13 January 2015

A variable PSU with LM2596 adjustable DC-DC step-down regulator?

Now that I have a lab PSU with an adjustable regulator inside, how about bringing the voltage control to the front panel?

The voltage regulator module is based on LM2596-ADJ and sells for ~3 USD@2015. Output voltage is controlled via a 10 turns 10kohm trimpot.

The datasheet says that the adjusting resistor must be connected as close as possible to the LM2596 (and away from the inductor). Moreover it is completely floating off GND, so any modification is out of question.

It is better to look for a different step-down adjustable circuit, or use a long shaft to bring the control to the outside. Nevertheless, multiturn trimpots are not meant for daily usage, but rather for a one-time set-and-forget application.