Input voltage overvoltage protection circuit

Abstract

The invention discloses an input voltage overvoltage protection circuit which comprises a zero crossing detection module, an overvoltage detection module, a protection control module and a switcher. The zero crossing detection module is used for detecting whether the input voltage provided by an alternating current power source is in a zero crossing time frame or not. The overvoltage detection module is used for detecting whether overvoltage occurs in the input voltage provided by the alternating current power source or not. The protection control module is used for controlling the switcher to be disconnected when overvoltage occurs in the input voltage and controlling the switcher to return to the breakover state when overvoltage does not occur in the input voltage and the input voltage is in the zero crossing time frame. According to the protection circuit, when overvoltage occurs in the input voltage, the switcher is controlled to be disconnected, and the switcher is controlled to be in the breakover state again when overvoltage does not occur in the input voltage and the input voltage is in the zero crossing time frame; due to the fact that when the switcher is in the breakover state again, and the input voltage is in the zero crossing time frame, the situation that when the switcher resets again, the circuit is damaged due to excessively high input voltage is avoided, and the overvoltage protection of the input voltage can be achieved safely and effectively accordingly.

Description

technical field [0001] The invention and the field of overvoltage protection, in particular, relate to an input voltage overvoltage protection circuit. Background technique [0002] When the power supply works in a high-voltage input environment, the electrolytic capacitors and main power switch tubes in the power supply are prone to insufficient stress, which will cause serious heating. If the circuit does not have an overvoltage protection function, it is easy to cause a fire. The conventional overvoltage protection circuit consists of It is composed of overvoltage detection module, protection control module and relay. The overvoltage detection module is used to detect the input voltage. When the input voltage reaches the overvoltage detection reference value, the protection control module sends a signal to turn off the relay, but it needs to be reset after disconnecting the relay. At this time, the input AC voltage may be just at the peak value. At this time, a high surge...

AI Technical Summary

Problems solved by technology

[0002] When the power supply works in a high-voltage input environment, the electrolytic capacitors and main power switch tubes in the power supply are prone to insufficient stress, which will cause serious heating. If the circuit does not have an overvoltage protection function, it is easy to cause a fire. The conventional overvoltage protection circuit consists of It is composed of overvoltage detection module, protection control module and relay. The overvoltage detection module is used to detect the input voltage. When the input voltage reaches the overvoltage detection reference value, the protection control module sends a signal to turn off the relay, but it needs to be reset after disconnecting the relay. At this time, the input AC voltage may be just at the peak value. At this time, a high surge current will be generated in the input circuit, and the circuit safety is difficult to be guaranteed.

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