什么是寄生晶体管

寄生晶体管就是指有寄生电容的晶体管。它属于半导体集成电路的一种，其中用得最普遍的是TTL与非门。它们会将若干个晶体管和电阻元件组成的电路系统集中制造在一块很小的硅片上，封装成一个独立的元件。寄生晶体管也是半导体三极管中应用最广泛的器件之一。

扩展资料

寄生损耗：

由于高频条件下，变换器中的各元器件都存在一定的寄生参数，这些参数相互作用，将引起一系列复杂的电路工作模态变化过程，使电路的运行速度变慢，改变频率的响应，这时产生的能量损耗被称为寄生损耗。

介绍：

能量由一种形式转换为另一种形式时，不可避免的会伴有能量的损失。衡量能量利用有效率的指标称之为能效。在提倡节能减排的现代社会，为了保证较高的生活品质，必须寻求能效提高之道。电能的应用在人类日常生活和工业生产等各个方面都不可或缺。

通过减少用电时间来减少电能消耗是一种行之有效的方案；电力电子学更关注的是如何减少功率损耗，即如何提升电子设备的内部效率或改进工艺流程，来达到提高能效的最终目的。

寄生的含义是指原本没有在电路的某个地方设计电阻、电容或电感，但由于一些电路元件本身的制造工艺和结构特性而形成的寄生电阻，以及布线结构之间存在的互容或互感，就好像是寄生在元件内部或者布线之间，所以叫寄生电阻、寄生电容或寄生电感。

随着频率的不断增高，电路中原来可以忽略的一些寄生参量开始作用。在高频变换器中广泛存在着一些寄生参数，由寄生参数造成的寄生损耗也越来越不容忽视。

寄生损耗使得电路很难达到理想的性能，阻碍电路的发展，因而减小寄生损失变得十分重要。

高频变换器中主要的寄生损耗及来源分析：

1、开关器件的寄生参数

目前广为采用的开关器件多为半导体器件，其寄生参数主要取决于器件本身的设计构造。二极管的寄生参数包括：等效寄生电阻，内部引线导致造成的寄生电感，在 PN结附近形成的等效寄生电容。

典型的高频大功率开关器件 IGBT，是由MOSFET 和晶体管技术结合而成的复合型器件，结合了前者开关速度快、工作频率高、热稳定性好以及后者耐压高、耐流大等优点，在电机控制、高频开关电源，以及低速、低损耗的领域备受亲睐。

其寄生参数主要为

①源极、门极和漏极的极间电容；

②漏极电感、门极驱动等效电感以及源极电感；

③管脚引线电感；

④IGBT 在漏极与源极之间的寄生PNP 晶闸管。

2、高频变压器的寄生参数

高频变压器是隔离式电力电子变换器的核心环节之一，其寄生参数主要有高频变压器漏感和寄生电容，其中，漏感包括一次侧和二次侧的绕组间漏感；寄生电容则分为匝内和层间寄生电容。

3、电感、电容、电阻的寄生参数实际上，在高频情况下，电感、电容和电阻都等效于一个电容、一个电感和一个电阻的串连，各自都存在着等效的寄生电感或寄生电容或寄生电阻。电阻和电感的寄生参数均与其自身的材料有关，电容则主要受谐振频率的影响。

4、控制电路的PCB 板电力电子变换器印刷板上的印制导线之间相互耦合而形成了电感和电容等寄生参数，实际应用中，可重点考虑电路中具有高电流变化率的回路和高电压变化率节点之间的连接线。

5、开关管与散热器间的寄生电容在开关管功率较大时，开关管一般都需要加上散热器，散热器与开关管之间存在寄生电容。

6、导线的寄生参数

随着频率的升高，导线将逐渐由电阻特性变换为电感特性。一般工作在音频范围以上的导线均表现出电感特性，导线可等效为一个可以辐射 RF 能量的天线。

参考资料来自：百度百科-寄生损耗

In addition to improvements in chip performance, the shell packaging technology is also a great breakthrough, IR inversion in the development of field-effect transistor, also known as "FlipFET" on the basis of this year introduced the DirectFET, as shown in Figure 6. Its source and gate inversion result can be directly welded in the printed circuit board, the drain at the top of the weld metal in its shell, if necessary, by the radiator or direct contact with the equipment enclosure. DirectFET size equivalent to the traditional SO-8 plastic (plastic with an area of about 4x5 mm2) shell. In such a small device, the first structure of a double-sided cooling. It is a lead frame, no-lead solder joints of the device, it brought about a series of advantages: it's non-resistor chip package (DFPR) is only 0. 1mW, device thickness of only 0. 7mm, resistance and parasitic inductance have dropped significantly. Such characteristics make it especially suitable for the above-mentioned computer of the latest generation of CPU. In the multi-phase circuits, each with only two of 30 security DirectFET can transfer current. Increase its current rate of 400 per delicate security, the working frequency of 1-2 MHz.

