Clock Scrambling Unit for EMI Reduction in Isolation Systems
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Solution Overview
Problem
Existing electrical isolation systems face challenges in reducing electromagnetic interference (EMI) at high clock frequencies, which can lead to failure in EMI compliance standards, particularly due to the precision clock's role in sampled data converters and the difficulty in predicting and mitigating EMI during system design.
Innovation Solution
The implementation of a scrambled clock signal with a reduced dominant peak value and a more dispersed energy distribution across the frequency spectrum, achieved through a clock scrambling unit that varies the clock signal's frequency and pulse width, helps maintain data recovery while reducing EMI by spreading energy distribution and lowering the dominant peak value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a precision low jitter clock is used to sample the input signal, then signal linearity is improved, but electromagnetic interference (EMI) increases causing failure in EMI compliance standards
Solution Approach 1:
The patent applies parameter changes by modifying the clock signal characteristics - specifically introducing controlled jitter and frequency variations to the clock signal. This transforms the clock signal from a precise, high-energy concentrated waveform to one with dispersed energy distribution, thereby reducing EMI while maintaining sufficient timing accuracy for data sampling
Solution Approach 2:
The patent introduces dynamic elements to the clock signal by varying its frequency and timing characteristics. The clock signal becomes dynamically adjustable with controlled variations rather than being static and precise, which disperses the spectral energy and reduces peak EMI emissions while still enabling functional data sampling
2Measurement precision
If the clock frequency is increased to improve data sampling accuracy, then measurement precision is improved, but EMI emissions increase
Solution Approach 1:
The patent changes the clock signal parameters by introducing controlled frequency deviations and timing jitter. This transforms the spectral distribution of the clock signal, spreading the energy across a wider frequency range and reducing the peak emissions at any single frequency, thereby lowering EMI while maintaining data sampling functionality
3Object-generated harmful factors
If short clock PCB traces and close placement are used to reduce EMI, then EMI is reduced, but device complexity and design difficulty increase
Solution Approach 1:
The patent extracts the EMI reduction function from the physical layout constraints (trace length, component placement) and transfers it to the signal characteristic domain. By modifying the clock signal itself to have dispersed spectral energy, the patent eliminates the need for complex layout optimizations and close component placement, thereby reducing design complexity while achieving EMI reduction
Data Source
AI summary
An isolation system and isolation device are disclosed. An illustrative isolation device is disclosed to include a transmitter side and receiver side separated by an isolation material. One or more components of the transmitter side operate on a clock signal whereas one or more components of the receiver side operate on a scrambled clock signal. The scrambled clock signal is generated to have a different energy distribution than the clock signal and is also generated to have a dominant peak value that is lower than the dominant peak value of the clock signal.