I am looking at the best method to control an LDO enable pin using a negative voltage current limit circuit. The LDO is disabled when the enable pin is 0 to 0.4V. The LDO is enabled when the enable pin is 2 to 10V (max).
The current limit circuit that i am using is below. R3 models the load. Under normal condition the load current is 0.2mA or less. Under fault conditions the load current is 2mA.
The basic idea is that the LDO is disabled (LDO enable pin 0 to 0.4V) when the load current reaches 2mA. Under 2mA the LDO is enabled (LDO enable pin 2 to 10V (max)).
Apart from the -32V input there is also 3.3V.
Look forward to your replies.