Modified Buck Converter Topology for Voltage Step-Up

Solution Overview

Problem

Conventional boost converters face stability issues during continuous conduction mode and require high-current switches due to high current through the switch being much higher than the load current, making them unsuitable for high current/heavy load applications.

Innovation Solution

A modified buck topology converter with a floating voltage source is used, which includes a switching circuit receiving driving signals and a filter to generate an output voltage directly proportional to the duty cycle, reducing the current through switches and improving stability by using a half-bridge configuration with high and low side switches and a diode to provide an offset voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a conventional boost converter is used, then voltage step-up is achieved, but the current through the switch becomes much higher than the load current, requiring high-current switches and causing stability problems in continuous conduction mode

Engineering Contradiction:

Improvevoltage step-up capabilityVSAvoidstability in continuous conduction mode

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent inverts the conventional boost converter topology by using a buck converter configuration that achieves voltage step-up instead of the traditional boost approach. The modified buck converter with floating voltage source and specific switching sequence (high-side switch first, then low-side switch) produces an output voltage that is directly proportional to the duty cycle, achieving voltage multiplication while keeping switch currents equal to load current, thereby resolving the stability issue in continuous conduction mode

Inventive Principle:

Principle #13The other way round (Inversion)

2Power

If a conventional boost converter is used, then voltage step-up is achieved, but high-current switches are required due to high current through the switch

Engineering Contradiction:

Improvevoltage step-up capabilityVSAvoidswitch current requirements

Core Design Contradiction:

PowerVSDevice complexity

Solution Approach 1:

The patent inverts the conventional boost converter topology by using a buck converter configuration that achieves voltage step-up instead of the traditional boost approach. The modified buck converter with floating voltage source and specific switching sequence (high-side switch first, then low-side switch) produces an output voltage that is directly proportional to the duty cycle, achieving voltage multiplication while keeping switch currents equal to load current, thereby resolving the stability issue in continuous conduction mode

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS7659702B2Buck topology allowing step-up and polarity change

Publication Date: 2010.02.09 O2 MICRO INT LTD

AI summary

A buck topology that provides voltage step up and polarity change is disclosed. In one embodiment a converter includes an input for receiving an input voltage, a switching circuit coupled to the input for receiving a first driving signal, a floating voltage source coupled to the switching circuit for producing an offset voltage, and an output coupled to the floating voltage source for generating an output voltage. The output voltage exhibits a voltage level that is directly proportional to a duty cycle of the first driving signal.