A power supply overvoltage protection circuit based on a high-voltage retaining wall

Abstract

The invention relates to the technical field of high-voltage overvoltage protection of DC power supply for industrial field instruments, in particular to a power supply overvoltage protection circuitbased on a high-voltage retaining wall. The circuit includes successively connected surge protection and absorption module, overcurrent and anti-reverse connection protection module and high voltage protection module, the surge protection and absorption module is used for transient overvoltage protection and filtering out common-mode and differential-mode interference signals in the line, the overcurrent and anti-reverse connection protection module is used for preventing power supply reverse connection damage and overcurrent protection, and the high voltage protection module is used for clamping the spike voltage so that the back-end circuit voltage is clamped. The high-voltage protection module of the invention makes the voltage stabilizing tube reverse breakdown when the high-voltage signal is available, so that the voltage behind the high-voltage retaining wall circuit is clamped within a reliable voltage range, thereby improving the working stability of the whole circuit, eliminating the need for frequent stopping at the site, and greatly improving the reliability and the practicability of the industrial instrument DC power supply at the site.

Description

technical field The invention relates to the technical field of high-voltage overvoltage protection of DC power supplies for instruments used on industrial sites, in particular to a power supply overvoltage protection circuit based on a high-voltage retaining wall. Background technique Start and stop of a wide variety of processing machinery and power equipment in industrial sites, such as electric welding, frequency conversion equipment, etc. These interferences can not only act on the systems and instruments on site in the form of electromagnetic fields, but also cause interference by invading the system through the power supply. The interference caused by the power supply is the most direct and even destructive. Therefore, in order to improve the reliability of industrial control field equipment and instruments, the reliability of the power supply must be ensured first. Although there are few faults of DC power output overvoltage, overvoltage is destructive, and the mo...

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Problems solved by technology

However, varistors are greatly affected by temperature and have high residual voltage. For example, the residual voltage of a varistor with a nominal 46V may reach 65V, and the peak value of the residual voltage is even higher, reaching more than 100V, far exceeding the voltage during normal use. range, resulting in damage to components; and TVS devices absorb less power, relatively high unit price and other reasons, there are restrictions on the use of places

Using the above DC power supply overvoltage protection methods, there will still be various risks such as hardware damage, software errors, electromagnetic interference, and even personal injury on site.

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