I designed this power supply for small projects, prototyping, Arduino, IoT, and wireless embedded applications. An ATtiny45 provides the ideal balance between features and efficiency. When on, efficiencies go as high as 92%. When off, it consumes just 2μA! It uses two LEDs, red and green, to provide simple information about the charging and power of the device.
This power supply has protection for input overcurrent, output short circuit, output disconnect, battery disconnect, battery overvoltage, and battery undervoltage.
It's difficult to find a power supply to convert a Lithium-Ion battery to a 1.8V, 3.3V, or 5V with high current output, high efficiency, and safety features. This board uses the Texas Instruments TPS63020, which is capable of this task.
This power supply uses a single cell Lithium-Ion battery. The battery is charged at a maximum of 500mA using the Microchip MCP73831. A battery is required to use this power supply.
4A peak output (100ms max)
2A continuous output
2μA sleep current
Micro USB charge input
Micro JST Connector for Single Cell Li-Ion
500mA max charge rate
Minimum recommended battery capacity - 500mAh
Green and Slow Blinking Red
ON, battery low (<30%)
Green and Fast Blinking Red
ON, battery critical (<10%)
OFF, fully charged
Efficiency (LEDs off, Vbat = 3.6V)
This project is Open Source and Open Hardware under the CC BY-SA license