Overcurrent protection circuit

A technology of overcurrent protection circuit and current detection circuit, which is applied in the direction of emergency protection circuit device, circuit device, emergency protection device with automatic disconnection, etc. It can solve problems such as protection circuit malfunction and working circuit interference, so as to ensure normal operation , avoid peak interference, and facilitate the process of action

Inactive Publication Date: 2008-11-19
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, in actual work, due to the interference of the working circuit, especially the spike interference of the current, or the instantaneous current spike caused by the instantaneous start-up of the equipment, it may cause the malfunction of the protection circuit.

Method used

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  • Overcurrent protection circuit

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Embodiment Construction

[0016] The present invention will be further described below in conjunction with accompanying drawing.

[0017] combine figure 1 The overcurrent protection circuit of this embodiment includes a current detection circuit 1 composed of a current transformer whose output voltage has a linear proportional relationship with the current flowing through the device or equipment to be protected. The reference voltage Vref and the voltage comparator U1 The voltage threshold discrimination circuit 2 composed of resistors R1 and R2, the delay circuit 3 composed of transistor Q and capacitor C1 is composed of a 555 time base integrated device, light emitting diode D1, resistors R4 and R3, capacitors C2 and C3, single pole A trigger and recovery circuit 4 composed of double-set buttons, and a protection push circuit 5 composed of relays. The current transformer output terminal of the current detection circuit 1 is connected to the first input terminal of the voltage comparator U1 of the vo...

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Abstract

The invention discloses an over current protection circuit which includes a current detecting circuit, a voltage threshold judging circuit, a delay circuit, a triggering and recovering circuit and a protection push circuit. The current detecting circuit is connected with the voltage threshold judging circuit which is connected with the delay circuit; the delay circuit is connected with the triggering and recovering circuit which is connected with the protection push circuit; and the protection push circuit is connected with the device or equipment being protected. In the real working, the over current protection circuit of the invention can avoid the misoperation of the protection circuit due to the interference by the working circuit, especially the sharp peak current interference, or by the instant current sharp peak generated in the instant startup of the equipment. The action process of the invention is convenient, safe and reliable, and can ensure the equipment to work normally under the existence of current sharp peak interference and instant startup of the equipment.

Description

(1) Technical field [0001] The invention relates to an electronic circuit technology, in particular to a protection circuit for current overcurrent in an electric device. (2) Technical background [0002] In electrical equipment, some devices or devices, when the current is greater than a certain value, may cause the device or device to burn or fail to work normally, so it is necessary to protect these devices or devices from overcurrent. In actual work, on the one hand, when the load is zero, such as an output short-circuit fault, a considerable current flows through the transistor, and at this time the transistor withstands a large voltage, which causes the power the transistor can withstand to exceed the transistor’s capacity. The maximum power will cause the transistor to burn out, such as high-power triode, high-power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), IGBT (insulated gate bipolar transistor) and other transistors used for voltage regulation, be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H3/093
Inventor 王华
Owner HARBIN INST OF TECH
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