瞬态电压抑制装置的介绍

　　简介

　　瞬态电压抑制（TVS）保护装置

　　如屏蔽电缆、撬棍、过滤器和夹紧

　　集成电路制造的新进展技术提供TVS二极管与几个技术和成本优势相比，传统的EMI器件。设备已被广泛使用了若干年来解决EMI问题。这个将传统电视设备的属性进行比较功能相对较新的选项，雪崩二极管电视EMI滤波器。这些TVS器件可以用来实现高EMI高免疫水平无显著增加了电路的成本和复杂性。

　　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.