A delay start overcurrent protection circuit

A technology of overcurrent protection circuit and delayed start, applied in emergency protection circuit devices, emergency protection devices with automatic disconnection, circuit devices, etc., can solve the problem of inability to act immediately, and achieve rapid response, simple structure, and versatility. strong effect

CN104836196BInactive Publication Date: 2018-03-16XUJI GRP +2
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2018-03-16
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention discloses a delayed start overcurrent protection circuit, which includes a controlled switch circuit, a sampling circuit, a control circuit and a controlled switch circuit, the control circuit includes a comparison output unit and a delay unit, a comparison output unit and a delay unit The output ends of both are connected to the control end of the controlled switch circuit; the comparison output unit is used to compare the sampled voltage value obtained by the sampling circuit with the preset first reference voltage, and control when the sampled voltage value is higher than the first reference voltage The controlled switch circuit is disconnected; the delay unit is used to clamp the voltage signal at the control terminal of the controlled switch circuit when the sampled voltage value is higher than the first reference voltage, so that the sampled voltage value is lower than the first reference voltage after the controlled switch circuit is disconnected voltage to prolong the off-time of the controlled switching circuit. The circuit responds quickly and has a time-delay function, that is, when an overcurrent occurs, the switching circuit is quickly shut down and has a certain recovery time, and has the characteristics of simple structure, low cost and strong versatility.
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Description

technical field

[0001] The invention belongs to the technical field of circuit design, in particular to an overcurrent protection circuit with delayed start. Background technique

[0002] Overcurrent protection is also called overload protection. Overload means that the load is too large, exceeding the rated load of the device itself. The phenomenon of overload is that the current is too large, and the electrical equipment heats up. The long-term overload of the line will reduce the insulation level of the line, or even burn the equipment or line. Therefore, the corresponding equipment should be protected by an over-current protection circuit, and a reasonable over-current threshold should be set in the over-current protection circuit.

[0003] The overcurrent protection circuit disclosed in the prior art generally includes a sampling unit, a comparison unit, and a control unit. The sampling unit is used to sample the real-time current of the loop and convert it into a real...

Examples

Embodiment Construction

[0018] The present invention will be further introduced below in conjunction with the accompanying drawings and specific embodiments.

[0019] Such as figure 1 Shown is the functional block diagram of the overcurrent protection circuit with delayed start of the present invention. It can be seen from the figure that the circuit includes a controlled switch circuit and a sampling circuit for connecting in series with the electrical equipment, and the power supply terminal of the electrical equipment is connected to the power supply; The signal output terminal of the sampling circuit is connected to the control circuit, and the output terminal of the control circuit is connected to the control terminal of the controlled switch circuit. The control circuit includes a comparison output unit and a delay unit, and the output terminals of the comparison output unit and the delay unit are connected to the The control terminal of the controlled switch circuit is connected; the compariso...