This is an over-current trip switch. It provides protection to a load when over current condition occurs. Basically, the project trips the relay when there is a short circuit or the load starts drawing much current. When the condition is favorable, press the tactile switch to power the load again. The threshold voltage of the comparator is 0.6V, the over-current limit can be adjusted using the trimmer Potentiometer PR1. Operating supply 12V DC @ 80mA when the relay is ON, load supply 0V to 48V.
This is an over-current trip switch. It provides protection to a load when over current condition occurs. Basically, the project trips the relay when there is a short circuit or the load starts drawing much current. When the condition is favorable, press the tactile switch to power the load again. The threshold voltage of the comparator is 0.6V, the over-current limit can be adjusted using the trimmer Potentiometer PR1. Operating supply 12V DC @ 80mA when the relay is ON, load supply 0V to 48V.
The project is built using INA202 chip from Texas Instruments. The INA202 chip includes the high-side current-shunt monitor with voltage output and an integrated comparator. The device measures current through the shunt resistor R1 with current flowing in one direction that enables detection of an overcurrent event only when the differential input voltage exceeds the threshold limit. When the current reaches the set limit of the divider R7/ PR1, the output of CMPOUT transitions high, which turns Q1 on, pulls the base of the BJT transistor Q2 low which then switches OFF the relay, and turns the flow of the current OFF through relay contacts.
Trip Current Threshold
Trip current is adjustable from 250mA to 3A, PR1 trimmer potentiometer is provided to adjust the trip current, and load supply range is from 0 to 48V.
This project can be used for higher current trip and higher Voltage load with a few changes. Please refer to Datasheet for more details.
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