Gate Driver With Switchable Voltage Gradients For Surge Suppression
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Solution Overview
Problem
Conventional gate driving technologies for switching elements in power converters are unable to set arbitrary voltage gradients for the rising and falling edges of the gate voltage, leading to difficulties in suppressing surge voltage and surge current, which deteriorates the quality of the power converter.
Innovation Solution
A gate driver is configured with multiple turn-on and turn-off current sources and switches that allow for switching the voltage gradient of the gate voltage between multiple levels during different periods of the rising and falling edges, enabling precise control of the gate voltage waveform.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If voltage is applied from a direct-current power supply via a resistor to control the gate of the switching element, then the gate voltage can be controlled, but the voltage gradient cannot be arbitrarily set, leading to inability to suppress surge voltage and surge current
Solution Approach 1:
The gate driver divides the gate voltage control into multiple segments using separate turn-on and turn-off circuits. Each circuit independently controls the charging and discharging of the gate parasitic capacitance, allowing separate optimization of rising edge and falling edge characteristics to suppress surge voltage and current.
Solution Approach 2:
The invention dynamically adjusts the voltage gradient by controlling the charging and discharging currents of the gate parasitic capacitance. By making the gate voltage change rate controllable rather than fixed, the system can adaptively suppress surge voltage and surge current while maintaining ease of operation.
2Device complexity
If a fixed resistor is used for gate driving, then the circuit is simple, but the voltage gradient for rising edge and falling edge cannot be adjusted, deteriorating power converter quality
Solution Approach 1:
The gate drive circuit is segmented into independent turn-on and turn-off control circuits. This segmentation allows each circuit to be optimized for its specific function (charging or discharging the gate capacitance), improving reliability through specialized control while keeping each segment relatively simple.
Solution Approach 2:
The invention changes the control parameter from fixed resistance value to controllable current magnitude. By using current sources with controllable magnitude instead of fixed resistors, the system achieves adjustable voltage gradients that improve power converter reliability without excessive complexity.
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 configuration effectively suppresses surge voltage and surge current, improving the switching efficiency and reducing switching losses in power converters.
Implementation Method 1
this gate driving controls charging and discharging of a parasitic capacitance of the switching element via the resistor
Data Source
AI summary
A gate driver for driving a switching element includes turn-on current sources, turn-on switches, turn-off current sources, and turn-off switches. The turn-on current sources switch a voltage gradient of a rising edge waveform of a gate voltage of the switching element between a plurality of levels when the switching element is turned on. The turn-on switches drive and control the turn-on current sources. The turn-off current sources switch a voltage gradient of a falling edge waveform of the gate voltage between a plurality of levels when the switching element is turned off. The turn-off switches drive and control the turn-off current sources.