Revision 0.3

A project log for VederPSU

A tiny and efficient uC controlled lab power supply

riktwriktw 02/12/2017 at 21:150 Comments

The revision 0.2 board worked mostly, but has a few issues. One was that idiot me forgot to connect 2 pins to the ground. The other issue is that the LT3081's need a bit of load to regulate to 0V and that the 5V regulator used has a maximum input of 20V.

Revision 0.3 fixes these issues.

The 5V regulator has been replaced by a 78L05, the SOIC version of the well known 7805, which is capable of 30V input. Not perfect but acceptable for now. A SMPS would be a nicer solution in the future.

The problem with 2 gound pins not connected has been fixed. A small power LED has been added as well as an indication the device is powered.

At last a LM2687 has been added to generate -5V at a few mA's This is used to create some load for the LT3081's so the output will regulate to 0V. It's afforable and works perfect for this application.

The new files have been added for the schematic and PCB layout.

On a more interesting note, a PCB that will be used as a front panel containing an LCD, 2 rotary encoders and a uC is being designed, this together with the rev 0.3 VederPSU design will make a more complete and functional lab power supply. Hopefully an update will be here in about a month on that.