Main Question or Discussion Point
I am making a totem pole digital output of 1.5-23v. i was searching for a protection circuit for the output short to ground and +24v dc. please help me out by sending a diagram of the circuit if possible.
I can protect V3 easier. Put a resistor R5 between the emitter of V3 and V5. Put 3 diodes D1, D2 and D3 in series with cathode of the D1 connect to the base of V3. The anode of D3 to the output. This will serve as current limiting. If you have a short from output to the ground, then you draw excess current from V3. The excess current will create a voltage drop across R5. As soon as there is 0.7V drop across R5, the voltage from base of V3 through V5 will be over 3 diode drop and D1 to D3 will turn on and start pulling current from the base of V5. This will serve as current limit. The value of R5 can be set depending on the maximum current you want to allow V3 to source.uploaded a jpeg version.