Segmented Gate Switching Device for Power Conversion
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Solution Overview
Problem
Existing switching devices for power conversion, such as IGBTs, face challenges in reducing turn-off losses and improving controllability of the rate of temporal change in output voltage (dv/dt) during turn-on and turn-off operations, due to conduction and switching losses, and issues with parasitic capacitance and floating layers.
Innovation Solution
A switching device with a semiconductor structure featuring trench-type gate electrodes and a floating layer, where the interval between gate electrodes is optimized to reduce turn-off losses and enhance controllability of dv/dt, by independently driving the gate electrodes with signals having a time difference in drive timing, thereby controlling the channel formation and electron injection into the drift layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the interval between gate electrodes is reduced to improve switching speed, then dv/dt controllability deteriorates due to increased parasitic capacitance
Solution Approach 1:
The gate electrodes are segmented into multiple independent groups that can be controlled separately. By dividing the gate control into first and second gate electrodes with different timing, the invention reduces the effective parasitic capacitance impact on dv/dt while maintaining close spacing for high switching speed. The segmented control allows progressive channel formation and electron injection.
Solution Approach 2:
The invention applies dynamic control by using different drive timings for different gate electrode groups. The first and second gate electrodes are activated and deactivated at different times, creating a dynamic control scheme that optimizes both switching speed and dv/dt controllability. This dynamic approach allows the system to adapt the effective capacitance during the switching transition.
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 turn-off losses and improves controllability of the output voltage's rate of change, achieving a better trade-off between on-state voltage and turn-off loss, while maintaining high-speed switching performance and short-circuit tolerance.
Implementation Method 1
a feedback capacity of a gate insulating film that separates the gate from the floating layer
Implementation Method 2
the holes are accumulated in the drift layer during conduction so that the on-state voltage is reduced
Implementation Method 3
a set of gate electrodes including a first gate electrode and a second gate electrode provided to respectively abut two trenches with the semiconductor layer, the channel layer
Data Source
AI summary
The present invention provides a switching device (100) for power conversion in which a first gate electrode (6), a p-type channel layer (2) having an n-type emitter region (3), a second gate electrode (13), and a p-type floating layer (15) are repeatedly arranged in order on the surface side of an n-type semiconductor substrate (1). An interval a between the two gates (6, 13) that sandwich the p-type channel layer (2) is configured to be smaller than an interval b between the two gates (13, 6) that sandwich the p-type floating layer (15). The first gate electrode (6) and the second gate electrode (13) are both supplied with drive signals having a time difference in drive timing.