Desktop Power Supply Umbilical With USB-C

My work bench can get covered in wires leading from test circuits to test equipment. This is an idea to cut down on the number of wires draped over the bench by running a single pair of supply cables from the main power supply to a small box placed next to the test circuit.

It's intended to also be portable and be used with other power sources such as 12V car or motorhome batteries or any USB supply.

Features are:

1. Both banana sockets and Dupont pin sockets are provided for connectivity
2. Power supply from a bench top power supply or USB-C
3. Additional posts extending the original supply
4. Fixed 3V3, 5V and 12V supplies for general logic circuits
5. A small voltmeter for casual voltage measurements

The console and basic frame were designed on TinkerCAD here

XL6009 buck-boost module

2 x LM2659 buck module

Schottky Diode 3A

USB-C PT adapter

Cheap voltmeter module - optional but included in 3D print design

Matrix board offcut 50mm x 105mm with tracks running along the length - see construction pictures

A suitable box for your constructed version or plywood base as shown

3D printed parts to hold the components - but not essential, the idea stays the same

The design is relatively simple being a collection of off the shelf modules. Originally it was going to use standard voltage regulators but first tests showed that these were going to be inadequate alone and could get hot even in basic use.

The LM2596 and XL6009 modules are very efficient and can supply more current than a simple regulator setup provided the original supply is adequate.

The USB-C module is included to support usage from now common USB charging bricks or even USB equipped wall sockets.

The output from the XL6009 in this design is 12V and intended to support Arduino supplies and many robot driver circuits. However it can be adjusted to whatever is required such as 9V for battery simulations

The 5V and 3V3 supplies are for very common digital circuit support. A passthrough socket is added to allow access to the supply voltage direct, either as a supply or to feed the voltmeter input.

The voltmeter provides a reading of any of the supply voltages should that be required, or from the circuit in use.

Four components have been designed, a front console for the sockets and meter, a bracket to support the modules and two side legs to hold the console above the modules.

A case has been designed for completeness but it is envisioned that the constructor will make one to suit the components and circumstances of their own use.

The design is available on TinkerCAD

The console has been designed to support matrix board of 2.54mm or 1/10 inch hole spacing

The board has been cut down to approximately 105 x 30mm in size, with a cut out for the voltmeter.

When fitting the PCB header sockets, first fit the matrix board to the console and test fit the headers, then mark through the holes where they fit.

When soldering the headers to the board, they can be held manually or aligned using strips of PCB pin and socket headers to align them. Before soldering all connections, test fit the board to the console.

Once soldered in place, fit the board to the console and drill holes through the board for the banana sockets using an appropriately size drill for your sockets, in this case 5mm, using the console as a drill guide. While doing this the board can be supported with a small offcut of wood.

Test assemble the console to ensure everything fits, and if the legs are being used, mount them together and test the clearance on the module board. Some banana sockets can have long mounting bolts which can foul the modules, so either be prepared to cut these shorter, or position the board appropriately. Ultimately the support legs can be lengthened to accommodate long banana sockets.

Before soldering the console, cut the tracks on the board to prevent short circuits. See the diagram for where these cuts need to be. Depending on the type of matrix board used, more or less cuts may be needed.

This consists mainly of inserting 3mm bolts through the base of the frame and then attaching the modules via nuts. The USB-C module is slid into the mounting slot with the USB socket facing out but this should not be done until the power wires have been soldered as the module will lock in place when inserted fully.

To simplify wiring, position the modules in the same orientation as the circuit diagram

A case is suggested in the TinkerCad source design, but for the purpose of a general test circuit it has been left as a skeleton build. A small piece of plywood has been drilled and the module board and console supports bolted to it.

The wires have been colour coded in the picture to help identify the different connections. It is recommended that the connections to the power modules is done first and then test these for continuity.

As this is optional it has been given its own step. It is also worthwhile doing separately from the main wiring to make the connections clearer.

Measure and cut the wires to length, tin each one. The yellow wire is soldered to the two pin socket next to the display. The red and black power wires are soldered to the regulated positive from the xl6009, and the ground respectively

Once complete, bolt the console to the support legs, taking care to tuck the wires underneath.

The unit can be used in may ways, examples of which might be:

1. A connection to a desktop power supply using banana plugs and leads
2. A connection to a 12V battery with banana plugs and cigarette plug or crocodile clips
3. A connection to a USB-C connection with PT
4. A standard USB socket
5. A portable USB equipped power pack.