Flying Capacitor Charge Balancing in Step-Up Converters
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Solution Overview
Problem
Conventional step-up converters face challenges in maintaining the charging/discharging balance of flying capacitors, leading to unstable output voltages due to complex control logic and additional costs associated with feedback control.
Innovation Solution
A step-up converter design incorporating an inductor unit, power switch units with parallel flying capacitors, and a control unit that controls the charging and discharging of flying capacitors across multiple time intervals to achieve balanced voltage levels, allowing for easy management of the charging/discharging balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feedback control is used to maintain flying capacitor charging/discharging balance, then output voltage stability is improved, but control logic complexity and cost increase
Solution Approach 1:
The flying capacitor automatically maintains its charging/discharging balance through the inherent circuit structure and switching sequences, without requiring external feedback control. The circuit self-regulates by naturally equalizing charges between flying capacitors during specific switching intervals, eliminating the need for complex feedback control logic while maintaining output voltage stability.
2Reliability
If feedback control is used to maintain flying capacitor charging/discharging balance, then output voltage stability is improved, but cost increases
Solution Approach 1:
The circuit structure enables automatic charge balancing of flying capacitors through inherent switching operations, eliminating the need for additional feedback control circuits, sensors, and associated components. This self-balancing mechanism reduces component count and manufacturing cost while maintaining reliable output voltage stability.
3Adaptability or versatility
If multiple power switch units with flying capacitors are used to achieve voltage conversion, then voltage ratio flexibility is improved, but device complexity increases
Solution Approach 1:
The voltage conversion function is divided into multiple independent power switch units, each containing power switches and flying capacitors. Each unit can operate semi-independently to provide different voltage conversion ratios, enabling flexible voltage adjustment while maintaining modular circuit structure that simplifies analysis and control compared to monolithic designs.
Solution Approach 2:
Multiple power switch units with flying capacitors are combined in a unified circuit architecture where the flying capacitors serve dual purposes: voltage conversion and automatic charge balancing. This merging of functions reduces the need for separate balancing circuits and simplifies the overall system while maintaining voltage ratio flexibility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The proposed solution enables straightforward control of flying capacitor balance, stabilizing output voltages and reducing the complexity and cost associated with feedback control methods.
Implementation Method 1
a converter that increases an output voltage to be higher than an input voltage... In general, a step-up converter has a structure of building up current in an inductor in one time interval... and outputting the built-up current to a load
Implementation Method 2
A flying capacitor may be included in the step-up converter to change a voltage ratio of an input voltage and an output voltage. The step-up converter may increase or decrease the voltage ratio while charging or discharging the flying capacitor in each control period
Data Source
AI summary
An embodiment provides a technology of sharing electric charges of two or more flying capacitors in a time interval in which a plurality of flying capacitors are floated, so as to control the charging/discharging balance of the flying capacitors, in a step-up converter.