Gate Driving Circuit with Reactor Current Control
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Solution Overview
Problem
Conventional gate driving circuits for semiconductor switching devices face challenges in reducing both switching loss and electromagnetic noise, particularly due to the trade-off between high-speed switching and noise reduction, and require complex and expensive high-speed operating elements and sensors for precise timing control.
Innovation Solution
A gate driving circuit with a variable current carrying path that includes a DC power source, a reactor, and a driving target device, operating in hold, preparation, and execution modes, where the reactor current flows through the reactor before turn-on or turn-off, allowing a resonant circuit to maintain a consistent gate current, thereby reducing switching loss and noise while simplifying control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the gate resistor is made small to achieve high-speed switching, then switching loss is reduced, but electromagnetic noise is increased
Solution Approach 1:
The reactor current is preliminarily increased to a necessary magnitude before the turn-on or turn-off operation. This preliminary action ensures that when the resonant circuit is formed, the gate current immediately reaches the required level without gradual increase, enabling both fast switching and noise reduction
Solution Approach 2:
The invention utilizes resonant vibration in the LC resonant circuit formed by the reactor and gate parasitic capacitance. By making the reactor and parasitic capacitance form a resonant circuit, the gate current flows through the resonant circuit and does not quickly change, reducing electromagnetic noise while maintaining switching performance
2Measurement precision
If a high speed operating element and high accuracy sensor are used to switch gate resistance value, then switching control precision is improved, but device complexity and cost are increased
Solution Approach 1:
The reactor current is preliminarily increased to a necessary magnitude before the turn-on or turn-off operation. This preliminary action ensures that when the resonant circuit is formed, the gate current immediately reaches the required level without gradual increase, enabling both fast switching and noise reduction
Solution Approach 2:
The reactor current flows continuously through the reactor before turn-on or turn-off, and then continues to flow through the resonant circuit during switching. This continuous current flow eliminates the need for high-speed switching of the gate resistor, simplifying the device while maintaining precise control
3Object-generated harmful factors
If the gate resistor is made large to reduce noise, then electromagnetic noise is reduced, but switching loss is increased
Solution Approach 1:
The reactor current is preliminarily increased to a necessary magnitude before the turn-on or turn-off operation. This preliminary action ensures that when the resonant circuit is formed, the gate current immediately reaches the required level without gradual increase, enabling both fast switching and noise reduction
Solution Approach 2:
The invention utilizes resonant vibration in the LC resonant circuit formed by the reactor and gate parasitic capacitance. By making the reactor and parasitic capacitance form a resonant circuit, the gate current flows through the resonant circuit and does not quickly change, reducing electromagnetic noise while maintaining switching performance
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 enables compatible reduction of switching loss and noise, ensures sufficient reactor current for subsequent operations, and improves the durability and reliability of the driving target device by avoiding excessive gate voltage, thus facilitating easier control and efficient high-speed switching.
Implementation Method 1
the reactor 105 and parasitic capacitance of the gate of the driving target device SW form a resonant circuit. Thus, the gate current Ig is not gradually increased after turn-on or turn-off, but the gate current Ig equal to the reactor current Ir flows at the same time as the turn-on or turn-off
Data Source
AI summary
A gate driving circuit has a variable current carrying path that switches a current carrying path among a driving target device, a DC power source and a reactor to operate in plural operation modes including at least a hold mode, a preparation mode, and an execution mode. The variable current carrying path includes a backflow path for causing a reactor current flowing through the reactor to flow back to the DC power source when a gate voltage of the driving target device deviates from a preset allowable voltage range. A drive control part sets the operation mode of the variable current carrying path to the hold mode and holds the ON state or the OFF state of the driving target device, and further switches the operation mode in sequence of the preparation mode and the execution mode, and realizes turn-on or turn-off of the driving target device.