GaN Half Bridge Driver With Blanking Pulse Generator
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Solution Overview
Problem
Existing half bridge power conversion circuits using GaN devices face challenges in high-frequency and high-efficiency operations due to issues with false triggering and shoot-through conditions, which affect the reliability and efficiency of power conversion.
Innovation Solution
The implementation of a half bridge GaN circuit with integrated level shift circuits and bootstrap capacitor charging, which includes low side and high side switch drivers, level shift transistors, and a blanking pulse generator to prevent false triggering and shoot-through by controlling the switching transitions and voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If GaN devices are used for high-frequency operation, then switching speed is improved, but false triggering and shoot-through conditions occur reducing reliability
Solution Approach 1:
The blanking pulse generator produces a blanking pulse before and during the expected shoot-through period to preemptively prevent false triggering. This preliminary action blocks the gate driver output during the critical time window when shoot-through conditions could occur, allowing high-frequency operation without compromising reliability
Solution Approach 2:
The blanking pulse acts as an intermediary signal that mediates between the high-speed switching signals and the gate driver. By introducing this intermediate control signal, the system can maintain high switching speeds while the blanking pulse prevents harmful interactions that would reduce reliability
2Ease of operation
If level shift circuits are added to control voltage levels, then switching control is improved, but device complexity increases
Solution Approach 1:
The level shift circuits and blanking pulse generator are integrated into a single gate driver device, merging multiple functions (level shifting, blanking pulse generation, and gate driving) into one unified component. This integration improves switching control while minimizing the increase in overall device complexity by consolidating rather than adding separate components
Data Source
AI summary
A half bridge GaN circuit is disclosed. The circuit includes a low side circuit, which has a low side switch, a low side switch driver configured to drive the low side switch, a first level shift circuit configured to receive a first level shift signal, and a second level shift circuit configured to generate a second level shift signal. The half bridge GaN circuit also includes a high side circuit, which has a high side switch configured to be selectively conductive according to a voltage level of a received high side switch signal, and a high side switch driver configured to generate the high side switch signal in response to the level shift signals. A transition in the voltage of the high side switch signal causes the high side switch driver to prevent additional transitions of the voltage level of the high side switch signal for a period of time.