Buck-Boost Regulator Pass-Through Window Control

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Solution Overview

Problem

Conventional buck-boost regulators face inefficiencies and electromagnetic interference (EMI) issues due to continuous switching, limited current/power dissipation, and uncontrolled inductor current, especially in pass-through regions, which affects their performance in automotive and industrial applications.

Innovation Solution

A controller for buck-boost regulators that operates in different modes based on input voltage levels, allowing the output voltage to be regulated within a window, passing through input voltage when within a predetermined range, and actively switching to limit inductor voltage and current, thereby reducing switching losses and EMI.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If continuous switching is used in buck-boost regulator, then output voltage regulation is maintained, but efficiency degrades and EMI increases

Engineering Contradiction:

Improveoutput voltage regulationVSAvoidswitching losses

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements dynamic operating modes that adapt to input voltage conditions. The controller dynamically switches between pass-through mode (when VIN is within the window) and active regulation mode (when VIN is outside the window), optimizing efficiency across different operating conditions while maintaining output voltage regulation when needed.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the operational parameters of the buck-boost regulator by introducing a pass-through window voltage range. Within this window, the regulator operates differently (passing input voltage directly) compared to outside the window (active regulation), thereby reducing switching losses in the pass-through region while maintaining regulation capability when required.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If continuous switching is used in buck-boost regulator, then output voltage regulation is maintained, but EMI increases

Engineering Contradiction:

Improveoutput voltage regulationVSAvoidEMI

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The controller dynamically adjusts the switching behavior based on input voltage. When VIN falls within the pass-through window, the regulator minimizes switching activity, thereby reducing EMI generation. When VIN is outside the window, active switching resumes to maintain proper output voltage regulation, balancing EMI reduction with regulation requirements.

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If pass-through mode is implemented, then efficiency is improved, but inductor current becomes uncontrolled

Engineering Contradiction:

Improveswitching lossesVSAvoidinductor current control

Core Design Contradiction:

Loss of energyVSReliability

Solution Approach 1:

The patent incorporates feedback mechanisms through window comparator circuitry that continuously monitors input voltage levels. This feedback controls the transition between pass-through and active regulation modes, ensuring that pass-through operation only occurs when VIN is within the predetermined window, thereby preventing uncontrolled inductor current conditions.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent changes the control parameters by defining a specific voltage window range. Within this window, the regulator allows pass-through operation with relaxed current control; outside this window, it transitions to active regulation mode with full current control, optimizing efficiency while maintaining reliability.

Inventive Principle:

Principle #35Parameter changes

4Adaptability or versatility

If window regulation is used, then adaptability to input voltage range is improved, but device complexity increases

Engineering Contradiction:

Improveinput voltage rangeVSAvoidcontrol circuitry

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a universal control architecture that handles multiple operating modes (pass-through, buck, boost, and active regulation) within a single integrated controller. This multi-functional approach allows the regulator to adapt to various input voltage conditions while avoiding the need for separate control circuits for each mode, thereby reducing overall device complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10135340B1Pass through regulation of buck-boost regulator

Publication Date: 2018.11.20 ANALOG DEVICES INT UNLTD CO

AI summary

A controller may control a buck-boost regulator having an input voltage and an output voltage. The controller may include: circuitry that causes the output voltage of the buck-boost regulator to be at the bottom of a pre-determined voltage window when the input voltage goes below the bottom of the pre-determined voltage window: circuitry that causes the output voltage of the buck-boost regulator to be at the top of the pre-determined voltage window when the input voltage goes above the top of the pre-determined voltage window; and circuitry that causes the buck-boost regulator to pass the input voltage through the buck-boost regulator so as to cause the voltage output of the buck-boost regulator to be at the same level as the input voltage when the input voltage is within the pre-determined voltage window.