DC Power Supply Current Stabilizing Circuit Noise Reduction

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Solution Overview

Problem

Existing DC power supply systems using long power-supply cables suffer from radiated noise due to switching operations, which conventional methods like ferrite beads or linear regulators either fail to adequately address or do so at the cost of efficiency or increased complexity.

Innovation Solution

A DC power supply device with a current stabilizing circuit connected in either the pre-stage or post-stage of a switching power supply, utilizing a low-pass filter and voltage-control circuitry to regulate current and reduce noise without significantly impacting efficiency or causing oscillation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If a ferrite bead is inserted in the power-supply cable to reduce radiated noise, then noise reduction is achieved to some extent, but the bead may not effectively restrain transmission of current fluctuations to the upstream and sufficient noise reduction is not contributed

Engineering Contradiction:

Improveradiated noiseVSAvoidnoise reduction effectiveness

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent introduces a current stabilizing circuit as an intermediary device between the switching power supply and the power-supply cable. This circuit acts as a mediator that smooths current fluctuations before they reach the cable, thereby reducing radiated noise more effectively than a ferrite bead alone. The stabilizing circuit includes capacitors and resistors that work together to filter current variations.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the approach from passive noise filtering (ferrite bead) to active current stabilization by modifying the electrical parameters of the power supply system. By adding capacitive elements and controlling the timing of power delivery, the system alters the current waveform to reduce high-frequency fluctuations that cause radiated noise.

Inventive Principle:

Principle #35Parameter changes

2Object-affected harmful factors

If a linear regulator is used in the upstream of a DC-DC converter to reduce radiated noise, then noise reduction is achieved, but efficiency greatly decreases and the regulator may oscillate

Engineering Contradiction:

Improveradiated noiseVSAvoidefficiency

Core Design Contradiction:

Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

Instead of using a static linear regulator that continuously dissipates power, the patent employs a dynamic switching power supply with controlled switching elements. The system dynamically adjusts the switching timing and duration to deliver power while minimizing current fluctuations. This dynamic approach maintains efficiency by only converting power when needed, rather than continuously regulating it through resistive dissipation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent uses periodic switching action to deliver power in controlled pulses rather than continuous flow. By switching the power supply on and off at optimized intervals and durations, the system reduces current fluctuations that cause radiated noise while maintaining high efficiency. The periodic switching allows the system to recover energy through inductors and capacitors rather than dissipating it continuously.

Inventive Principle:

Principle #19Periodic action

3Object-affected harmful factors

If shielding cables are used to reduce radiated noise, then noise reduction is achieved, but cost and weight increase

Engineering Contradiction:

Improveradiated noiseVSAvoidsystem weight

Core Design Contradiction:

Object-affected harmful factorsVSWeight of stationary object

Solution Approach 1:

The patent replaces the mechanical/physical shielding approach (metal shields, ferrite beads) with an electrical solution (current stabilizing circuit). Instead of physically blocking or absorbing electromagnetic radiation through additional materials, the system uses electrical components to prevent the generation of noise in the first place by stabilizing current flow at the source.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Effectively reduces radiated noise from power-supply lines by stabilizing current fluctuations, maintaining efficiency, and preventing regulator oscillation, while simplifying design and reducing electromagnetic interference.

Implementation Method 1

A switching power supply, and a current stabilizing circuit connected in a pre-stage or a post-stage of the switching power supply... convert the input DC voltage into a different DC voltage

Methodology Applied

Scientific EffectElectromagnetic Induction: Electromagnetic Induction

Implementation Method 2

utilizing a low-pass filter and voltage-control circuitry to regulate current and reduce noise

Methodology Applied

Scientific EffectLow-pass filtering: Filter (electronic)

Data Source

PatentUS11451141B2DC power supply device, current stabilizing circuit for DC power supply device, and method for reducing noise of power-supply line

Publication Date: 2022.09.20 MITSUMI ELECTRIC CO LTD

AI summary

A DC power supply device includes a switching power supply and a current stabilizing circuit connected in a pre-stage or a post-stage of the switching power supply. The DC power supply voltage device is configured to receive an input DC voltage from a DC power source via a power-supply line, convert the input DC voltage into a different DC voltage, and output the converted DC voltage.