Dual-Gate IGBT Driver for Low-Loss Turn-Off Control
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Solution Overview
Problem
Existing insulated gate bipolar transistors (IGBTs) face high switching losses while maintaining low conduction losses, necessitating a driving device that can reduce switching losses without increasing conduction losses.
Innovation Solution
A driving device that controls a semiconductor element with a controller and driver, utilizing first and second gate electrodes, and adjusts output impedance based on switching rate to minimize switching losses through active driving and double gate driving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional driving is used for IGBT, then conduction loss is kept low, but switching loss becomes large
Solution Approach 1:
The gate control is segmented into two independent gate electrodes (first gate electrode and second gate electrode). The first gate electrode controls the main switching operation, while the second gate electrode specifically handles minority carrier extraction during turn-off. This segmentation allows independent optimization of conduction and switching characteristics without increasing overall device complexity.
Solution Approach 2:
The second gate electrode acts as an intermediary element that facilitates minority carrier extraction from the drift region during turn-off. By introducing this intermediate control mechanism, the patent achieves reduced switching loss without requiring fundamental changes to the main switching structure, thereby maintaining manageable device complexity.
2Loss of energy
If switching rate is increased to reduce switching loss, then switching loss decreases, but surge voltage and noise increase
Solution Approach 1:
The second gate electrode is activated in advance during the turn-off process to begin extracting minority carriers before the main switching operation completes. This preliminary action on the minority carrier extraction process allows the main switching to proceed at high speed while the second gate simultaneously prepares to mitigate surge voltage and noise, thus achieving both reduced switching loss and suppressed harmful factors.
Solution Approach 2:
The driving device monitors switching conditions and dynamically adjusts the drive waveforms for both gate electrodes. Based on detected switching state, the controller optimizes the timing and amplitude of signals applied to the first and second gate electrodes, enabling high-speed switching while providing feedback control to suppress surge voltage and noise generation.
Data Source
AI summary
An embodiment includes a controller and a driver. The controller controls to drive a semiconductor element having a first gate electrode and a second gate electrode base on a control signal. The driver outputs a first driving signal to the first gate electrode and a second driving signal to the second gate electrode. The first driving signal drives the first gate electrode at ON or OFF timing of the control signal. The second driving signal drives the second gate electrode a timing earlier than the OFF timing of the control signal. The driver switches output impedances corresponding to the switching speed of the semiconductor element.