瞬態(tài)電壓抑制裝置的介紹

　　簡介

　　瞬態(tài)電壓抑制（TVS）保護裝置

　　如屏蔽電纜、撬棍、過濾器和夾緊

　　集成電路制造的新進展技術(shù)提供TVS二極管與幾個技術(shù)和成本優(yōu)勢相比，傳統(tǒng)的EMI器件。設(shè)備已被廣泛使用了若干年來解決EMI問題。這個將傳統(tǒng)電視設(shè)備的屬性進行比較功能相對較新的選項，雪崩二極管電視EMI濾波器。這些TVS器件可以用來實現(xiàn)高EMI高免疫水平無顯著增加了電路的成本和復(fù)雜性。

　　Background

　　Transient surge voltages are a major cause of poor reliability. Surge voltages can also cause erratic behavior in control circuits and effect the normal operation of electronics. Transient surge voltages can usually be attributed to：

　　? Sudden load changes in adjacent circuits

　　? Power source fluctuations

　　? Coupled electronic disturbances via cables

　　? Opening or closing of switch contacts

　　? Lightning

　　? ESD

　　The power supply and data cables are common entry points for conducted and coupled transient surge voltages. In many systems， a common power supply is shared by a number of electronic modules. The modules are also connected to each other through communication buses that are often located in the same wire bundle as the power lines. The parasitic cable capacitances and inductances provide a path for the power line surge voltages to be coupled into the data lines.

　　TVS Protection Options

　　TVS devices can be categorized as a cable， crowbar， clamping or filter device. Figure 1 provides a schematic representation of the TVS devices. Each TVS option has unique advantages and disadvantages that are summarized in Table 1. Many systems use a combination of TVS devices to create a protection circuit that combines the advantages of the different TVS options.