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Add overvoltage protection to save voltage regulator

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matrixofdynamism:
So there is a linear voltage regulator that I intend to use. However, like everything else, this component also has an absolute maximum voltage level of its input. What is the correct way to protect input of voltage regulator from overvoltage? This shall be connected to a bench powersupply so wouldn't want the circuit to be destroyed.

Now I think, we should be able to add a zener diode that has maybe a breakdown voltage that is just close to the absolute maximum of the linear voltage regulator. However, if this condition was reached, the diode will probably be overheated and destroyed unless there is current limit also applied somehow. I guess in this case, we could add a zener diode to high side, with resistor in series on the low side (to GND) to limit the current. Is this the correct way to create an over voltage protection circuit?

The thing is, I want to add reverse polarity protection along with overvoltage protection. Therefore, if I add zener diode, there is still the issue of what will happen when the polarity is reversed. The reverse polarity can be handled using some FET transistor circuit but I haven't gone far with that  idea yet.

Please let me know if this question has already been asked here and fully discussed.

Jwillis:
 An in line diode is the simplest polarity protection but you'll get a voltage drop from the diode . Or you could use a P Channel Mosfet for better results.

The over voltage protection will follow the polarity protection .

These are ones I've used but I'm sure there are others that may be better.
 

barshatriplee:
Place a series resistor between the input voltage and the voltage regulator's input pin.
Connect a zener diode in parallel with the voltage regulator's input pin.
Choose a zener diode with a breakdown voltage slightly higher than the maximum input voltage of the regulator.
In normal operation, the voltage drop across the series resistor is small, and the zener diode remains in the off state. However, if the input voltage exceeds the breakdown voltage of the zener diode, it starts conducting and clamps the voltage across the regulator's input pin.

G-son:
Zener diode plus fuse perhaps? If input voltage goes above zener voltage the zener will allow a large current to go straight to ground, blowing the fuse.

matrixofdynamism:
Using fuse means that it will be blown and needs to be replaced.

During my search I came across some very phenomenal ICs like one called efuse. Maybe that could be a good option. Adding protection is important since we don't know how the end user will connect the PCB.

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