Semiconductor Device Ringing Suppression via Inductive Current Damping
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Solution Overview
Problem
Existing semiconductor devices with SiC Schottky barrier diodes (SBD) experience ringing issues due to high di/dt and wiring inductance, which are not sufficiently suppressed by parallel connection with Si-PiN diodes, leading to increased switching losses and noise.
Innovation Solution
A semiconductor device configuration where at least one SBD is connected in series with a PiN diode and an output electrode, with the PiN diode's anode connected to the output electrode via the SBD's anode, increasing the inductance between the PiN diode and the output electrode, thereby prolonging the fall time of the forward current and suppressing ringing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the carrier frequency is increased to reduce reactor size, then the reactor can be made smaller, but the switching loss in the diode increases
Solution Approach 1:
The patent changes the material parameter of the diode from silicon (Si) to silicon carbide (SiC), which has superior switching characteristics including lower reverse recovery charge. This material substitution enables the system to operate at higher carrier frequencies with reduced switching losses, thereby allowing reactor size reduction without the penalty of excessive switching loss.
2Loss of energy
If SiC-SBD is used to reduce switching loss, then switching loss can be reduced, but di/dt increases and ringing occurs
Solution Approach 1:
The patent introduces a Si-PiN diode as an intermediary element connected in parallel with the SiC-SBD. The PiN diode has high reverse recovery charge characteristics that generate a current opposite to the SiC-SBD's recovery current. This intermediary component acts as a current buffer that suppresses the high di/dt and ringing generated by the SiC-SBD, while allowing the SiC-SBD to maintain its low switching loss advantage.
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 configuration effectively suppresses ringing and reduces switching losses by ensuring a longer fall time of the PiN diode's forward current compared to the SBD, enhancing noise reduction and device performance.
Implementation Method 1
an inductance between the PND and the output electrode is larger than an inductance between the SBD and the output electrode
Implementation Method 2
the recovery current serves as a dumper suppressing the noise caused by resonance
Data Source
AI summary
An object of the present invention is to provide a semiconductor device suppressing a ringing. A semiconductor device in an embodiment 1 includes an IGBT, an SBD connected to the IGBT in series, a PND connected to the IGBT in series and parallelly connected to the SBD, and an output electrode connected between the IGBT and the SBD and between the IGBT and the PND. An anode electrode of the PND is connected to the output electrode by the wiring via an anode electrode of the SBD.