Power Supply Over-Voltage Protectors

Over-voltage protection, also known as an OVP, is a circuit that prevents excessive voltage damage to downstream circuitry. There are several types of power supply over-voltage protectors to choose from, including high-voltage protection circuits, as well as clamping and switch devices.

We stock products from reputable brands like Bel Power Solutions, Siemens, and SolaHD. Plus, you can refine your search using our filter tools so you can identify the exact OVP device you need.

Search through our online selection of overload and over-voltage protection products and start your order today. Find out more information about any of our products by getting in touch with our team of friendly trade experts today.

How do power supply over-voltage protectors work?

Power supply over-voltage protectors work by monitoring the DC voltage from an external power source. They're also known as DC over-voltage protection or mains over-voltage protection.

Over-voltage can occur for several reasons. It could be due to a fault or disconnection. But because these aren't large in magnitude, good-quality insulation is usually sufficient to prevent damage.

However, if something more intense such as lightning strikes become a threat, over-voltage protection devices can help to reduce the damage caused. This is why power supply over-voltage protection is key in complex electrical circuits.

What are the different types of power supply over-voltage protectors?

There are various types of power supply over-voltage protectors.

Crowbar circuits

A short circuit or low resistance path is placed across the output of the power supply when an over-voltage or surge condition arises. This is likened to dropping a crowbar across the power supply's terminals. Doing this shorts the output line to ground and limits the current on the circuit.

Crowbar circuits are generally used in benchtop power supplies that provide DC voltage.

These high-voltage protection circuits typically consist of the following:

• Silicon controlled rectifier (SCR)
• Zener diode
• Resistor
• Capacitor

Crowbar clamping

Crowbar clamping OVP methods differs slightly. While a crowbar circuit pulls the voltage below the trigger level, often near ground voltage, a clamp stops the voltage from surpassing a preset level.

This is done by placing a Zener diode across the output of the regulated power supply. The Zener diode voltage should be slightly above the maximum rail voltage. If the voltage rises too high, it will begin to conduct while clamping the voltage at a value that's higher than the rail voltage.

After this overload voltage protection method has been actioned, power must be removed to allow the crowbar to get back to its neutral condition.

Series-connected switch

This connects the supply line with a MOSFET or transistor connected to a switch in a series. If over-voltage occurs, the OVP circuit shuts off the MOSFET and disconnects the downstream circuit to avoid any damage from occurring.

What are the benefits of power supply over-voltage protectors?

Power supply over-voltage protection devices are key safety features. By shutting down the supply or clamping the output, they can help prevent electronic circuits and components from being damaged when the voltage rises above the preset level. They're an important part of hazard prevention in electrical systems and devices. Over-voltage for more than just a nanosecond can cause a significant amount of damage.

When you choose the right OVP, it shouldn't interfere with the normal function of the circuit. Plus, it will be fast enough to respond as soon as over-voltage occurs to protect the downstream circuit.

Why choose RS for your power supply over-voltage protectors?

You can find several high-quality overload and over-voltage protection products in our online selection. We're one of North America's leading distributors of power products and accessories, which means we take pride in offering customers a superb range of OVP devices from leading brands. Our products are reliable and suited to a number of trade applications across industries. Meanwhile, our ECIA, CTPAT, and NAED accreditations will help give you added peace of mind.

Take a look at our collection of power supply over-voltage protection products today and secure your quick, no-hassle delivery. Want to find out more about our offering? You can get in touch with our team of experts to tap into their pool of knowledge. Otherwise, our user guides and industry updates can be found on the expert hub.