Switching Power Supply Adjustable Feedback Loop Bypass Mode

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Solution Overview

Problem

Switching power supplies face inefficiencies when operating below a certain power threshold, as traditional methods for transitioning to Bypass mode can cause current peaks that risk damaging components.

Innovation Solution

A switching power supply with a resistive feedback loop of adjustable value, capable of transitioning between states to maintain output voltage equal to or greater than the supply voltage, using transistors and resistors to control the feedback loop and duty cycle, ensuring a gradual voltage increase without peak currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods are used to transition to Bypass mode, then the power supply can operate in Bypass mode, but current peaks occur that risk damaging components

Engineering Contradiction:
Improvecomponent safetyVSAvoidcurrent peaks
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The feedback resistance is adjusted before transitioning to Bypass mode to pre-establish safe operating conditions. By modifying the feedback resistance value in advance, the output voltage is prepared to match the input voltage, preventing harmful current peaks when Bypass mode activates

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The feedback resistance value is dynamically changed during the transition process. The control circuit modifies the feedback resistance parameter to ensure the output voltage gradually approaches the input voltage level, eliminating current peaks and ensuring safe transition to Bypass mode

Inventive Principle:
Principle #35Parameter changes

2Use of energy by moving object

If the power supply operates below a certain power threshold, then efficiency decreases, but traditional transition methods cause component damage risk

Engineering Contradiction:
Improvepower supply efficiencyVSAvoidcomponent safety
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The feedback resistance parameter is dynamically adjusted based on the power threshold condition. When power drops below the threshold, the feedback resistance is modified to prepare for safe Bypass mode transition, enabling efficient low-power operation without compromising component safety

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The control circuit continuously monitors the power level and uses feedback to determine when to adjust the feedback resistance. This feedback mechanism ensures that the transition to Bypass mode occurs only when appropriate, maintaining both efficiency and reliability

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3557742B1Switching mode power supply
Publication Date: 2020.12.09 STMICROELECTRONICS (ALPS) SAS
  • EP3557742B1 patent drawingFigure 1
  • EP3557742B1 patent drawingFigure 2
  • EP3557742B1 patent drawingFigure 3~5

AI summary

The invention relates to a switching power supply (200) comprising a resistive feedback loop (R) of adjustable value.