SparkFun LiPo Charger Plus

The SparkFun LiPo Charger Plus is a high-powered single-cell lithium polymer (LiPo) battery charger. This model features a USB-C input charge connector along with an option for charge rate selection and thermal protection. The board is compatible with any 2-pin JST connector single cell LiPo batteries in the SparkFun range. Charging progress is indicated by charge, power, and done LEDs.

The MCP73833, which operates at an input voltage between 3.75V-6V, can charge at a maximum rate of 1000mAh. It offers two types of thermal protection. An internal sensor ensures the maximum charging rate until the die temperature of the IC reaches approximately 95°C. The charge controller then reduces the charge rate to prevent overheating. The MCP73833 also comes with an optional input pin for an NTC (negative-temperature coefficient) thermistor, providing an additional layer of protection against possible battery damage.

The SparkFun LiPo Charger Plus has a host of features that make it a reliable and efficient battery charging solution. It is a complete linear charge management controller with an integrated pass transistor, current sense, and reverse discharge protection. It operates on constant current/constant voltage with thermal regulation. The charge current is programmable up to a maximum of 1A. The preset voltage regulation is highly accurate at 4.2V + 0.75%. The charger also has the ability to precondition deeply depleted cells with selectable current ratio and voltage threshold. It includes a cell temperature monitor and a low-dropout linear regulator mode. The supply voltage ranges from 3.75V-6V.

For users who are interested in understanding the inner workings of the SparkFun LiPo Charger Plus, a schematic, eagle files, a hookup guide, a Fritzing part, a datasheet for the MCP73833, and a GitHub hardware repo are available.