What is an IGBT? Simply Explained
The IGBT (Insulated Gate Bipolar Transistor) is a semiconductor device used in power electronics. It combines the advantages of two technologies: the easy control of a MOSFET with the high current capacity of a bipolar transistor.
🔧 How does an IGBT work?
An IGBT is a three-terminal switch (collector, emitter, gate). Its switching behavior is based on the combination of two semiconductor structures:
- ✅ The gate controls the current flow – just like a MOSFET.
- ✅ The main current flows through a bipolar (PNP) structure, allowing higher currents.
IGBTs can switch large loads with low gate power – ideal for high voltage and fast switching applications.
⚙️ Common applications of IGBTs
- Inverters: e.g. in solar and wind power systems
- Motor control: in industrial drives, elevators, and trains
- UPS systems: uninterruptible power supplies
- Welding & induction heating: precise power switching
- HVDC grids: high-voltage direct current transmission
📊 Comparison: IGBT vs. MOSFET
| Criterion | IGBT | MOSFET |
|---|---|---|
| Voltage range | 400 V to >1000 V | < 300 V typically |
| Switching frequency | Lower | Higher (MHz possible) |
| Switching losses | Slightly higher | Lower |
| Cost | Cheaper for high power | Better for low power |
✅ Advantages of IGBTs
- High voltage tolerance: ideal for medium and high voltages
- Low control effort: easy gate drive
- Robust & reliable: even under high current loads
- Great for low frequencies & high power switching
⚠️ Disadvantages & Limitations
- ❌ Slower than MOSFETs – not suitable for very high frequencies
- ❌ Higher switching losses in fast applications
- ❌ Temperature-sensitive – requires cooling under continuous load
🧠 Conclusion: When is an IGBT the right choice?
An IGBT is ideal when high voltage needs to be switched and moderate switching frequencies are sufficient – such as in drives, solar systems, or power supplies. It combines efficiency, switching performance, and controllability – perfect for modern power electronics.
❓ Frequently Asked Questions (FAQ)
▶️ What does IGBT stand for?
IGBT stands for “Insulated Gate Bipolar Transistor” – a component that switches high power efficiently.
▶️ When is an IGBT used?
When high voltages need to be switched, such as in motor control systems, inverters, or induction heating systems.
▶️ What is the difference between an IGBT and a MOSFET?
IGBTs handle higher voltages and are better for high-power applications. MOSFETs switch faster and are more efficient at lower voltages.
