Powerful storms and bursts of lightning are part of most people’s summers. Local lightning strikes, though a rarity in terms of occurrence, do happen, and the damage they can cause to electronics by way of power surges can be headache-inducing.
Now, for the average electronics user, there’s not much one can do outside of unplugging devices and appliances during a storm, or otherwise purchasing a warranty on them. For the engineer and designer tasked with creating these devices, though, some steps can be taken to protect electronics from random bursts of power.
Lightning strikes and other forms of unpredictable electric shock like electrostatic discharge are referred to as a transient voltage. When a transient occurs, it results in an electromagnetic disturbance on electrical and communication lines connected to the electronic equipment. Technology is available to protect against these random bursts of electricity, and they are fast to respond as well as able to dissipate the energy without damaging the device.
The most common of these particular components include metal oxide varistors (MOVs), TVS diodes, and gas discharge tubes (GDTs). This is for your typical electronic devices. When it comes to telecom / datacom applications, TVS diode arrays, and protection thyristors are the best-suited components.
In terms of smaller devices, an important thing to understand is that as the components get smaller, the sensitivity to electrical stresses increases. Microprocessors are a good example. The structures and conductive paths in place in most of these devices are unable to handle the high currents that result from transients like electrostatic discharge or ESD. They operate at low voltages, so when a voltage disturbance occurs, it must be controlled in such a way so as to prevent not only device interruption, but also latent or catastrophic failures. Circuit protection on these devices typically feature low clamping voltage, low capacitance, and low leakage current.
Littelfuse, which specializes in circuit protection technologies, offers one of the broadest portfolios of this line of technology. Here are some examples of the products the company has to offer, and how they protect electronics from random transients:
TVS diodes are used to protect semiconductor components from high-voltage transients.
TVS diode arrays (SPA® Diodes) are designed to protect analog and digital signal lines (e.g., HDMI, USB, Ethernet, Audio, etc.) from electrostatic discharge.
PulseGuard ESD suppressors protect high-speed digital I/O lines (e.g., HDMI, USB, , etc.) without causing signal distortion.
Varistors suppress transient voltages like lightning and other high level transients found in industrial, AC line application, or lower-level transients found in automotive DC line applications.
SIDACtor devices suppress overvoltage transients in telecom and datacom equipment (e.g., xDSL, POTS, etc.) vis-à-vis divert currents to the ground within nanoseconds of reaching their breakover voltage.
Gas discharge tube s offer fast response time to transient overvoltage events to reduce risk of equipment damage.
Switching thyristors are solid-state switches that are normally open circuits (very high impedance), capable of withstanding rated blocking / off-state voltage until triggered to on state.
PLED light-emitting diode protectors provide a switching function that will bypass LEDs that go open circuit, and allow current to flow to the remaining LEDs in the string.
When selecting the right transient protection components for your design, there are several important parameters to be considered, including reverse standoff voltage (VR), peak pulse current (IPP) and maximum clamping voltage (VC max). To help you choose the right component for your particular product, check out Littelfuse’s circuit protection technology matrix below:
To learn more about how to integrate top-of-the-line circuit protection measures against random transients, download the Product Selection Guide below.
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