I am using a diode to bias a BJT in order to regulate voltage to a load. See attached image (top)
This top circuit in the attached figure works well and this concept of diode regulation cant be changed.
The problem is that if the load fails as an open circuit, all the current is forced through the BJT
The BJT can get very hot, even with a heatsink as there is 7 Volt drop over it.
To be honest, Im not sure why there has to be a drop here but there is.
Id like to come up with a method to bypass the entire BJT if the load open circuits.
An example concept is in the attached image, bottom, but this wont work.
The idea is that the induced voltage drop over a 1V shunt resistor can switch on a JFET.
Of course, it wont work as once the BJT is bypassed, there is no current on this resistor.
It would only work if the FET latched.
Whatever circuit elements are intruded need to be regulated internally, mean, there is only 6.8volts until it bypassed.