This is part of a larger circuit, but problem area is shown below. In simulations (of the larger actual circuit not shown), the base voltage of Q1 drops to about -6.35V. Can this damage Q1 (2N3904)? What if the base voltage drops to -15V? Current flowing through emitter base with base at -6.35V is in pico amperes (~25pA).
If this is a problem, how can I limit base voltage between 0 and -5V, without limiting op amp supply voltages?
PS: This is for a bench power supply. I need a +15V since there is a differential amplifier for voltage sensing and I lose accuracy at low output voltages if op amp +V supply is low. The -15V tracks the +15V, otherwise I lose accuracy at low voltages and current sensing (due to greater offset).