Portable Power Supply Unit

Last Updated on March 16, 2024

Every electronic circuits need power source to operate, for electronics Engineers and Electronics makers it is necessary to possessing ready to use power source for prototype and testing electronics. Following design propose a reliable and easy to carry portable power supply unit. Final output of this circuit can be varied from 5V to 26V. Li-ion Battery in this circuit can be charged through AC input and also USB power from gadgets charger or other power sources.

Portable Power Supply Unit circuit designed to help testing and trouble shooting during movement and also in power cut situations. You can reduce the size of this design by removing AC to DC Rectifier section. Then you can charge by using through USB only. Here you can learn How the USB Works?

Portable Power Supply Unit Design

This design contains four blocks in a compact space, here the Lithium Ion battery 3.7V – 2000 mAh used as a Rechargeable power source. Rectifier circuit converts 230V AC input to 5V DC output by Stepdown transformer and positive voltage regulator IC 7805 and USB to Lithium battery charger module gives DC supply to battery, both inputs are controlled by the DPDT slide switch and DC-DC boost converter module gives 5V to 26V DC from Li-Ion battery.

Portable Power Supply Circuit

Construction and Working

As per the design Rectifier circuit constructed using discrete components and it takes 230V AC as input and gives 5V DC as output and the output connected to the A1,A2 pin of Slide switch. TP4056 mini USB – Lithium battery charger module takes Input from mobile charger or USB power sources and gives constant current charging supply to Li-Ion battery, output from this module is connected to B1,B2 terminals of Slide switch.

C1, C2 terminals are connected to the Lithium Ion battery (always mind the polarity +Ve, -Ve), MT3608 DC-DC Boost module directly connected to the Li-Ion Battery terminals and you can add ON/OFF switch to control the output. This MT3608 module gives step up DC voltage upto 26V and the output voltage can be varied by the trimpot. By using DPDT slide switch we can choose the input power source to charge the battery.

DPDT Slide Switch


  • Do not short circuit any parts.
  • Be more caution to handle Lithium Ion battery.
  • This design includes high voltage input handle with extreme care.

2 thoughts on “Portable Power Supply Unit

  1. Bad Idea to connect the LI-ION Battery directly to the AC-Powersupply. The “Charge Current and Volatge” is not controlled by an LI-ION Charger Circuit. Better connecting the LI-ION Battery ONLY to the Charger and the Boost Converter switching between AC and LI-ION Battery.

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