Cross-Coupled Differential Receiver for Low-Power Isolated Data Links
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Solution Overview
Problem
Existing data isolators face challenges in efficiently isolating data signals between circuits operating at different voltages and ground potentials, often requiring high power consumption and lacking in accuracy and robustness, especially when using single-ended amplifiers.
Innovation Solution
A low power differential data isolator circuit is developed, featuring a transmitter, an isolator, and a differential receiver with cross-coupled single-ended amplifiers referenced to a time-varying potential, allowing for high-speed operation with the benefits of both differential and single-ended configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional single-ended receivers are used in data isolators, then device complexity is reduced, but signal accuracy and noise immunity deteriorate
Solution Approach 1:
The receiver is segmented into two separate single-ended amplifiers that process differential signals independently. Each amplifier handles one side of the differential pair, allowing the system to achieve differential signal accuracy benefits while maintaining the simplicity of single-ended amplifier design. The segmentation enables independent optimization of each amplifier path.
Solution Approach 2:
The patent merges the advantages of differential signaling (noise immunity, accuracy) with the simplicity of single-ended amplifier implementation. By combining two single-ended amplifiers to process differential inputs and outputs, the system achieves the signal accuracy of differential receivers without requiring complex differential amplifier circuits.
2Reliability
If high power consumption is accepted in data isolators, then signal robustness and noise immunity improve, but energy efficiency deteriorates
Solution Approach 1:
The receiver employs periodic resetting of the single-ended amplifiers to maintain signal integrity without requiring continuous high power consumption. The amplifiers are reset at appropriate intervals to prevent saturation and maintain robust signal detection, enabling reliable operation with reduced average power consumption compared to continuously powered differential receivers.
3Object-affected harmful factors
If single-ended amplifiers are used in receivers, then power consumption is reduced, but common mode rejection and noise immunity deteriorate
Solution Approach 1:
The patent introduces asymmetry in the coupling configuration where the first single-ended amplifier couples to the first input terminal through a first coupling capacitor, and the second single-ended amplifier couples to the second input terminal through a second coupling capacitor. This asymmetric differential configuration enables common mode rejection by creating unequal signal paths that cancel common mode noise, while maintaining low power consumption through single-ended amplifier implementation.
Data Source
AI summary
Data isolators are described. The data isolators include a differential receiver having cross-coupled single-ended amplifiers. The single-ended amplifiers may be referenced to a time-varying reference potential. The cross-coupling of the single-ended amplifiers may provide high speed, low power consumption operation of the data isolator.