Logic Power Supply circuit with Overvoltage Protection

Here the simple 5V regulated power supply circuit which featured overvolatage protection.

The circuit work:
This circuit uses the crowbar method, where a thyristor is employed and short circuits the supply, causing the fuse to blow. This will take place in a few microseconds or less, and so offers much greater protection than an ordinary fuse. If the output voltage exceed 5.6Volt, then the zener diode will conduct, switching on the thyristor (all in a few microseconds), the output voltage is therefore reduced to 0 volts and sensitive logic IC's will be saved. The fuse will still take a few hundred milliseconds to blow but this is not important now because the supply to the circuit is already at zero volts and no damage can be done. The dc input to the regulator needs to be a few volts higher than the regulator voltage.

Read more circuit explanation at http://www.zen22142.zen.co.uk/Circuits/Power/overvolt.htm

Comments

Unknown said…

I am familiar to crowbar method which I personally feel easy to use it. The solution to the problem in the circuit is shown in a good manner and with the circuit our work gets quite easy to understand the whole concept.

power supplies

October 4, 2010 at 12:15 AM

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