Switching Converter Clock Modulation for EMI Reduction
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Solution Overview
Problem
Switching converters generate parasitic electromagnetic interferences that affect FM radio reception, with existing solutions only partially optimizing emissions and not fully addressing additional frequency ranges or radio reception issues.
Innovation Solution
A switching converter with a modulated basic clock, where the clock generator varies the carrier frequency using specific modulation frequencies and a frequency deviation, optimizing electromagnetic emissions and preventing direct demodulation interference with FM radio signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the working clock frequency is varied using jitter, then electromagnetic emissions are reduced, but only partial optimization is achieved and FM radio reception issues are not fully addressed
Solution Approach 1:
The clock generator dynamically adjusts the working clock frequency by modulating a basic clock with multiple sinusoidal signals having different frequencies and amplitudes. This creates a continuously varying frequency spectrum that spreads electromagnetic emissions across a broader range, preventing concentration at specific frequencies that could interfere with FM radio reception.
Solution Approach 2:
The invention changes the frequency parameters of the working clock by superimposing multiple modulation frequencies (e.g., 100 Hz, 200 Hz, 500 Hz, 1 kHz) with different amplitudes on the basic clock. This multi-parameter frequency modulation creates a complex frequency trajectory that optimizes emission reduction across multiple frequency bands simultaneously.
2Object-generated harmful factors
If maximum frequency variation is applied, then emission reduction is maximized, but the switching converter control unit processing capability is stressed
Solution Approach 1:
The invention applies partial frequency variation by using multiple sinusoidal modulation signals with carefully selected amplitudes and frequencies rather than maximum possible variation. This provides sufficient emission reduction while keeping the frequency deviations within the reasonable processing capability of the switching converter control unit.
Solution Approach 2:
The clock generator uses periodic sinusoidal modulation signals with different frequencies and periods to vary the working clock frequency. This periodic action creates a structured frequency variation pattern that is easier for the control unit to process compared to random or irregular frequency changes, while still achieving effective emission reduction.
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
The solution significantly reduces electromagnetic emissions, making them indistinguishable from atmospheric noise, thereby minimizing interference with FM radio reception and meeting statutory and customer emission requirements.
Implementation Method 1
By configuring the clock generator (13) in such a way that the basic clock is modulated, it is achieved that the electromagnetic emissions of the switching converter (1) are optimized
Data Source
AI summary
A switching converter, including an input interface for providing an input voltage, an output interface for providing at least one output voltage, a voltage conversion device for converting the provided input voltage into one of the at least one output voltage, and a clock generator for providing a working clock, the clock generator being configured in such a way that the clock generator provides a modulated basic clock as the working clock. A control unit including such a switching converter, and a method for operating such a switching converter, are also described.