During start up of a very simple LM7915 LDO within a split supply system for +/-15V sometimes ADJ-Pin Current increases during start up phase above the usal level.
When this occurs, LM7915 can hang at 0V output voltage.
As soon as adj pin current returns to usal values, output voltage recovers as well.
So what IC structure is causing this current increase and latching of LM7915?
How to prevent this reliably and not just by try and error and hope?
Note on attached image:
CH4 voltage is proportinal to ADJ-Pin current. The current before division 1 is in higher level with a voltage level of ~600mV. Once LM7915 starts up ADJ pin voltage level goes back to ~500mV
When ADJ-Level goes to 500mV LM7915 works as usual
When ADJ-Level stays at 600mV Level LM7915 is hanging at 0V
Or as in picture it first hangs a short time and then recovers.
