As a maker myself and a person that likes to tinker with lot of new and old electronics IC and devices, I came across a lot of situations where I wanted to have reliable source of power with some kind of protection that can help me safely debug or power my electronics.

The best way to test SMT and THT components or self-made circuits is by using a bread board .

When I scouted the market both online and offline, I came across many bread board power supplies but they all lack the protection circuit, even some of them do not have reverse voltage protection and most off them take a considerable amount of space on the breadboard which make it hard to work.

So, I decided to make a breadboard power supply that can have both power rail 5V and 3.3V and over current protection and a reverse voltage protection unit. The main goal was to create a user-friendly, low-cost breadboard power supply with a very low footprint and which gives user an ability to set the over current protection threshold for both the power rails (5V and 3.3V). Normally breadboard power supply comes with a barrel jack but now days every one has USB power brick so I decided to power it all up with a TYPE C connecter. 

Step 1

Let's now make a breadboard power supply with all the feature mentioned above so for starter we will use a TYPE C connecter to power up our power supply. CC1 and CC2 pins of the type c connector is connected to a 5.1K resistors to advertise its current carrying capacity. then a M7 diode is used as reverse voltage protection.

A LED is used to indicate power with a 1K current limiting resistor then the power goes to the 3.3V regulator (AMS1117).

Step 2

For the over current protection, I wanted to go with some kind of solid-state system rather than using a relay which is big and takes a lot of space so I started to searcher the internet firstly I came across E-fuses which are good for the purpose that I was looking for but the cost was high and they do not have adjustable over current protection as intended 

Then I came across an IC made for the purpose, MT9700 solved the purpose which comprises of a small package and all the feature needed and the cost is also low 

Step 3

To make the power supply dual rail an SMD switch is used that can either connect the 5V to the output or the 3.3V through the regulator at the output a LED is also given to show the output power and it goes off when a short circuit or over current is detected. 

Step 4 

To set a suitable value of the output current protection a resistor is used in the this configuration

                                                           PIC TAKEN FORM DATASHEET 

In this power supply R2 resistor is used to set the over current limit of the power supply unit, For 10K value of R2, the power supply gives an output current  of about 750 mAmps.

FOR BETTER UNDERSTANDING OF THE POWER SUPPLY ALL THE COMPONENTES ARE MARKED 

Step 5 

Now as we have discussed all the working components  used in the power supply we can go ahead and create a schematic of it and then make a PCB out of it .

Schematics 

I have created the schematics using the datasheets of the components that we used like MT9700, AMS1117, TYPE-C connector. I have used DIPTRACE software to create the schematic as well as PCB, Schematics of the project is attached, please feel free to modify it according to your needs.

PCB 

According to this schematic I create the PCB for the power supply and also connect the headers to the PCB's for debugging and testing.

TOP PCB 

BOTTOM PCB

GERBER FILES FOR PCB ARE IN ATTACHMENTS 

THE SIZE OF THE PCB WITH THE END RAIL CONNECTOR IS 53mm BY 22.5mm

3D view 

In DIPTRACE software we can also check how the PCB will look when its done Soldering of all components in 3D viewer  

TOP PCB

BOTTOM PCB 

SIDE VIEWS

After completing the pcb file, the Gerber is generated through the software which is used to order pcb online through the vendor, In this case I used JLC pcb to order the PCBS.

Step 6

Soldering

After you get the PCB you can start soldering the components in their places and test the circuit

After soldering

TOP PCB 

BOTTOM PCB 

Step 7

Testing 

WARNING- when the short circuit protection is triggered MT9700 can get very hot it may damage the part  

Conclusion

At last you can now use the universal power supply to test your IC or circuits when needed 

HAVE FUN!!!