This is a very small 1S lithium battery charger board designed for projects where space is extremely limited. It charges single-cell Li-ion or Li-Po batteries (3.7V nominal) using a USB Type-C input. You just plug in a Type-C cable, connect a 1S battery, and the board safely handles the charging process.

How to Use This Charger

• Connect Power

1. Plug a USB Type-C cable into the board.
2. It accepts 5V from any phone charger, power bank, or laptop.

• Connect the Battery

1. Connect the battery B+ to the positive terminal.
2. Connect GND to the battery negative terminal.

• Charging Status

1. Red LED ON → Battery is charging
2. Green LED ON → Battery is fully charged / standby

What This Board Does

This ultra-compact board is designed to safely charge single-cell (1S) Li-ion and Li-Po batteries using a standard 5V USB Type-C power source. It follows the correct constant-current / constant-voltage (CC/CV) charging method, which is essential for maintaining battery health and long-term reliability. Once the battery reaches full charge, the board automatically stops charging, preventing overcharging and improving safety. Despite its extremely small size, the charger remains fully compatible with modern USB Type-C chargers, including phone adapters, power banks, and laptops.

Where You Can Use It

Because of its tiny footprint, this charger is ideal for projects where space is a critical constraint. It fits perfectly into wearable electronics, IoT and sensor-based devices, and small robotic systems. It is also well suited for smart badges, DIY gadgets, and custom battery-powered PCBs, especially in designs where commonly available TP4056 charging modules are simply too large. This makes the board a practical solution for both hobbyist projects and compact product prototypes.

Why This Design Is Special

What makes this design stand out is its extreme level of miniaturization without sacrificing functionality. The board uses 0201-sized components to achieve one of the smallest possible charger layouts. A USB Type-C connector replaces older Micro-USB designs, making the board more future-proof and convenient to use. The schematic is kept clean and minimal, reducing complexity while improving reliability. As a result, the charger is easy to integrate into any project, even when board space is extremely limited.

Summary

This project demonstrates how a complete and safe lithium battery charger can be designed in an ultra-compact size. Simply connect a USB Type-C power source and a 1S battery, and the board handles everything automatically. It is an ideal solution for modern electronics projects where space is limited.