isolators
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Solution Overview
Problem
On-off key (OOK) signal isolators face inefficiencies due to limited noise immunity and slow data rate transmission, primarily because of the use of multipliers and integrators in receivers, which struggle with common mode noise and high data rate applications.
Innovation Solution
A receiver system that processes OOK signals in the current domain, utilizing mismatched differential pair circuits and current mirrors to generate distinct current levels for different signal states, and an output driver to convert these currents into voltage representations, enhancing speed and noise immunity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a multiplier (or mixer) and an integrator are used as an energy detector for OOK demodulation, then the receiver can detect the presence or absence of the periodic signal, but the receiver has limited ability to handle common mode noise and is very slow for high data rate transmission
Solution Approach 1:
The patent changes the operating domain from voltage to current by using current-mode differential pair circuits and current mirrors. This parameter change enables the receiver to achieve both high speed (current mode operation) and improved noise immunity (differential current comparison that rejects common mode noise) simultaneously, resolving the technical contradiction between speed and reliability
2Measurement precision
If an integrator is used for OOK demodulation, then the receiver can detect signal energy, but the integrator is very slow for applications requiring high data rate transmission
Solution Approach 1:
The patent replaces the traditional voltage-mode integrator with a current-mode differential pair circuit system. This substitution eliminates the slow integration process while maintaining signal detection accuracy through differential current comparison, thereby achieving both precise measurement and high productivity
Data Source
AI summary
A receiver system for an on-off key (“OOK”) isolator system may include a pair of receivers. A first receiver may generate a first current signal representing a received OOK signal, and a second receiver may generate a second current signal from a common mode representation of the received OOK signal. The receiver system may include circuitry to compare the first and second current signals and generate an output signal therefrom.