Secondly, you must be focused on power semiconductor devices in the IC direction: as a result of the development of MOSFET and IGBT, and their matching to provide a trigger signal power integrated circuit PIC (Power IC) have also developed rapidly. At that time, also known as MOS gate drive MGD (MOS Gate Driver) or control integrated circuit CIC (Control IC). With the expansion of the scope of application: such as motor drives, lighting, various power supply and so on, CIC of the cultivars have been rapidly increasing. These CIC in the development process

And gradually from a simple function to trigger the special needs of a wide range of applications development. PIC is the earliest that can be used in high voltage IC, therefore, also known as high-voltage IC (HVIC). However, many applications such as communications, computers, portable power supply and so on, they do not require high voltage, but demand for the special needs of the development of application specific integrated circuit. Because of their combination and application of power semiconductor devices, we have the power to include them in a class of semiconductor devices. So now the power semiconductor devices in the family, there are many integrated circuits. Many of these power devices with integrated circuits inside, some outside while the separation of power devices. Judging from this point, the limits of power and microelectronics has become increasingly blurred. If a large number of computer applications in power modulation device voltage LDO (Low Drop Out) is one example. It does not belong to switch applications.

As a result of a large number of integrated circuits into the power semiconductor devices, which consider the power semiconductor integrated circuits and devices to do the same in the chip or device on the development of the natural line of thought. Done in the same chip, the original is the concept of power integrated circuits, but their power often relatively small. Done in the same package, easy to increase power capacity, a number of passive components is also possible to join, here often called multi-chip module (MCM).

IR last year iPOWIR developed is a typical multi-chip module. It will power devices to control the use of integrated circuits, or in combination with pulse-width modulation (PWM) integrated circuit, according to the needs of power supply design, using BGA packaging technology portfolio in the same device (as shown in Figure 7) . Multi-chip device that greatly simplifies the power supply design staff. Components reduces the number and percentage of the area, there has been a lot of performance improvement. iPOWIR development is considered DC-DC conversion of the future. But, in fact, a wide range of applications in other fields, as long as the requirements of further integration, MCM structure and will there will be more and more. Therefore, it is the power semiconductor devices important direction of development.

In the above presentation, the development of MOSFET has been referred to as 4C industry provides an important foundation. 4C industries which, at present it is the most active direction of the product. We can understand: in the communications, computer, consumer electronics and automotive development, will require many, many close contacts and IC of all types of power semiconductor devices. Each of these aspects can be used to introduce a lot of space. Not detailed here.

Add: Conclusion

To sum up, the power semiconductor devices the past few years, constantly changed a lot. So can no longer look at a fixed vision of the development of power semiconductor devices. For example, not simply thyristor power semiconductor devices and an equal sign painting, or drawing an equal sign and discrete devices. Must not power semiconductor devices and microelectronics artificially separated, it seems only semiconductor microelectronics. These will impede the development of power semiconductor devices, in the long run will hinder the development of microelectronic devices. Development strategy in order to avoid the power semiconductor devices as a simple process only to be completed on the low-tech products. And the preferential policies available only to integrated circuit industry. China has not been very good to the development of modern power semiconductor devices, the lack of modern power semiconductor devices is a comprehensive understanding of the factors I am afraid. Information technology to stimulate industrialization in the wave, it is imperative that different semiconductor devices have a balanced development.

Conclusion

To sum up, the power semiconductor devices the past few years, constantly changed a lot. So can no longer look at a fixed vision of the development of power semiconductor devices. For example, not simply thyristor power semiconductor devices and an equal sign painting, or drawing an equal sign and discrete devices. Must not power semiconductor devices and microelectronics artificially separated, it seems only semiconductor microelectronics. These will impede the development of power semiconductor devices, in the long run will hinder the development of microelectronic devices. Development strategy in order to avoid the power semiconductor devices as a simple process only to be completed on the low-tech products. And the preferential policies available only to integrated circuit industry. China has not been very good to the development of modern power semiconductor devices, the lack of modern power semiconductor devices is a comprehensive understanding of the factors I am afraid. Information technology to stimulate industrialization in the wave, it is imperative that different semiconductor devices have a balanced development.

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