I am trying to design a current limiter that limits current through R4 based on a typical transistor-MOSFET topology like the one in the picture:
This circuit works fine. When the voltage accross R3 is Veb (0.65) current begins to be limited (at 0.25 amps) by means of the MOSFET.
The problem is that I want to limit the current from a negative voltage source. For example, if VS1 would be -5V or -10V. Of course, then the current flows in the opposite direcction and the circuit does not work. I've tried changing both transistors (to npn and Nchannel) without success. Also I tried changing the arrangement of components (bipolar circuit to the right and MOSFET to the left), also without success.
Could you hint me how to arrange components to obtain my goal? Thanks
PD:Other topologies are also accepted. PD2: No ICs if possible