Whenever I am travelling from one place to another, I used to keep my electronics with me. And sometimes to test even the simplest circuits made of few components multiple voltage levels, wires and USB voltages are required. I can not carry my bench power supply with me, that’s why previously I designed a modular portable power supply which is good to go with and has some voltage testing points. But as the circuit complexities increase it can not deliver that much power and overall I need a rigid easy to use power supply unit.
Details
Whenever I am travelling from one place to another, I used to keep my electronics with me. And sometimes to test even the simplest circuits made of few components multiple voltage levels, wires and USB voltages are required. I can not carry my bench power supply with me, that’s why previously I designed a modular portable power supply which is good to go with and has some voltage testing points. But as the circuit complexities increase it can not deliver that much power and overall I need a rigid easy to use power supply unit.
This is the newly designed portable power supply, I followed the 5v boosting approach in this design. So that I can charge the power supply anytime with a standard USB C/A charger. Overall the design is minimalist, looks good and carries 2S 18650 battery for the power backup. This project is sponsored by PCBWAY, China based PCB manufacturer having 10 years of experience in working with PCB related products. PCBWAY is a one stop solution to all your prototyping requirements including SMT assembly, Stencil, 3d printing and metal CNC.
Features:
5V input battery charging feature
Multiple output voltages 12V, 8.4V, 5V, 3.3V and USB
The full circuit diagram can be seen below, the circuit is divided into small sections based on applications. I follow the top to down/ left to right approach, the input is placed on the top left and output at bottom right side.
First section is the main type C input section which is used to charge the onboard 2s 18650 battery. The charging IC is placed in the middle (TP5100), 2S batteries need a max of 8.7V for battery charging. For this the voltage from the TYPE C USB is first boosted to 8.7 and then given to the battery charging unit. I used a 2S battery, two 4.2 batteries in series to get the stable 5V and 3.3V without any drop. In this way the full potential of the voltage regulators can be utilized. A 12V output voltage source is also required for other high voltage applications which is boosted from 8.7V from a second voltage booster section.
PCB Design Considerations:
Because it is a power supply board, it does not carry any differential pair or very high speed tracks across the PCB. Only a few boost conversion frequency generator small tracks which can be traced over a 2 layer stack-up easily keeping ground pour and returning paths in mind. I keep the input and output section away from each other. The 18650 2S battery is mounted on the bottom layer with battery holders.
All the SMD parts are mounted on the top layer of the PCB. The booster section produces unwanted noise frequency, so keep this section away from the voltage regulator and battery charger section. High speed tracks are kept smaller and not overlapped with any other track. Avoid using via while routing for High speed frequency tracks. Ground pour is used on both sides, stitched together via through holes on the PCB. On the silkscreen you can find some test points to see the required voltages availability.
Assembly Process of PCB:
I used the PCBWAY SMT assembly process to get the soldering and part placement done easily. All the components are mounted on the top layer which lower down the overall cost. Some of the general parts are kept as DO NOT PLACE, and soldered by me after receiving the board.
To lower down the cost you can solder the available parts yourself. Because the PCB has a lot of small components...
Lithium ION
