Buck-boost converter delta-sigma modulator loss reduction

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Solution Overview

Problem

Conventional buck-boost converters for portable electronic devices face challenges in reducing output harmonics and switching/conduction losses, often requiring complex control circuits and additional components, which increase circuit area and cost.

Innovation Solution

A buck-boost converter using a delta-sigma modulator (DSM) with a mode controller and gate driver to determine operation modes, employing 1-bit or 1.5-bit digital signals to control switches and adjust sampling frequency, thereby reducing switching and conduction losses without complex control circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-generated harmful factors

If conventional buck-boost converters use complex control circuits and additional filters to reduce output harmonics and switching losses, then the harmful factors are reduced, but the device complexity and circuit area increase

Engineering Contradiction:

Improveoutput harmonics and switching lossesVSAvoidcontrol circuit complexity

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces complex analog control circuits with a digital delta-sigma modulator that uses digital signal processing to control the buck-boost converter. The modulator uses a digital filter and quantizer to generate switching signals, substituting traditional analog PWM controllers and reducing circuit complexity while maintaining harmonic suppression performance

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a delta-sigma modulator as an intermediary between the error amplifier and the switching circuit. This modulator acts as a mediator that processes the error signal through digital filtering and modulation, effectively reducing output harmonics without requiring additional analog filters or complex control logic

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-generated harmful factors

If conventional buck-boost converters use additional filters and regulators to eliminate output harmonics, then the harmful factors are reduced, but the device complexity and cost increase

Engineering Contradiction:

Improveoutput harmonicsVSAvoidadditional components

Core Design Contradiction:

Object-generated harmful factorsVSDevice complexity

Solution Approach 1:

The patent replaces physical analog filters with a digital filter implemented in the delta-sigma modulator. The digital filter uses software-based signal processing to reject harmonic frequencies, eliminating the need for additional inductors, capacitors, and analog filter circuits while achieving the same harmonic suppression effect

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters of the converter by using high-frequency switching controlled by the delta-sigma modulator. By modulating the switching frequency and duty cycle dynamically, the system achieves harmonic suppression through parameter modulation rather than through additional filtering components

Inventive Principle:

Principle #35Parameter changes

3Loss of energy

If conventional buck-boost converters minimize the number of switches to reduce switching and conduction losses, then energy loss is reduced, but output harmonic generation increases

Engineering Contradiction:

Improveswitching and conduction lossesVSAvoidharmonic generation

Core Design Contradiction:

Loss of energyVSObject-generated harmful factors

Solution Approach 1:

The delta-sigma modulator serves as an intermediary that decouples the relationship between switch count and harmonic generation. It processes the control signal to ensure that even with minimal switches, the output harmonics are suppressed through digital filtering and modulation techniques, allowing the system to maintain both low loss and low harmonic characteristics

Inventive Principle:

Principle #24Intermediary (Mediator)

4Productivity

If conventional converters use inverting buck-boost configuration to convert power, then power conversion is achieved, but the circuit area and cost increase due to additional inductors and capacitors

Engineering Contradiction:

Improvepower conversion capabilityVSAvoidcircuit area

Core Design Contradiction:

ProductivityVSArea of stationary object

Solution Approach 1:

The patent implements a universal buck-boost converter that can operate in both buck and boost modes using the same circuit topology and control mechanism. The delta-sigma modulator dynamically adjusts the switching patterns to achieve either voltage step-down or step-up, eliminating the need for separate inverting converter circuits and reducing overall circuit area

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10505448B2Buck-boost converter using delta-sigma modulator

Publication Date: 2019.12.10 ELECTRONICS & TELECOMM RES INST

AI summary

A buck-boost converter using a delta-sigma modulator (DSM) includes a buck-boost mode driving circuit configured to receive an input voltage and output an output voltage according to an operation mode, a mode controller configured to sense an output of the buck-boost mode driving circuit and determine the operation mode, and a gate driver configured to receive a mode determination signal for determining the operation mode from the mode controller and control switches included in the buck-boost mode driving circuit. Accordingly, output ripple characteristics thereof can be improved.