Semiconductor Switch Gate Wiring for Independent Edge Control
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Solution Overview
Problem
Existing semiconductor switch circuits face challenges in managing voltage gradients during switching, leading to increased switching losses, reduced service life, and electromagnetic compatibility issues due to non-linear voltage switching edges, which are difficult to address in simple control circuits without compromising switching performance.
Innovation Solution
A circuit configuration that includes a capacitor between the gate and collector or drain, with a parallel resistor and diode connected in series, allowing independent adjustment of switch-on and switch-off behaviors by controlling the diode's orientation relative to the gate, thereby decoupling the capacitor's influence on both operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a capacitor is added between gate and collector to control voltage edges, then electromagnetic compatibility is improved, but switch-off overvoltage increases and switching losses increase
Solution Approach 1:
The patent segments the capacitor's influence on turn-on and turn-off operations by introducing a diode in series with the capacitor. This allows independent optimization: the capacitor controls voltage edges during turn-on for EMC compliance, while the diode prevents the capacitor from negatively affecting turn-off performance, thereby reducing switch-off overvoltage and switching losses.
2Object-affected harmful factors
If gate resistance is increased to limit maximum voltage rise rate, then electromagnetic compatibility is improved, but switching speed decreases and switching losses increase
Solution Approach 1:
The patent applies local quality by using the capacitor-diode network to specifically control the voltage rise rate during turn-on without affecting turn-off speed. The capacitor provides localized damping during turn-on to limit dv/dt for EMC compliance, while the diode ensures this capacitance does not slow down turn-off, allowing independent optimization of each switching event's characteristics.
3Device complexity
If a simple gate driver circuit is used, then device complexity is reduced, but independent control of turn-on and turn-off characteristics is not possible
Solution Approach 1:
The patent introduces a diode as an intermediary element between the gate driver and the capacitor. This simple addition enables independent control of turn-on and turn-off characteristics without requiring complex regulated current sources or sophisticated driver circuits. The diode acts as a mediator that directs capacitor current only during turn-on, achieving independent optimization while maintaining circuit simplicity.
4Object-affected harmful factors
If capacitor value is optimized for turn-on, then voltage edge control is improved, but turn-off performance deteriorates with higher overvoltage
Solution Approach 1:
The patent segments the capacitor's effect on switching operations by combining it with a series diode. This allows the capacitor to be optimized for turn-on voltage edge control (improving EMC) while the diode prevents the capacitor from influencing turn-off, thereby eliminating the trade-off and allowing independent optimization of both turn-on and turn-off characteristics without compromise.
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 reduces switch-off overvoltage, lowers switching losses, enhances electromagnetic compatibility, and enables a more compact converter design by allowing separate adjustment of maximum and average switching edges.
Implementation Method 1
arrange a capacitor C1 between the collector C and the gate G for this purpose. Voltage edges in the load circuit cause a displacement current via the capacitor C1, which is fed back to the gate G and charges or discharges it in such a way that it counteracts the switching edge (negative feedback)
Implementation Method 2
In series with the capacitor C1 there is provided a parallel circuit made up of a resistor R3 and a diode V2, the diode V2 being connected away from the gate G in the flow direction. The diode is connected in forward direction away from the gate. Thus, only the switch-on behavior of the semiconductor switch is influenced and/or improved
Data Source
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AI summary
The invention relates to a wiring (1) of a semiconductor switch (T1), comprising a gate (G), a collector (C) or a drain, and an emitter (E) or a source, wherein the wiring (1) comprises a capacitor (C1) between the gate (G) and the collector (C) or drain, and a parallel circuit of a resistor (R3) and a diode (V2) is provided in series with the capacitor (C1).