Multi-channel Power Supply Noise Reduction via Dynamic Frequency Control
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Solution Overview
Problem
Multi-channel power supply circuits with parallel switching circuits experience significant conducted noise due to constant switching frequencies, leading to malfunctions in other electronic devices, and existing noise reduction methods like capacitors or filters increase costs and space requirements, while frequency-changing techniques limit noise reduction effectiveness in advanced driving systems.
Innovation Solution
A power supply device with a transition management unit and clock generation unit that generates different clock signals for each switching circuit, using delay units to control switching signals based on calculated input current variations to minimize conducted noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a large-capacity capacitor is inserted into the input portion of the power supply circuit to reduce conducted noise, then the noise level is reduced, but the cost and mounting area increase
Solution Approach 1:
The invention changes the switching frequency parameter of the switching circuits over time using a frequency change pattern, transforming the noise characteristics from concentrated high-amplitude spikes at constant frequency to spread-out lower-amplitude noise across multiple frequencies, thereby reducing conducted noise without requiring large capacitors or filters
Solution Approach 2:
The invention implements periodic frequency changes by repeatedly outputting a frequency change pattern that includes multiple frequency values, causing the switching circuits to alternately operate at different frequencies in a periodic manner, which spreads the noise spectrum and reduces peak noise levels
2Device complexity
If switching control is performed at the same and constant switching frequency for each switching circuit, then the control is simple, but large conducted noise occurs due to the same frequency
Solution Approach 1:
The invention transitions from static constant frequency control to dynamic frequency control by introducing a frequency change pattern that varies the switching frequency over time, making the frequency parameter dynamic while maintaining relatively simple control logic through pattern repetition
Solution Approach 2:
The invention applies preliminary frequency modulation by pre-defining a frequency change pattern that is output to the switching circuits before noise problems occur, proactively spreading the noise spectrum rather than reacting to noise issues
3Adaptability or versatility
If the frequency of an oscillator is continuously changed to change the switching frequency parameter, then the switching frequency can be varied, but the frequency range is limited and noise reduction effect is insufficient
Solution Approach 1:
The invention segments the frequency variation into discrete frequency values within a pattern rather than continuous change, allowing multiple distinct frequency points to be utilized while maintaining effective noise spreading across a broader spectrum
Solution Approach 2:
The invention uses feedback by detecting the input current of the power supply circuit and adjusting the frequency change pattern accordingly, creating a closed-loop control system that optimizes noise reduction while expanding the effective frequency range
Data Source
AI summary
The present invention reduces conducted noise of an input current in a power supply device having a plurality of channels at low cost. In a power supply circuit (210) possessed by an autonomous running control ECU, switching circuits 22 respectively generate, on the basis of control signals C, power supplies supplied to a plurality of logic circuits. A transition management unit 25 controls the switching circuits 22. A clock generation unit 26 generates a plurality of clock signals. The transition management unit 25 has a control signal generation unit and a plurality of delay units. The control signal generation unit generates intermediate control signals from the clock signals generated by the clock generation unit 26. The delay units delay the intermediate control signals on the basis of command signals and output the delayed intermediate control signals as the control signals C. The clock signals generated by the clock generation unit include at least one clock signal having a different frequency.