Relay Coil Open Circuit Fault Detection Circuit

Abstract

The invention discloses a relay coil open-circuit fault detection circuit, which includes a diode D1, a diode D2, a resistance R1, a resistance R2, a switch tube and a single chip. The anode of the diode D1 is connected with a relay power supply voltage Vcc through a relay coil J, the cathode of the D1 is grounded through the switch tube, and the two ends of the diode D1 are in parallel connectionwith the resistance R1; the cathode of the diode D2 is connected with the anode of the diode D1, the anode of the D2 is connected with a reference voltage Vref through the resistance R2, the common node of the diode D2 and the resistance R2 is used as a test point Vs, and the test point Vs is connected with an AD port of the single chip. According to the relay coil open-circuit fault detection circuit, the AD port of the single chip is used for collecting the voltage of the test point Vs to identify three states of a relay of breaking, closing, and closing but coil opening, and the voltages of the test point Vs of the three conditions has a big difference and can be clearly identified; detection results are efficient and accurate, the circuit structure is simple, and the cost is low.

Description

technical field [0001] The invention relates to a relay coil, in particular to a relay coil open-circuit fault detection circuit. Background technique [0002] The relay is a commonly used electrical control device. It is an electrical appliance that causes the controlled quantity to undergo a predetermined step change in the electrical output circuit when the change of the input excitation quantity meets the specified requirements. It has the interactive relationship between the control system or input loop and the controlled system or output loop. Usually used in automatic control circuits, relays are often used in actual circuits as an "automatic switch" to control large current operations through small currents, and are widely used in many occasions, such as automotive electronic control components, relays are used To effectively protect and control the on-board electrical appliances, it plays the role of automatic adjustment, safety protection, conversion circuit, etc....

AI Technical Summary

Problems solved by technology

[0003] However, the existing automotive relays only detect and test the on-off of the relay contacts before leaving the factory, and the relay itself does not have self-detection of the on-off state and fault state, and this is undoubtedly the reason why the relay is put into practical use as an electrical control device. After that, it is difficult to realize its own self-detection on-off and fault status, which is easy to cause circuit faults, and when the control circuit fails, it cannot quickly and accurately determine the location of the fault point, which brings delays to circuit fault detection. Not conducive to the maintenance of the entire control system

However, due to specific conditions such as high temperature, sealing, and high speed around the relay, the inspection of the relay coil is extremely cumbersome, and puts forward higher requirements for the technical level of the inspection personnel.

Therefore, the biggest disadvantage of manual maintenance is low efficiency, inaccuracy, untimely service, misjudgment and other problems, and waste of labor and low work efficiency

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