Designing For Circuit Protection

Many types of luminaires require circuit protection to protect against lightning zaps, short circuits, ESD, and other transients.  Lots of designers forget to account for these phemonena until after their luminaire is almost done.

In an effort to assist lighting OEMs, tinkerers, and other that design these products, Tyco Electronics Circuit Protection Division has recently released a design guide called High Brightness LED Lighting Solution Application Guide.  This covers DC/DC, AC/DC, battery powered and other means of powering HBLEDs.

Avnet stocks all of these products and can found at www.avnetexpress.com.

Take a look at Tyco Electronics CPD 2010 Catalog that was currently launched.  This new catalag outlines all of the circuit protection devices supported by TE.  These include PolySwitch resettable devices, PolyZen devices, 2Pro devices, polymer ESD (PESD) and silicon ESD (SESD) protection devices, chip fuses and gas discharge tubes.

Several new features have been included such as circuit diagrams, tetsing data, and safety standards that TE helps to comply to.  I have found previous editions to be helpful.  No doubt the 2010 catalog will as well.

As we have shown, just about all electronic designs need protection against overcurrent, overvoltage, and ESD events.  How can you learn about what events you have to protect against?  Tyco Electronics Circuit Protection Division has developed and online course called Circuit Protection University.  After registering for the site, you can take courses that cover the following:

• Circuit Protection Products Overview
• Coordinated Protection Overview
• Overcurrent Technology Overview
• Overvoltage Technology Overview
• Port Protection Overview
• New Silicon ESD Devices
• Selecting & Specifying PolySwitch™ Devices
• SuperSpeed USB - Circuit Protection Solutions

I found the Port Protection Overview course to be most helpful as it covers how to protect HDMI, USB, Ethernet, and other common port technologies found on numerous designs.  If you have taken any of these courses, please leave a comment and let us know what you think.

In many applications, system designers and engineers have to worry about long lasting high voltage/high current transients that their systems might see.  You may think, hey that’s and ESD shock.  You’d be right, but ESD shocks only last a few microseconds.  We are talking about events that last hundreds of milliseconds. 

An example of this might be a load dump in an automotive battery application.  These occur when a discharged car battery is removed from VBAT while the alternator takes over powering the rest of the vehicle electronics at start up.  These surges may be as high at 85V.  One way to combat this is to use overvoltage protection devices like Tyco Electronics Raychem MOVs to dissipate the energy of the surge.  TE Raychem has developed a good guide on how to choose the right part for your specific application.

Tyco Electronics Circuit Protection Division (CPD) has just announced a new blog on emerging circuit protection schemes and products.  If you notice, all of the authors and bloggers work directly for Tyco Electronics CPD and have multiple years interfacing with customers and supporting new applications.

The blog list topics of interest in various areas: Automotive, Comms, Industrial, Multimedia, and Portable Electronics.  I have found the information to be informative and useful for what I have been working on.

They have also listed information on Lighting, USB 3.0, and other areas of interest.

More information on the blog can be found here.

Have you ever had repeated failures to your PCB but couldn't figure oput what caused it?  You very well may have a failure due to inappropriate circuit protection.   This could be an overcurrent, overvoltage, or ESD attack on your system.  In an effort to help attack these issues, Tyco Electronics has set up their Circuit Protection University

This short training program will give a brief overview of various types of failures your system may encounter.  It will also show which types of devices TE has to help solve these problems.

If you have questions about these devices, please e-mail Avnet's Centralized Support Team at centralized-support@avnet.com and they can help answer any issues you may have.