LM317 overload indicator

[tip35]

Hello ! I am working at a LM317 power supply (tracking preregulator) and I found on the internet a schematic for overload indicator, which I added into my simulation and into my test circuit. After simulating, I found that the Base current of Q9 has spikes of about 4.5-5A, which I think that is very high for a BC327. By adding a 100R (R26) resistor into Q9's base results into a lower value current. Please find below the schematic of the circuit and the simulation results (1st result is with R26=100R and 2nd with R26=0R).
Are any other modifications needed ?
Can R26 value be as high as 1k ?

Schematic:


High current spikes from BC327 base:


Adding 100R resistor in BC327 base:

 

[danadakk]

Looks like it was looking into charging current for C7. Then maybe 317 was
going into thermal limit so current was scaled back ....?


Regards, Dana,

 

[tip35]

You are right, if I modify C7 series resistance, then the current from BC327 base modifies as well.
I am not sure if LM317 was going into thermal limit...