An overvoltage protection circuit and power supply equipment

Abstract

The application discloses an overvoltage protection circuit and power supply equipment, wherein the overvoltage protection circuit is composed of a MOS transistor, a bias module and a control module, and when the voltage at both ends of the load does not exceed the overvoltage protection point, the control The module controls the MOS tube to be in a fully conducting state. At this time, the voltage at both ends of the load is equal to the input power supply voltage; when the voltage at both ends of the load exceeds the overvoltage protection point, the control module controls the MOS tube to enter a linear conduction state , the voltage at both ends of the MOS tube increases, thereby reducing the voltage at both ends of the load, so that the voltage at both ends of the load is lower than the input power supply voltage, so as to avoid the load being affected by surge voltage or overvoltage, and the MOS tube is in the presence of surge voltage or overvoltage , always keep the voltage at both ends of the load at the overvoltage protection point, and achieve the purpose of stabilizing the voltage provided to the load at the overvoltage protection point when a surge voltage or overvoltage occurs.

Description

Technical field [0001] This application relates to the field of circuit design, and more particularly to an overvoltage protection circuit and a power supply device. Background technique [0002] As the degree of precision of electronic devices continues to increase, the requirements for the supply voltage stability of the power supply loop are increasingly high. [0003] However, the power supply circuit may introduce some surge voltages due to the interaction between the equipment or other causes, or cause an uncontrollable overvoltage of the power supply loop. In order to ensure the normal operation of the power supply circuit, the lightning protection system or overvoltage needs to be introduced. Protect the equipment to suppress the surge voltage or overvoltage. [0004] However, in the actual application process, the action threshold of lightning protection system and overvoltage protection device is fixed, and when the surge voltage exceeds the action threshold, the power ...

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Problems solved by technology

[0003] However, the power supply circuit may introduce some surge voltage or uncontrollable overvoltage in the power supply circuit due to the mutual influence between devices or other reasons. In order to ensure the normal operation of the downstream equipment of the power supply circuit, a lightning protection system or overvoltage Protect equipment to suppress surge voltage or overvoltage

[0004] However, in the actual application process, it is found that the operating thresholds of the lightning protection system and overvoltage protection equipment are fixed, and when the surge voltage exceeds the operating threshold, the power supply will be cut off, so that the load cannot obtain continuous and stable power. supply, it is difficult to meet the power requirements of some refined equipment

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