Q16Basic Electrical Engineering
Question
Explain IGBT in detail with neat diagrams.
Answer
An Insulated Gate Bipolar Transistor (IGBT) is an advanced power semiconductor that combines the high-speed, voltage-controlled gate of a MOSFET with the high-current, low-saturation-voltage capability of a BJT.
The Insulated Gate Bipolar Transistor (IGBT) is a sophisticated three-terminal (Gate, Collector, Emitter) power semiconductor switch heavily used in modern power electronics, such as electric vehicle inverters, VFDs (Variable Frequency Drives), and UPS systems.
Construction & Working: It is essentially a monolithic hybrid device. At its input (the Gate), it features a Metal-Oxide-Semiconductor (MOS) structure, exactly like a power MOSFET. This means it is a voltage-controlled device requiring practically zero steady-state drive current, making the gate drive circuits extremely simple and efficient. However, at its output (Collector-Emitter), it possesses the structure of a PNP Bipolar Junction Transistor (BJT). This grants the IGBT the incredible ability to handle massive currents and high blocking voltages with a very low on-state voltage drop ().
By applying a positive voltage to the Gate relative to the Emitter, an inversion channel is formed, turning the device ON. Removing the voltage turns it OFF. It combines the best of both worlds: the easy drive of a MOSFET and the low conduction loss of a BJT.