Low Voltage DC Load Break Monitoring Circuit

Abstract

The invention relates to a low-voltage direct-current load open circuit monitoring circuit comprising a reversed polarity voltage stabilizing circuit and an open circuit alarm circuit. The low-voltage direct-current load open circuit monitoring circuit specifically comprises a direct-current driver DR1, a direct-current load DL1, a reversed polarity chip IC1, an optocoupler IC2, an inductor L1, a transistor Q1, a switching diode D1, a monitoring diode D2, a light-emitting diode LED1, an experimental switch L1, an input capacitor C1, a current-limiting resistor R1, a lower feedback resistor R2, an upper feedback resistor R3, a pull-up resistor R4, a base resistor R5 and the like. According to the invention, based on the reversed polarity lifting and lowering type DC / DC conversion electricity utilization on a direct-current driving power source and by using the clamping function of the diodes to perform open circuit judgment, the low-voltage direct-current load open circuit accurate monitoring can be realized without using a current sensor to directly detect the magnitude of the direct-current load current. According to the invention, advantages of simple structure, convenient utilization, safety, reliability and low cost can be realized.

Description

technical field [0001] The invention belongs to the field of industrial measurement and control, and relates to a circuit, in particular to a low-voltage DC load break circuit monitoring circuit, which is suitable for occasions where low-voltage DC load break circuit faults need to be monitored. Background technique [0002] When using a DC drive power supply to power and control low-voltage DC loads, the load is often far away from the DC drive power supply. Therefore, it is often necessary to judge whether the load is connected or not and to monitor possible load-side open circuit faults. The current commonly used method is to detect the load current through a Hall current sensor or a current sampling resistor and convert it into a voltage signal proportional to the current. The signal is compared with a zero current reference signal by a comparator. When an open circuit occurs, Signal a logical alarm. The problem with this method is: when many loads are in a light-load s...

AI Technical Summary

Problems solved by technology

The problem with this method is: when many loads are in a light-load state, the load current is very small, so that the voltage signal output by the current sensor is also very small, and the sensor output drift and the conversion circuit signal that exist objectively Noise, etc., will easily lead to false alarms for open circuits

In addition, the solution based on the Hall current sensor is expensive; while the solution based on the current sampling resistor has a complex isolation circuit structure

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