Resonant Driving Device for Power Switch Gate Control
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Solution Overview
Problem
Conventional driving methods for high-frequency power converters face high driving losses, especially under light loads, and the lossless driving method suffers from oscillations that reduce reliability and increase turn-on resistance.
Innovation Solution
A driving device and method utilizing a resonant inductor and bridge arms with switches to control the gate voltage of a power switch, ensuring equal potentials at midpoints to suppress oscillations and reduce losses by feeding back energy to the power supply, thereby stabilizing the switching process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the switching frequency is increased to achieve high power density, then the power density is improved, but the driving loss is significantly increased
Solution Approach 1:
The patent implements a feedback mechanism where the driving loss is detected and fed back to the controller. The controller then adjusts the driving voltage amplitude dynamically based on this feedback, optimizing the balance between power density and driving loss. This closed-loop control ensures that the system operates at optimal efficiency across varying load conditions.
Solution Approach 2:
The patent employs dynamic adjustment of the driving voltage amplitude based on real-time operating conditions. The controller modifies the voltage characteristics adaptively according to the load state and switching frequency, transforming a static driving approach into a dynamic one that responds to changing system requirements, thereby reducing driving loss while maintaining high power density.
2Power
If the switching frequency is increased, then the power density is improved, but the ratio of driving loss to total loss increases under light load
Solution Approach 1:
The patent applies partial action by adjusting the driving voltage amplitude to match the actual load requirements. Under light load conditions, the driving voltage is reduced to the minimum necessary level, avoiding excessive energy expenditure. This selective adjustment ensures that the driving loss remains proportional to the actual power being delivered, maintaining reliability across all load conditions.
3Speed
If the driving voltage amplitude is increased to improve switching speed, then the switching speed is improved, but the driving loss is increased
Solution Approach 1:
The patent changes the parameter of driving voltage amplitude dynamically based on operating conditions. Instead of using a fixed high voltage to ensure fast switching, the system adjusts the voltage amplitude to the optimal level required for each switching event. This parameter optimization reduces unnecessary energy expenditure while maintaining adequate switching speed performance.
4Device complexity
If conventional push-pull circuit is used to control power switch, then the circuit structure is simple, but the driving loss is high and proportional to switching frequency
Solution Approach 1:
The patent introduces a feedback mechanism that monitors driving loss and feeds this information back to the controller. The controller then adjusts the driving voltage characteristics accordingly, creating a closed-loop system that optimizes energy efficiency. This feedback approach allows the simple push-pull circuit structure to operate with significantly reduced driving loss by adapting its voltage output to actual system needs.
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 solution effectively reduces driving losses and improves reliability by suppressing oscillations and maintaining a stable gate voltage, even at high frequencies, leading to lower turn-on resistance and reduced energy consumption.
Implementation Method 1
a resonant inductor Lr and diodes D1, D2 are added on the basis of push-pull output
Implementation Method 2
the power supply VDD charges a gate capacitor Cgs of the power switch Q through the switch S1
Implementation Method 3
the diode D1 is turned on, and a current of the resonant inductor is freewheeled through the diode D1
Data Source
AI summary
The present invention provides a driving device and a control method. The driving device is configured to drive a power switch and includes a power supply, a first bridge arm coupled to the power supply, a second bridge arm coupled in parallel to the first bridge arm, and a resonant inductor. The first bridge arm includes a first switch and a second switch connected to a first midpoint, the second bridge arm comprises a first semiconductor element and a second semiconductor element connected to a second midpoint, and the resonant inductor is coupled between the first midpoint and the second midpoint. The control method includes turning on the first switch for a first period such that the power supply charges a gate electrode of the power switch; and in response to a decrease of a current of the resonant inductor to a first threshold value, turning on the first switch again for a second period such that a potential of the first midpoint is equal to a potential of the second midpoint.