What is an IGBT?
IGBT is the acronym for "Insulated Gate Bipolar Transistor", and the Chinese name is "Insulated Gate Bipolar Transistor". By combining MOSFETs and bipolar transistors, IGBTs become power transistors that offer the advantages of both devices. There are two types of IGBTs: N-channel type and P-channel type. This article takes the current mainstream N-channel type as an example to introduce.
The circuit diagram symbol of N-channel IGBT and its equivalent circuit are as follows. Some equivalent circuit diagrams are more detailed, but here is a relatively simple schematic for ease of understanding. Including the structure, the actual product will be a bit more complicated. Details on the structure, etc. will be introduced in subsequent articles.
IGBT has three pins: gate, collector and emitter. The gate is the same as a MOSFET, and the collector and emitter are the same as a bipolar transistor. The IGBT controls the port through a voltage like the MOSFET. In the case of the N-channel type, when a positive voltage is applied to the gate of the emitter, the collector-emitter conducts and the collector current flows. We will introduce its working and driving method separately.
As mentioned earlier, IGBTs are transistors that combine the advantages of MOSFETs and bipolar transistors. MOSFETs have the advantages of high input impedance and fast switching speed because the gate is isolated, but the disadvantage is that the on-resistance is high at high voltages. Bipolar transistors have low on-resistance even at high voltages, but suffer from low input impedance and slow switching speeds. By compensating for the respective shortcomings of these two devices, the IGBT becomes a transistor with high input impedance, high switching speed*, and low on-resistance even under high voltage conditions.
*Switching speed is slower than MOSFET, but faster than bipolar transistor.
Power devices such as IGBTs and MOSFETs are used according to the use conditions and needs of the application products, and are used in different applications. For example, IGBTs are used in high-voltage applications and MOSFETs are used in low-voltage applications. The scope of application and application field of IGBT will be introduced in subsequent articles.
・IGBT is the abbreviation of "Insulated Gate Bipolar Transistor", and the Chinese name is "Insulated Gate Bipolar Transistor".
・IGBT is a power transistor that combines the advantages of both MOSFET and bipolar transistor.
・The basic features of IGBTs are high input impedance, high switching speed, and low on-resistance even under high voltage conditions.