Over-voltage protection circuit

Abstract

The protective circuit of overvoltage protection is connected between a contact at secondary side of transformer and a load. When voltage at the contact at secondary side is abnormal, the protective circuit can cut off online of load directly to protect the load from damage; when voltage at the contact at secondary side returns back to normal, the protective circuit can resume to supply power to load directly.

Description

technical field [0001] The present invention relates to an overvoltage protection circuit, especially one that is electrically connected between a secondary side contact of a transformer and a load. When the output current of the transformer produces an overvoltage state, the circuit can be directly cut off to protect the load. An overvoltage protection circuit. Background technique [0002] Basically, if you want an electrical device to work normally, you need a voltage source to provide voltage, drive the current to flow through the electrical device, and make the electrical device do work to produce the functions we need; at this time, for To make the voltage source provide an appropriate voltage, the voltage provided by the voltage source can be adjusted by a voltage regulator before it enters the electrical equipment; however, based on safety considerations, an overvoltage protection circuit is often required between the electrical equipment and the voltage source , so...

AI Technical Summary

Problems solved by technology

[0002] Basically, if you want an electrical device to work normally, you need a voltage source to provide voltage, drive the current to flow through the electrical device, and make the electrical device do work to produce the functions we need; at this time, for To make the voltage source provide an appropriate voltage, the voltage provided by the voltage source can be adjusted by a voltage regulator before it enters the electrical equipment; however, based on safety considerations, an overvoltage protection circuit is often required between the electrical equipment and the voltage source , so that when the voltage source has abnormal power supply, it will cause damage to electrical equipment, not only that, but sometimes irreparable damage

[0003] An example of an application of an overvoltage protection circuit is shown in the first figure, which is a functional block diagram of an application of an overvoltage protection circuit, wherein a voltage source 10 is used to provide a voltage, and a primary side contact 151 of a transformer 15 is in Before being connected to the voltage source 10, it will be electrically connected to an interruption circuit 121, and the secondary side contact 152 of the transformer 15 is electrically connected to a load 16 and one end of a detection response circuit 122, wherein the load 16 can be Any electrical equipment, such as a lamp, etc., and its other end is electrically connected to a ground terminal 18, and the other end of the detection response circuit 122 is electrically connected to the interruption circuit 121, so that the interruption circuit 121 and the detection response circuit 122 constitute An overvoltage protection circuit 12; wherein, the detection response circuit 122 is used to detect whether the output voltage value of the secondary side contact 152 of the transformer 15 is abnormal, and if the output voltage value of the secondary side contact 152 of the transformer 15 is abnormal, it is also That is, when the output voltage is higher than a default value, the detection response circuit 122 will generate a signal to notify the interruption circuit 121 to cut off the circuit, so that the voltage generated by the voltage source 10 will not enter the load 16 through the transformer 15, causing damage to the load 16

[0004] The above-mentioned overvoltage protection circuit 12 of the prior art can indeed have the effect of protecting the load 16, but if the voltage source 10 returns to normal, the detection response circuit 122 fails to detect and then resets the interruption circuit 121, so that the load 16 can continue Work, causing troubles for designers, often in order to make the overall circuit have an automatic reset function, and further design the reset circuit, which invisibly increases the number of application components, makes the overall circuit more complicated, and causes a relative increase in cost

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