Power Bank Circuit Diagram

The Power Bank Circuit Diagram project demonstrates how to build a portable power supply by integrating a lithium-ion battery charging circuit with a step-up voltage converter. At the heart of the input stage is the TP4056 IC module, which manages the safe charging of the 3.7V 2600mAh Samsung 18650 rechargeable lithium-ion battery from a standard USB power source. The TP4056 handles constant-current and constant-voltage charging profiles essential for safe lithium chemistry. Connected in parallel with the battery circuit is an on-and-off switch (S1) alongside configuration resistors, which govern the power state and control signal paths. When the switch is closed, power flows from the 3.7V battery into a DC-DC boost converter module utilizing PFM (Pulse Frequency Modulation) technology. Because a standard single-cell lithium-ion battery outputs a nominal voltage that fluctuates between 3.0V and 4.2V, it is insufficient to directly power devices requiring a standard 5V USB input. The PFM boost converter dynamically steps up this lower battery voltage to a stable 5V output capable of driving external electronics. Together, these discrete modules and components bridge the gap between low-voltage energy storage and practical USB mobile device charging.