A dual-purpose switch circuit for preventing reverse connection and suppressing boot inrush current

Abstract

The invention discloses a dual-purpose switching circuit for preventing reverse connection and suppressing boot surge current, which comprises a delay circuit, a driving circuit, a switching device and a reverse-connection-proof and surge-suppressing circuit. The output end of the delay circuit is connected with the input end of the driving circuit, the output end of the driving circuit is connected with the switching device, and the anti-reverse connection and surge suppression circuit are connected in parallel with the switching device. The inrush current suppression circuit and the anti-reverse connection circuit are combined together. Compared with the prior art scheme in which the electromagnetic relay is used as the switching element, the circuit is small in size, and and the drive circuit is simple and reliable; Compared with the scheme of controlling the conduction state of the MOS transistor to suppress the inrush current, the circuit is more suitable for medium and high poweroccasions due to the limited dissipation power of the MOS transistor, and does not need to accurately control the conduction state of the MOS transistor. The invention has the characteristics of small volume and simple and reliable driving circuit.

Description

technical field [0001] The invention relates to the field of electronic circuits, in particular to a dual-purpose switch circuit for preventing reverse connection and suppressing startup surge current. Background technique [0002] The surge suppression circuit with input anti-reverse connection function in the prior art adopts the following circuit structure: the input anti-reverse connection and its startup surge current suppression circuit supplies power to it through the DC / DC auxiliary power supply, and the RC delay circuit relay absorbs the power. Closing delay time. Before the relay is closed, the diode and current limiting resistor are used to prevent reverse connection and surge current. After the relay is closed, the main current flows through the relay. The circuit is realized by relays, Zener diodes, LM431, PNP transistors, diodes, resistors, capacitors, etc. However, the defect of the above switch circuit is that it needs a separate auxiliary power supply, and ...

AI Technical Summary

Problems solved by technology

For DC input power supply, the input capacitor is generally an electrolytic capacitor with polarity. When the power supply is reversed by mistake, it will cause irreversible damage to the secondary power supply.

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