Protective circuit based on PTC thermistor

A thermistor and protection circuit technology, applied in the direction of emergency protection circuit device, emergency protection circuit device, circuit device for limiting overcurrent/overvoltage, etc., can solve the problem of high temperature, thermal breakdown, limited varistor and other problems, to achieve the effect of low cost, improved reliability, and improved safety performance

Inactive Publication Date: 2013-12-18
WUHAN LIANCHUANG HENGYE SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the ZnO varistor absorbs energy when it is turned on, and its own temperature rises rapidly. Therefore, the energy that the varistor can absorb when it is turned on is limited. If the energy is too large, the temperature of the varistor will be too high and be damaged. thermal breakdown failure

Method used

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  • Protective circuit based on PTC thermistor

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Embodiment Construction

[0013] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

[0014] like figure 1 As shown, the protection circuit based on the PTC thermistor according to the embodiment of the present invention includes: a zinc oxide varistor 1 , a PTC thermistor 2 , a thermal fuse 3 and a circuit to be protected. After the protected circuit is connected in parallel with the zinc oxide varistor 1, it is connected in series with the PTC thermistor 2 and the temperature ...

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Abstract

The invention discloses a protective circuit based on a PTC thermistor. The protective circuit based on the PTC thermistor comprises a zinc oxide piezoresistor, the PTC thermistor, a temperature fuse and a protected circuit, wherein the protected circuit and the zinc oxide piezoresistor are connected in parallel and then are connected with the PTC thermistor and the temperature fuse in series. According to the protective circuit based on the PTC thermistor, overvoltage protection, overcurrent protection and overload protection can be achieved at the same time, thermal runaway, caused by over-high temperature, of the thermistor is effectively avoided, potential safety hazards which are caused by the potential failure mode of the PTC thermistor are effectively avoided, safety performance is improved, the protection speed of the PTC thermistor is improved, influence of environment temperature on the protection speed of the PTC thermistor is reduced, the circuit structure is simple and cost is low. The protective circuit based on the PTC thermistor is suitable for being popularized widely.

Description

technical field [0001] The invention belongs to the technical field of electronic circuits, and more specifically relates to a protection circuit based on a PTC thermistor. Background technique [0002] Positive Temperature Coefficient (PTC) thermistors are widely used in circuit protection in 6C industries such as computers, communications, consumer electronics, automobiles, access, and digital content. Its working principle is: when the circuit is working normally, the resistance of the PTC thermistor is very small and does not hinder the flow of current; when the circuit has overcurrent, overload, or overheating faults, the surface temperature of the PTC thermistor rises rapidly, exceeding When switching temperature, its resistance value instantly rises to a high resistance state, which limits the circuit current to a very low level in time to protect the circuit. When the fault is removed, the PTC thermistor cools down quickly and returns to the original low resistance ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H9/02H02H9/04
Inventor 黄淳陈松
Owner WUHAN LIANCHUANG HENGYE SCI & TECH
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