This article introduces the "Si transistor" (the reason why Si is added in front of it because there are other transistors, such as SiC).
Although they are collectively referred to as "Si transistors," they can be classified into "bipolar" and "MOSFET" according to manufacturing processes and structures. In addition, it can be classified according to the current, voltage, and application of the processing.
The following topics are based on "power components", and power components are selected from a variety of transistors to illustrate them. Among them, MOSFETs widely used in applications that control high power in recent years will be developed.
First look at the transistor classification and characteristics.
Si transistor classification
Classification of Si Transistors According to different classification angles, there are several different classification methods. Here, roughly classified as follows from the aspects of structure and process. Among them, the theme of this article "power class" bold / coloring.
In bipolar transistors and MOSFETs, power-divided and small-signal types, IGBTs were originally developed for the processing of large power transistors, and therefore basically only power types.
Incidentally, MOSFET is an abbreviation for Metal Oxide Semiconductor Field Effect Transistor and is a kind of field effect transistor (FET). IGBT is an abbreviation for Insulated Gate Bipolar Transistor.
Si transistor characteristics
The following is a summary of the characteristics of the main evaluation items relative to transistors for bipolar transistors, MOSFETs, and IGBTs.
The evaluation of each item is based on the characteristics of the representative, so there is something that does not match. Please understand the overall tendency and characteristics. In addition, the structure, working principle, and representative parameters of these transistors are as follows.
A bipolar transistor (NPN in the figure) is composed of a PN junction. By passing a current through the base, a current flows between the collector and the emitter. As shown in the previous feature summary table, regarding the driving, it is necessary to adjust the base current and the like according to the relationship with the amplification factor and the collector current. Unlike MOSFETs, bias currents for amplification or on/off flow through the transistor (base).
In addition, there is a parameter called "on-resistance" in the MOSFET, which is an important characteristic especially when dealing with high power. However, there is no "on-resistance" parameter in bipolar transistors. The earliest transistors in the world are bipolar transistors, so it may be said that the order of expression is reversed. However, in recent years, MOSFETs in the power supply circuit are the mainstream, and many people may use them from MOSFETs. Therefore, MOSFETs are mainly used here. The following is a reunion. Corresponding to the on-resistance of the bipolar transistor is VCE(sat), which is the collector-emitter saturation voltage. This is the voltage drop when the transistor is turned on when a predetermined collector current flows. Therefore, the resistance at turn-on can be obtained from this value.
A MOSFET (an example of Nch in the figure) is turned on by creating a channel between the source and the drain by applying a voltage to the gate. In addition, the gate electrode is insulated from the oxide film by the source and the drain, so that the current in the sense of "on" does not flow. However, a charge called "Qg" is needed.
About MOSFET, will introduce again in detail.
The IGBT is a composite structure of a bipolar transistor and a MOSFET. It is a transistor developed to take advantage of the advantages of MOSFETs and bipolar transistors.
Similarly to the MOSFETs, high-speed operation can be performed through the gate voltage control, and the high breakdown voltage and low on-resistance of the bipolar transistors are also provided.
Working in the same way as MOSFETs, current flows by applying voltage to the gate to form a channel. The structure MOSFET (for Nch, for example) is the same N-type source and drain current, and the IGBT flows from the P-type collector to the N-type emitter, ie, the same as the bipolar transistor. . Therefore, there is a gate-related parameter of the MOSFET, and a collector-emitter related parameter of the bipolar transistor.
Comparison of basic operating characteristics
The operating characteristics of these three transistors are different. The following are the characteristics of Vce/Vds with respect to the basic Ic/Id. Power components are basically used as switches, so they are generally used as low as possible with Vce/Vds. This is one of the representative characteristics of which transistor is most suitable when it comes to the circuit conditions used.
1200 Puffs Disposable ecig have a completely enclosed design, reducing the need for charging and replacing cartridges. The no-charge design also reduces the occurrence of faults. It is understood that with rechargeable e-cigarettes, each cartridge needs to be charged at least once and the battery efficiency is extremely low, while the design of disposable ecig can solve this problem very well.
1200 Puff E-Cigarette,1200 Puff E-Cigarette For Sale,Best 1500 Puff E-Cigarette,Best 1200 Puff E-Cigarette For Sale
Shenzhen E-wisdom Network Technology Co., Ltd. , https://www.healthy-cigarettes.com