Microchip announced the MCP73833 and MCP73834 single-cell Li-Ion/Li-Polymer linear charge-management controllers. Because they combine a pass transistor, current-sense and reverse-discharge protection on a single chip, the devices eliminate the need for external components. Multiple combinations of key charging parameters, including pre-conditioning current threshold and ratio, charge-termination threshold and recharge threshold ratio are available, meaning the devices provide standard product support for a variety of high-current Li-Ion/Li-Polymer battery charger applications. Additionally, with high charging currents of up to 1A and support for multiple regulated output voltages (4.2V, 4.35V, 4.4V and 4.5V), the devices can be used with early generation batteries where output voltages are lower, as well as newer batteries where output voltages are higher. Safety features onboard the MCP73833/4 include charge timers, battery-temperature feedback and thermal-current regulation. The charge timer shuts the charger off if a charge is not terminated before timeout is reached. The battery-temperature feedback reduces the charge current when the battery's temperature exceeds safe levels.

The thermal-current regulation feature decreases the charge current when the device reaches its thermal limits. All of these safety features keep the battery from overcharging and overheating. Device-specific features include a power-good output on the MCP73833 and a timer-enable input on the MCP73834. The timer-enable input can disable the timer when the battery is charged at the same time that current is supplied to the system. Both devices offer a low dropout regulator (LDO) test mode that enables application system test even in the absence of a battery; and both feature two status outputs to provide the user with additional information about the battery chargers state. These features help to prevent battery-related system damage, resulting in safer, more efficient and more reliable charger designs.

Support and Pricing

To support development using the MCP73833/4 charge-management controllers, Microchip offers the MCP73833 Li-Ion Battery Charger Evaluation Board. The board is priced at $20. The MCP73833/4 charge-management controllers are available in 10-pin MSOP and DFN (3 mm x 3 mm) packages. The devices are priced at $.87 each in 10,000-unit quantities for all devices and package options.