跳转至主要内容

Bill Russell

Recent Posts

多少保护才足够?

Posted by Bill Russell on 14 January 2021

When designing an electronic system, the often overlooked and underestimated subject of protection must be considered. In some cases, the designer may be working to meet a certain standard such as IEC 61000-4-2 for electrostatic discharge (ESD) immunity. Equipment which is installed in harsh operating environments, such as remote meters, robotics and telecommunications systems, will require higher levels of lightning protection. These are somewhat obvious requirements. Other protection concerns include short circuits, voltage spikes, dirty power, cable discharge events, and so on. With all these transient threats, a designer may become overwhelmed and ask: how much protection is enough to ensure a reliable system?

Read More

Tags: Circuit Protection

TVS 峰值脉冲功率:是不是越高越好?

Posted by Bill Russell on 15 April 2020

One of the most misunderstood ratings for transient voltage suppressor (TVS) diodes is peak pulse power (PPP). Many engineers will select surge protection components based primarily on rated peak pulse power and assume that their system will be well protected. After all, it seems logical to assume that a higher power rating means the device can absorb higher transient currents and therefore should be superior. While peak pulse power ratings may be considered in the selection process, the device should not be chosen solely on this parameter. To illustrate why, let us review the definition of TVS peak pulse power.

Read More

Tags: Circuit Protection

TVS?只是个普通二极管,对不对?第二部分

Posted by Bill Russell on 18 March 2020

降低钳位电压

在第一部分中,我们了解到瞬态电压抑制二极管 (TVS) 的钳位电压是关键的保护参数。TVS 制造商一直在努力降低钳位电压,以适配不断缩小的 IC 尺寸和对过电压事件的更高敏感性。实现低钳位电压的一种方法是将器件设计为一旦触发即可“折回”至较低电压的结构。折回可深可浅,具体取决于预期的应用。实现深折回的一种方法是设计一种自触发晶闸管 TVS 结构(图 4)。

Read More

Tags: Circuit Protection

TVS只是个普通二极管吗?第一部分

Posted by Bill Russell on 12 March 2020

我记不清有多少人这么评价硅基瞬态电压抑制器 (TVS) 了。TVS 制造商可能也在随大流。我们通常将这些器件称为 TVS 二极管或静电放电 (ESD) 保护二极管。从技术上来说,二极管是一种两端子器件,主要沿一个方向传导电流。TVS 或 TVS 二极管也是两端子器件,用于在反向击穿区域中传导电流。如果把它看作“普通二极管”的话,我们是不是可以随便选择 TVS 二极管或相关类型的二极管来保护电路呢?真这样做的话,结果可能令人失望。

Read More

Tags: Circuit Protection

以太网保护方法

Posted by Bill Russell on 19 February 2020

以太网端口会遭受外部瞬态事件,如静电放电 (ESD)、电气快速瞬变 (EFT)、闪电和电缆放电事件 (CDE)。外部瞬态电压抑制 (TVS) 二极管通常用于保护以太网 PHY 芯片免受这些威胁。但关于如何连接 TVS 二极管才能实现最大成效,人们仍有很多困惑。通常的建议是在 RJ-45 连接器附近用二极管连接每根信号线和接地线。实际上,TVS 应跨信号对连接,并位于连接器的 PHY 侧。在此博客中,我们将探讨其中的原因。

Read More

Tags: Circuit Protection

Transient Protection of RS-485 Buses in Industrial Applications

Posted by Bill Russell on 04 February 2020

Modern industrial networks rely on robust RS-485 communication links for long distance data transmission. These networks operate in harsh electromagnetic environments and must be capable of withstanding electrical overstress (EOS) events without damage. Semtech’s Protection Products Group application engineering team recently had the opportunity to work with Renesas Corporation engineers on a reference design for protecting Renesas’ fault-protected RS-485 transceivers, used in industrial applications.

Read More

Tags: Circuit Protection

订阅博客

Recent Posts