Half-bridge circuit using monolithic FLIP-chip GAN power devices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current half bridge power conversion circuits using GaN devices face challenges in efficiently converting high DC voltage to lower DC voltage while minimizing size and maximizing efficiency, particularly in high-frequency operations, due to issues with shoot-through prevention and voltage handling.
Innovation Solution
A half bridge circuit design incorporating low side and high side GaN-based circuits with integrated level shifters, shoot-through protection, and bootstrap capacitor charging, utilizing GaN-based enhancement-mode transistors and depletion-mode transistors to manage voltage and prevent simultaneous conduction of switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If GaN devices are used in half bridge circuits for high-frequency operation, then conversion efficiency is improved, but shoot-through prevention becomes more difficult
Solution Approach 1:
The patent implements dead-time control that preemptively prevents shoot-through by controlling the timing of switch transitions. The control circuit introduces a deliberate time delay between turning off one switch and turning on the other, ensuring that both switches are never simultaneously conducting. This preliminary action resolves the contradiction by maintaining high-frequency efficient operation while preventing shoot-through conditions through proactive timing control.
Solution Approach 2:
The patent employs feedback mechanisms through control circuits that monitor the state of GaN devices and adjust switching timing accordingly. The control system continuously observes voltage and current conditions, and dynamically adjusts the dead-time intervals to prevent shoot-through while maximizing conversion efficiency. This feedback loop ensures reliable operation at high frequencies by adapting to real-time circuit conditions.
2Power
If high DC voltage is converted to lower DC voltage using half bridge converter, then power conversion capability is improved, but circuit complexity increases
Solution Approach 1:
The patent integrates multiple functions into unified control circuits that simultaneously manage voltage conversion, dead-time control, and shoot-through prevention. By merging these previously separate control functions into a single integrated control system, the patent achieves high power conversion capability while reducing overall circuit complexity. The integrated controller handles multiple tasks that would otherwise require separate discrete components.
Solution Approach 2:
The control circuits designed in the patent serve multiple functions: they regulate voltage conversion, implement dead-time control, prevent shoot-through conditions, and adapt to varying load conditions. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby achieving robust power conversion capability with reduced circuit complexity compared to traditional approaches requiring separate control modules for each function.
Data Source
AI summary
GaN-based half bridge power conversion circuits employ control, support and logic functions that are monolithically integrated on the same devices as the power transistors. In some embodiments a low side GaN device communicates through one or more level shift circuits with a high side GaN device. Various embodiments of level shift circuits and their inventive aspects are disclosed.