Triode,also known as bipolar transistor, crystal triode, is a semiconductor device that controls current. Its function is to amplify the weak signal into an electrical signal with a larger amplitude value, and it is also used as a non-contact switch.
The triode is made on a semiconductor substrate with two PN junctions that are very close to each other. The two PN junctions divide the whole semiconductor into three parts. The middle part is the base area, and the two sides are the emitter area and the collector area. The arrangement is PNP And NPN two kinds.
Triode
Due to the structural and characteristic limitations of the triode, it is not suitable for high-frequency circuits and high-speed switching circuits.
MOSFET（Metal-Oxide-Semiconductor Field-Effect Transistor）: MOSFET is a field-effect transistor that uses the effect of electric field to control the semiconductor (S) with the gate of the metal layer (M) separated by the oxide layer (O). Its characteristic is to use the gate voltage to control the drain current.
MOSFET has the advantages of high input resistance, low power consumption and fast switching speed, and is suitable for digital circuits, analog circuits, microprocessors and other fields, especially in power electronics, MOSFET can withstand a certain current and voltage, so it is also Widely used in switching power supplies, inverters and DC-DC converters and other fields.
MOSFET
The difference between a triode and a MOSFET is that the MOS tube is a unipolar tube while the triode is a bipolar tube. The unipolar and bipolar are distinguished from the type of carriers inside the semiconductor, so the unipolar is One type of carrier whereas bipolar is two types of carriers.
The more types of carriers, the greater the mutual hindrance, so the impedance of unipolar tubes will be much smaller than that of bipolar tubes, that is, the output current can be much larger, and at the same time, more current is allowed to pass through, allowing greater Voltage.So MOSFET can withstand more power than triode.
Advantages and disadvantages of MOSFET: high switching frequency and fast switching speed. The disadvantages are high on-resistance and high power consumption at high voltage, generally lower than 250V.
The MOSFET market is mainly occupied by Infineon. According to the IHS statistics, Infineon accounts for up to 27% of the market. The second place is Onsemi, accounting for 13% of the market, and the third place is Renesas, accounting for 9%. In the field of high-voltage MOSFET with high value content, Infineon is significantly ahead of all competitors with a market share of 36%, while Italian French Semiconductor and Toshiba are ranked second and third with a market share of 19% and 11% respectively.
IGBT (Insulated Gate Bipolar Transistor): IGBT is a fully controlled-voltage-driven power semiconductor composed of BJT (bipolar transistor) and MOSFET (insulated gate field effect transistor), mainly used in automobiles, Applications with relatively complex structures such as inverters and rail transit. It is mainly used in frequency conversion inverters and other inverter circuits(which can invert DC voltage into frequency-adjustable AC power.). It is called "the CPU of power electronic devices".
IGBT
IGBT has the advantages of both high input impedance of MOSFET and low on-resistance of BJT. However, with the addition of triode, the switch has some delay, trailing and slow speed. The advantage is that the on-resistance is low at high voltage.
IGBT has small driving power, which is very suitable for the converter system with DC voltage of 600V and above, such as AC motor, frequency converter, switching power supply, lighting circuit, traction drive, etc. In the IGBT market, Infineon, Mitsubishi and Fuji Electric are in the leading position, while Ansemy focuses on the low-voltage consumer electronics industry, with the voltage below 600V. The medium and high voltage fields above 1700V are mainly used in high-speed rail, automotive electronics, smart grid, etc., which are basically monopolized by Infineon, ABB and Mitsubishi.
To sum up, these three components have their unique advantages and application ranges, and which component to choose should be selected according to specific application requirements and circuit design.
