Resonant Gate Drivers Eliminate Bootstrap Circuits
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Solution Overview
Problem
Existing half-bridge gate driver systems for switched-mode power supplies face challenges in efficiently controlling high side switches due to the need for bootstrap capacitors and additional level shifting circuits, which increase complexity and power dissipation.
Innovation Solution
A resonant gate driver system that magnetically couples a low side inductor to a high side inductor, eliminating the need for bootstrap diodes and level shifting circuits by using transferred energy to charge the high side gate driver and control the high side switching device directly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bootstrap capacitors and level shifting circuits are used to control high side switches, then the high side switch can be properly driven, but the device complexity increases
Solution Approach 1:
The patent extracts and eliminates the bootstrap capacitor and level shifting circuit from the traditional half-bridge gate driver configuration. By using a full-bridge topology with four gate drivers all referenced to a common ground, the circuit removes the floating power supply requirement for the high side driver, thereby simplifying the overall device complexity while maintaining reliable high side switch control.
2Reliability
If bootstrap capacitors and level shifting circuits are used to control high side switches, then the high side switch can be properly driven, but the power dissipation increases
Solution Approach 1:
The patent removes the bootstrap capacitor charging/discharging cycle and level shifting operations that consume significant power. By implementing a ground-referenced full-bridge gate driver system, the circuit eliminates the continuous power loss associated with bootstrap circuit operation, thereby reducing overall power dissipation while maintaining proper high side switch driving capability.
3Ease of operation
If additional level shifting circuits are used to activate the high side switch driver, then ground referenced logic signals can be used, but the device complexity increases
Solution Approach 1:
The patent implements a universal ground-referenced interface for all four gate drivers in the full-bridge configuration. Each gate driver receives ground-referenced logic signals directly without requiring individual level shifting circuits, as all drivers share a common ground reference. This multi-functional approach simplifies the interface design while maintaining ease of operation with standard logic signals.
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
This approach simplifies the control of high side switches, reduces power dissipation, and enhances efficiency by eliminating the need for bootstrap capacitors and additional level shifting circuits, thereby improving the overall performance of switched-mode power supplies.
Implementation Method 1
the second inductor is magnetically coupled to the first inductor
Data Source
AI summary
In accordance with an embodiment, a method of controlling a switch driver includes energizing a first inductor in a first direction with a first energy; transferring the first energy from the first inductor to a second inductor, wherein the second inductor is coupled between a second switch-driving terminal of the switch driver and a second internal node, and the second inductor is magnetically coupled to the first inductor; asserting a first turn-on signal at the second switch-driving terminal using the transferred first energy; energizing the first inductor in a second direction opposite the first direction with a second energy after asserting the first turn-on signal at the second switch-driving terminal; transferring the second energy from the first inductor to the second inductor; and asserting a first turn-off signal at the second switch-driving terminal using the transferred second energy.