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Integrated Regulated power supply
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techguru:
Hi to all,

                I found this circuit in internet, please explain the variable current limiting function in LM723 IC?

Thank you all..
jeroen79:
http://www.ti.com/lit/ds/symlink/lm723.pdf

The built in current limiter consists of a single transistor that with it's collector connected to the output transistor's base.

Parallel to this transistor's base and emitter is the current sense resistor.
When the voltage drop over that resistor exceeds 0.6V the base will start to draw current, turning the transistor on.

This transistor will then draw current away from the output transistor's base, reducing the output current.

Interestingly, in this circuit they put the current sense resistor on the low side, rather than on the high side.
techguru:
I think there is a error in Schematic. Check this . I have attached the circuit, with red color to mark the error.
techguru:
How does this make Current limiting function?

               I have calculated node voltages at each node. now my current sense transistor will experience 6.35v or 5.6V in its base and 0V at emitter at no load condition .  This will damage my current sense transistor, Is it correct??

Please clear my doubt...
DC1MC:
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