Short Circuit Protection With A MOSFET

Posted on Feb 5, 2014

If you have an application in which a MOSFET is already used to switch a load, it is relatively easy to add short-circuit or overload protection. Here we make use of the internal resistance RDS(ON), which produces a voltage drop that depends on the amount of current flowing through the MOSFET. The voltage across the internal resistance can be sensed using simple

Short Circuit Protection With A MOSFET
Click here to download the full size of the above Circuit.

comparator or even a transistor, which switches on at a voltage of around 0. 5V. You can thus avoid the use of a sense resistor (shunt), which usually produces an undesirable extra voltage drop. The comparator can be monitored by a microcontroller. In case of an overload, the software can initiate suitable countermeasures (PWM regulation, alarm, emergency stop etc. ). It is also conceivable to connect the comparator output directly to the gate of the MOSFET, in order to immediately cut off the transistor in case of a short circuit.

Leave Comment

characters left:

New Circuits



Popular Circuits

Electronic Candle Blow Out
Pocket-sized geiger counter
Shortwave Converter For Am Car Radios
VU and PPM Meter Circuit for Audio
Simple Light Sensor Alarm circuit with NE555
touch sensor switch using inverters
dm projects
50 Watt Amplifier
Z80-Family Official Page
Integrated OCL power amplifier circuit composed by the TDA2040