Hybrid Buck-Boost Converter Using Flying Capacitor Current Bypass
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Solution Overview
Problem
Traditional buck-boost converters suffer from high inductor current and conduction losses, limited maximum voltage step-up ratio, and inefficiency in powering OLED displays and VCSELs, which are inadequate for modern smartphone and mobile computing applications.
Innovation Solution
A hybrid non-inverting buck-boost converter with a flying capacitor and a network of switches that allows for reduced inductor current by bypassing the inductor in certain operational states, enabling improved boost conversion efficiency and extended maximum voltage boost ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If traditional pure inductive buck-boost converters are used, then voltage conversion is achieved, but large inductor footprint and height dominate the solution area
Solution Approach 1:
The patent segments the current path by introducing a flying capacitor that creates alternative current routes. The converter operates in multiple modes (buck, boost, bypass) where current can flow through different paths including direct capacitor coupling that bypasses the inductor, thereby reducing the required inductor size and overall footprint.
Solution Approach 2:
The flying capacitor acts as an intermediary element that enables direct energy transfer between input and output without requiring large inductor currents. The capacitor mediates the power transfer in bypass mode, allowing the inductor to be smaller since it doesn't need to handle the full output current.
2Loss of energy
If traditional buck-boost converters are used, then voltage conversion is achieved, but high inductor current and conduction losses occur
Solution Approach 1:
The patent implements dynamic operation by switching between three distinct modes (buck, boost, bypass) based on the voltage conversion ratio requirements. The converter dynamically adjusts the current path and operational mode to minimize inductor current and conduction losses for each specific operating condition, rather than always operating with high inductor current.
Solution Approach 2:
The patent extracts the inductor from the mandatory current path by introducing the flying capacitor as an alternative energy storage and transfer element. In bypass mode, the inductor is completely bypassed and carries no current, eliminating its conduction losses entirely for that operating mode.
3Adaptability or versatility
If traditional buck-boost converters are used, then basic voltage conversion is achieved, but limited maximum voltage step-up ratio is obtained
Solution Approach 1:
The patent creates a multi-functional converter that can operate as a buck converter, boost converter, or bypass converter depending on the voltage conversion ratio requirements. This universal design allows the converter to achieve a wide range of voltage step-up ratios (from 0.5 to 2.0 and beyond) while maintaining high efficiency in each operating mode by using the optimal current path for each condition.
4Stability of the object's composition
If traditional buck-boost converters are used, then power conversion is achieved, but high ripple current and voltage occur
Solution Approach 1:
The patent merges multiple current paths and operational modes into a single unified converter architecture. By combining the buck path, boost path, and bypass path with the flying capacitor, the converter achieves smoothed current and voltage waveforms across all operating conditions, reducing ripple while maintaining reliable power supply quality for sensitive loads.
Data Source
AI summary
A buck-boost power converter is operable in a first mode (step-down) or in a second mode (step-up). The power converter has an inductor, a flying capacitor, a network of six switches and a driver adapted to drive the network of switches with a sequence of states. Depending on the mode of operation the sequence of states comprises at least one of a first state and a second state. In the first state the ground port is coupled to the second port via two paths, a first path comprising the flying capacitor and the inductor, and a second path comprising the flying capacitor while bypassing the inductor. In the second state the first port is coupled to the second port via a path that includes the inductor and the ground port is coupled to the first port via a path that includes the flying capacitor while bypassing the inductor.