DC over-voltage protection circuit

Abstract

The present invention provides a DC overvoltage protection circuit, including a voltage limiting circuit mounted on the circuit board of the case, characterized in that the voltage input end is electrically connected with a variable impedance electronic switch, an overvoltage detecting circuit and a ripple detecting circuit respectively, the overvoltage detecting circuit and the ripple detecting circuit are electrically connected to the input end of the variable impedance electronic switch, the output end of the variable impedance electronic switch is electrically connected to the spike snubber circuit, output voltage by the voltage output end. The invention is used as an attaching device which is serial connected on the front of the product using electricity, capable of preventing spike and surge, the circuit has lower voltage drop at the same time, the circuit is general, fir for product having larger power and smaller power, having widely application. The invention adopts unit having smaller volume adding the upper limit of the working voltage of the present product, greatly improving the power supplying compatible ability and the credibility of the electrical appliance compared with the traditional spike, surge preventing circuit.

Description

technical field [0001] The invention relates to an overvoltage protection circuit device of an airborne electronic product. Background technique [0002] General airborne electronic products have a limited range of input power requirements, and the power supply may exceed the upper limit, such as overvoltage surges. This requires the product to have a certain ability to withstand overvoltage. Most of the airborne electronic products in the prior art usually adopt the method of connecting resistors in series at the input end and adding a transient suppressor for overvoltage resistance, but the application range thereof is very limited. On the one hand, this circuit has a certain effect on the peak with a narrow pulse width, but it often causes the resistor and the transient suppressor to burn out for the surge with a wide width. On the other hand, since a resistor is connected in series at the input end, a certain voltage drop is caused. For a high-power type of post-stage ...

AI Technical Summary

Problems solved by technology

On the one hand, this circuit has a certain effect on the peak with a narrow pulse width, but it often causes the resistor and transient suppressor to burn out for a surge with a wider width

On the other hand, since a resistor is connected in series at the input end, a certain voltage drop is caused. For a high-power type of post-stage circuit, if a larger resistance value is used, it will inevitably cause a large voltage drop and affect the normal operation of the circuit. and efficiency; if a smaller resistance value is used, when the high-voltage surge arrives, it will cause a great impact on the subsequent circuit and transient suppressor, and the reliability of the protection is too low

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