IGBT working principle diagram

IGBT single tube working principle

The IGBT tube is an on-off switch. It is a composite fully controlled voltage-driven power semiconductor device composed of BJT (bipolar triode) and MOS (insulated gate field effect transistor). It has the high input impedance and GTR of MOSFET. The two advantages of low conduction voltage drop. The IGBT tube relies on the voltage conversion of its gate-source to complete its work. When +12V (greater than 6V, generally 12V to 15V) is applied to the gate-source, the IGBT is turned on. No voltage is applied to the gate-source or the voltage is applied to the source. When the voltage is negative, the IGBT is turned off. The purpose of adding negative pressure is to ensure reliable shutdown.

The structure diagram of IGBT tube is as follows:

IGBT single tube structure diagram and circuit symbols

As shown in the figure, the IGBT tube has three terminals, namely G, D, and S. After voltage is applied to both ends of G and S, the internal electrons are transferred (characteristics of semiconductor materials, which is why semiconductor materials are used as power electronic switches). (The reason), originally there is a one-to-one correspondence between positive ions and negative ions, and the semiconductor material is neutral. However, after the voltage is applied, the electrons accumulate to one side under the action of the voltage, forming a conductive channel, because the electrons can conduct electricity. , becomes a conductor. If the voltage applied to both ends of GS is removed, the conductive channel in this layer will disappear, it will no longer conduct electricity, and it will become an insulator.

If a positive driving voltage is applied between the gate and emitter of the IGBT, the MOSFET turns on, so that the collector and base of the PNP transistor enter a low resistance state and the transistor turns on; if the gate and emitter of the IGBT When the voltage between the poles is 0V, the MOSFET turns off, cutting off the supply of base current to the PNP transistor, causing the transistor to turn off.

Working principle of IGBT module

IGBT single tubes are very popular in the field of DIY electrical components because they are relatively cheap. In industrial manufacturing R&D and high-power fields, IGBT modules integrating multiple IGBT tube switches are needed. The IGBT module is a combination of several units of IGBTs. For example, a 7-unit module is equivalent to seven single-tube IGBTs. This has the advantage of saving space. The packaged IGBT module can adapt to various harsh application environments and has a much wider range of uses than IGBT single tubes. However, their principles and functions are the same and they can be used as high-speed switches in circuits.

Fuji 7-unit module 7MBR30SA060 internal wiring diagram

Related reading: Fuji 7-unit module 7MBR30SA060 Chinese data parameters

Fuji 7MBR30SA06 contains a driver circuit: it has soft switching characteristics and can control dV/dt and surge voltage when IGBT switches. Driven by a single power supply, no reverse bias power supply is required. Prevent misleading communication. When turned off, the IGBT gate is grounded with low impedance to prevent noise, etc. from causing Vce to rise and cause false turn-on. The driving circuit of each IGBT sets the optimal driving conditions. Fuji 7MBR30SA06 contains various protection circuits: each IGBT has overcurrent protection (OC), load short circuit protection (SC), control power supply undervoltage protection (UV), and overheating protection (OH). Each IGBT chip has a temperature detection component, so when the chip is abnormally hot, it can implement (TjOH) protection at high speed. Fuji 7MBR30SA06 has a built-in alarm output function: when OH or lower arm OC, TjOH, UV and other protection actions occur, the system is stopped by outputting an abnormal signal to the microcomputer that controls the IPM.