Power broadband short-circuit protection circuit of pulse tracking type

Abstract

The invention relates to a power broadband short-circuit protection circuit of a pulse tracking type, and the circuit comprises a first signal detecting circuit N+ sampling point composed of R1, R4 and C1, and a second signal detecting N- sampling point composed of R2, R3 and R5, wherein the two channels together constitute pulse signal tracking detection. The N+ and N- channels of the signal tracking detection output are respectively connected to the non-inverting input end + and the inverting input end of a voltage comparator C, and the output end of the voltage comparator C is connected tothe control electrode of a contactless switch Q via a R6 resistor. A resistor R7 is connected in parallel to both ends of the contactless switch Q, that is, the negative pole V- of the power supply and the load -V serve as an automatic recovery device after the load short-circuit fault is eliminated. The pulse voltage generated by the load short-circuit fault is used to quickly turn off the faultload, and the sensitive and reliable power supply short-circuit protection circuit with a wide voltage range can be realized. The power supply loop does not have a series circuit current sampling resistor or inductor, thereby reducing the generated heat and improving the power supply efficiency.

Description

technical field [0001] The invention relates to a pulse tracking type power supply short-circuit protection circuit with a wide range of voltage adaptation, in particular to an intrinsically safe power supply short-circuit protection circuit. Background technique [0002] According to the requirements of national standards, in environments containing explosive mixtures such as petroleum, chemical, textile and coal, as power supply equipment for communication, monitoring, detection, alarm and control systems, in order to prevent sparks generated when the power output is over-current or short-circuited For flammable and explosive gases, protective circuits must be used to limit the energy released by sparks. [0003] Intrinsically safe power supply refers to intrinsically safe power supply. In the design, the output voltage, current and power of the power supply circuit are fully considered, and the protection work is done well to prevent the spark generated by overvoltage or ...

AI Technical Summary

Problems solved by technology

[0004] The above commonly used power supply protection circuit has the following deficiencies: First, the action voltage range for detecting the comparison potential will narrow with the change of the input voltage. After the action voltage is adjusted, if the input voltage and current are changed, the original action of the comparison potential will be affected. Even cause the protection circuit to malfunction or fail to operate

The second is that there must be a detection resistor or inductance in the circuit. The detector with a large resistance value is sensitive and easy to adjust, but the resistance of the resistor will increase due to heat and cause a voltage drop, making the voltage at the load end lower. Therefore, the only way to do this is to increase the voltage at the input end. If inductive detection is used, the volume is large and the cost is high

The third is that the action range is too narrow when a fault occurs, because it is determined by the voltage ratio of the detected comparison potential. If the ratio is large, it is not easy to operate, and if the ratio is small, it is easy to malfunction, which makes the stability and anti-interference ability worse.

Fourth, it is not easy to automatically restore the power supply after the fault is eliminated, so it cannot automatically restore normal operation when the load is large, which brings great trouble to debugging.

Fifth, in order to solve the deficiencies in the four aspects, only a more complex circuit structure is added, so that the production cost is increased, and the failure rate of the whole machine is also greatly increased

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