An overvoltage limiting circuit

Abstract

The invention provides an overvoltage limiting circuit. According to the circuit, an electrical equipment power supply with the need of protection of is connected with diodes from D1 to D5, capacitors from C1 to C3, an electrolytic capacitor CD1, resistors from R1 to R9, a potentiometer RW, an operational amplifier IC1, and a field effect transistor or an electronic switching devices O1 such as an IGBT and a triode. The overvoltage limiting circuit in working can quickly suppress and absorb transient voltage and consume energy so as to protect the electrical equipment, specifically, the transient voltage can be rapidly and reliably suppressed, especially a high power transient voltage surge, and only little electrical energy is consumed under a set suppression voltage value. The overvoltage limiting circuit also has a good suppression effect on repetitive high voltage pulses and transient voltage with long duration.

Description

technical field [0001] The invention relates to a protection circuit, in particular to an overvoltage limiting circuit. Background technique [0002] In the existing power supply grid, there are often various high-voltage pulses due to various reasons such as lightning and the access of other electrical equipment. In addition, high-voltage pulses sometimes appear in circuits powered by inverter power supplies. [0003] The interference of various high-voltage pulses will cause the electrical equipment to fail to work normally, and sometimes it will even damage the electrical equipment. In order to protect the safe and normal operation of electrical equipment, protective circuits such as gas discharge tubes, piezoresistors, transient voltage suppression diodes, or resistor-capacitor series absorbers are often used in circuits in the prior art to suppress this interference. However, the suppression power of gas discharge tubes, varistors, and transient voltage suppression di...

AI Technical Summary

Problems solved by technology

However, the suppression power of gas discharge tubes, varistors, and transient voltage suppression diodes is small, and repeated interference is easy to damage gas discharge tubes, varistors, and transient voltage suppression diodes.

In addition, gas discharge tubes, varistors, and transient voltage suppression diodes have a fatal flaw, that is, they have negative resistance characteristics, and the resistance often becomes smaller instantaneously under the impact of pulse high voltage, and they cannot immediately restore high resistance at the voltage limiting point, becoming The low resistance load of the power supply circuit is burned out by high current

However, the resistance-capacitance series absorption circuit has the problem of consuming the normal power supply energy of the circuit. If it absorbs a large power transient voltage impact, this energy consumption will become very large.

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