Hello

Following to my previous question about making a circuit that allows adjustable voltage output and current limiting, and using LM2596 I was able to limit the current for the positive voltage using the circuit:



But I am having troubles with the negative voltage, and it doesn't work:



Need help what am I doing wrong, or maybe it can't be done?

 

With out commenting on the current limit circuit:
See the red traces. They are not "ground" but -V. The opamp and RV1 and RV2 need to be connected to -V.
People often forget how to connect Vin. I believe it is connected as shown in blue. D3a to (0V)
Hope this helps. RonS.

 

With out commenting on the current limit circuit:
See the red traces. They are not "ground" but -V. The opamp and RV1 and RV2 need to be connected to -V.
People often forget how to connect Vin. I believe it is connected as shown in blue. D3a to (0V)
Hope this helps. RonS.
View attachment 318166

Hey RonS

Thank you very very much, the negative voltage is working now!.

Now need to figure out the current limiting part.

 

Now need to figure out the current limiting part.

See the Current Limit Adjust pin on the LN2673-adj. It is a newer version of the part.

 

See the Current Limit Adjust pin on the LN2673-adj. It is a newer version of the part.
View attachment 318262

Thanks again..

I cam across this IC, but unfortunately it doesn't have a negative output setting like the lm2596..

 

From application note AN-1175