Multi-Channel Driving Circuit With Randomized Delay for EMI Reduction
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Solution Overview
Problem
Conventional multi-channel driving circuits using regular time interleaving delay methods induce significant electromagnetic interference and deteriorate the signal-to-noise ratio due to high-order harmonic tones generated by simultaneous driving of post-stage loads.
Innovation Solution
A multi-channel driving circuit employing a random time interleaving method, where driving signals are adjusted with randomized time delays to avoid simultaneous high-level voltage transitions, reducing the instantaneously main peak current and high-order harmonic tones, thereby suppressing electromagnetic interference and improving signal-to-noise ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If regular time interleaving delay method is used to drive multiple post-stage loads, then the instantaneously main peak current is reduced, but high-order harmonic tones are generated causing electromagnetic interference
Solution Approach 1:
The patent applies preliminary action by pre-delaying multiple driving signals with different delay times before they reach the post-stage loads. This ensures that the loads are driven at different times, preventing simultaneous current peaks and reducing electromagnetic interference. The delay circuit introduces time offsets in advance, so when signals are combined, they do not create harmful interference patterns.
Solution Approach 2:
The patent employs periodic action through cyclic delay modulation, where delay times are varied in a cyclic manner across different channels. By setting delay times as T/4, T/2, and 3T/4 (where T is the signal period), the driving signals are distributed across different phases of the cycle, ensuring that peak currents do not coincide and electromagnetic interference is minimized while maintaining periodic operation.
2Power
If multiple driving signals are sequentially turned into high level voltage, then the instantaneously main peak current is lowered, but multiple high-order harmonic tones are generated deteriorating signal-to-noise ratio
Solution Approach 1:
The patent applies preliminary action by pre-delaying multiple driving signals with different delay times before they reach the post-stage loads. This ensures that the loads are driven at different times, preventing simultaneous current peaks and reducing electromagnetic interference. The delay circuit introduces time offsets in advance, so when signals are combined, they do not create harmful interference patterns.
Solution Approach 2:
The patent employs periodic action through cyclic delay modulation, where delay times are varied in a cyclic manner across different channels. By setting delay times as T/4, T/2, and 3T/4 (where T is the signal period), the driving signals are distributed across different phases of the cycle, ensuring that peak currents do not coincide and electromagnetic interference is minimized while maintaining periodic operation.
Data Source
AI summary
A driving method of a multi-channel driving circuit includes: receiving multiple driving signals corresponding to multiple to-be-driven elements, providing multiple randomized time delays, respectively adjusting the driving signals according to the randomized time delays to generate multiple delayed driving signals, and respectively driving the corresponding to-be-driven elements according to the delayed driving signals.