Circuit Lake

Electronic Project and Circuit Collection

Single Li-Ion / Li-Polymer Battery Charger

01/23/2013 Category: Analog, Basic

The MCP73837 and MCP73838 based charger is suitable for portable applications. It is fully integrated linear Li-Ion / Li-Polymer battery chargers with autonomous power source selection. It has small physical size and only need low number of external components to make it works. The MCP73837 support Power-Good Monitor while MCP73838 has Timer Enable feature.

MCP73837-based Battery Charger
Click for larger image
MCP73837-based Battery Charger

The MCP73837/8 automatically selects the USB-port or AC-adapter as the power source for the system. For the USB-port powered systems, the MCP73837/8 specifically adheres to the current limits governed by the USB specification. The host microcontroller can select from two preset maximum charge current rates of 100 mA (low power USB-port) or 500 mA (high power USB-port). With an AC-adapter providing power to the system, an external resistor sets the magnitude of the system or charge current up to a maximum of 1A.

MCP73838-based Battery Charger
Click for larger image
MCP73838-based Battery Charger

The MCP73837/8 employs a constant current/constant voltage charge algorithm with selectable preconditioning and charge termination. The constant voltage regulation is fixed with four available options: 4.20V, 4.35V, 4.40V, or 4.50V, to accommodate the new emerging battery charging requirements. The MCP73837/8 limits the charge current, based on die temperature, during high power or high ambient conditions. This thermal regulation optimizes the charge cycle time while maintaining the device reliability. Download MCP73837 and MCP73838 datasheet.