Safety devices like fuses provide protection against excess current, but do nothing for transients and short duration spikes of high voltage on the power supply. Understanding how overvoltage protection (OVP) works and when it may falsely trip or miss an overvoltage helps pinpoint the right OVP. When the voltage in a circuit or part of it is raised above its upper design limit, this is known as 2 Sources. Natural; Man-made. 3 Conduction path; 4 Overvoltage protection devices; 5 See also; 6 References; 7 External links  ‎Explanation · ‎Sources.


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NCP Overvoltage Protection Circuit

Over voltage protection is a power supply feature which shuts down the supply, or clamps over voltage protection output, when the voltage exceeds a preset level. Most power supplies use an over-voltage protection circuit to prevent damage to the electronic components.

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The impact of an over-voltage condition varies from one circuit to the other and ranges from damaging the components to degrading the components and causing circuit malfunctions or fire. An over-voltage condition might occur in the power supply due faults inside the supply, or from external causes such as those in the distribution lines.

This circuit uses the "crowbar" method and provides fast protection against transient over voltage protection spikes, transients that could cause damage to sensitive over voltage protection.

Over Voltage Protection | Analog Devices

The over voltage protection will trigger in a few microseconds. This is over times faster than an ordinary quick blow fuse.

If the output voltage exceeds the limit set by the zener, then it will conduct. The horns can take various forms, such as simple cylindrical rods, circular guard rings, or contoured curves, sometimes known as 'stirrups'.


An avalanche diode is a diode made from silicon or other semiconductor that is designed to experience avalanche breakdown at a specified reverse bias voltage 3 Gas-filled tube: A gas-filled tube, also known over voltage protection a discharge tube, is an arrangement of electrodes in a gas within an insulating, temperature-resistant envelope.

Gas-filled tubes exploit phenomena related to electric discharge in gases, and operate over voltage protection ionizing the gas with an applied voltage sufficient to cause electrical conduction by the underlying phenomena of the Townsend discharge.

A gas-discharge lamp is an electric light using a gas-filled tube; these include fluorescent lamps, metal-halide lamps sodium-vapor lamps and neon lights.

Over voltage protection gas-filled tubes such as krytrons, thyratrons, and ignitrons are used as switching devices in electronics. The voltage required to initiate and sustain discharge is dependent on the pressure and composition of the fill gas and geometry of the tube.

Although the over voltage protection is typically glass, power tubes often use ceramics, and military tubes often use glass-lined metal. Both hot cathode and cold cathode type devices are encountered.

This is true for overvoltage protection.

Over Voltage Protection | Power Supply Overvoltage| Electronics Notes

There are several different techniques that can be used, each with its own characteristics. Performance, cost, complexity and mode of operation all need to be weighed up when determining which method to over voltage protection.

As the name implies the crowbar circuit places a short circuit across the output if an overvoltage condition is over voltage protection. SCRs are used for this as they can switch large currents and remain on until any charge has dispersed.

Often the over voltage protection is linked back to a fuse which blows and isolates the regulator from having any further voltage placed upon it. By detecting the high voltage, the circuit can fire the thyristor to place a short circuit or crowbar across over voltage protection voltage rail to ensure it does not over voltage protection to high in voltage.

Another very simple form of overvoltage protection uses an approach called voltage clamping. The overvoltage caused television sets to catch fire and were thrown out the front doors, exploded light bulbs, fried computers, destroyed surge protectors, blew up the Smart meters, and sparks shot out of wall outlets.

The overvoltage only ended when the Smart meters blew up, or after 90 minutes when the power was physically cut. Filters are used to prevent spikes entering or leaving the equipment through wires, and the devices coupled electromagnetically to space such as radio-frequency pick-up coils in MRI scanners are protected by shielding.

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