Dynamic Peak Inductor Current Control for Boost Converters

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Solution Overview

Problem

Existing boost converters in portable devices statically limit peak inductor current, failing to adapt to changes in battery supply voltage and inductance, leading to inefficient power management and risk of 'brownout' events due to overloading or underutilization of battery power.

Innovation Solution

A dynamic peak current control system that monitors input power supply voltage, inductance, and other characteristics to calculate a target peak inductor current, allowing for adaptive peak inductor current limiting to maximize power delivery while preventing overload, using a combination of hard and soft limits to manage power consumption based on system conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If peak inductor current is statically limited, then power supply overload is prevented, but power delivery capability is reduced and battery life is shortened

Engineering Contradiction:
Improvepower supply overload preventionVSAvoidpower delivery capability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements dynamic peak inductor current limiting by continuously monitoring battery supply voltage and adjusting the peak current threshold accordingly. The controller modifies the peak inductor current limit based on real-time battery voltage conditions, transitioning from a static fixed threshold to a dynamic adaptive threshold that varies with battery state, thereby resolving the contradiction between preventing overload and maximizing power delivery capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the parameter of peak inductor current limit from a fixed value to a variable value that depends on battery supply voltage. By making the current limit parameter dynamic and adaptive to battery conditions, the system can prevent overload when battery voltage is low while allowing higher current and thus higher power delivery when battery voltage is sufficient, resolving the contradiction between reliability and productivity.

Inventive Principle:
Principle #35Parameter changes

2Power

If peak inductor current is increased to maximize power delivery, then audio loudness is improved, but risk of brownout events increases

Engineering Contradiction:
Improvepower delivery to audio amplifierVSAvoidbrownout event prevention
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent implements a feedback mechanism where the controller continuously monitors battery supply voltage and uses this information to adjust the peak inductor current limit. This closed-loop feedback system ensures that power delivery to the audio amplifier is maximized only when battery voltage is sufficient, and automatically reduces current limit when voltage drops, preventing brownout events while optimizing audio performance.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the peak inductor current threshold based on real-time battery voltage monitoring. When battery voltage is high, the system allows higher peak current for maximum power delivery and audio loudness. When battery voltage drops below thresholds, the system dynamically reduces the current limit to prevent brownout, thus resolving the contradiction between power delivery and reliability.

Inventive Principle:
Principle #15Dynamics

3Device complexity

If static current limiting is used, then system simplicity is maintained, but adaptability to battery conditions is reduced

Engineering Contradiction:
Improvecurrent control system complexityVSAvoidadaptability to battery voltage changes
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a self-service control mechanism where the boost converter system automatically monitors its own operating conditions (battery supply voltage) and self-adjusts the peak inductor current limit without external intervention. The controller uses built-in voltage monitoring and automatic threshold adjustment, making the system adaptive to battery conditions while maintaining relatively simple architecture through integrated self-regulation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system incorporates voltage monitoring feedback that automatically adjusts current limiting behavior based on battery conditions. This feedback mechanism provides adaptability to varying battery voltage and inductance conditions without requiring complex external control circuits, resolving the contradiction between system simplicity and adaptability.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3332472B1Adjusting peak inductor current to limit supply input current
Publication Date: 2020.07.29 CIRRUS LOGIC INT SEMICON LTD
  • EP3332472B1 patent drawingFigure 1~2B
  • EP3332472B1 patent drawingFigure 3
  • EP3332472B1 patent drawingFigure 4

AI summary

A method may include monitoring an input power supply, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating a target peak inductor current based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a target average current of the inductor during a switching cycle of the boost converter. A method may include monitoring an input power supply voltage, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating an average current of the inductor during a switching cycle of the boost converter based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a peak inductor current of the inductor.