Cost and design complexity in Li-ion and Li-polymer systems can be reduced by using the new programmable battery-charger ICs from Summit Microelectronics, the company believes. The SMB239 is claimed to be the industry's smallest charger IC, enabling slimmer industrial designs for portable consumer electronics. The device's battery-charging parameters are programmable via the I2C interface and non-volatile memory, allowing system design without any hardware changes. A 500mA linear charger uses a programmable algorithm for single-cell Li-ion and Li-polymer batteries. All charging parameters—pre-charge, fast charge, charge-termination current, cell float, pre-charge voltage, battery temperature and timer safety limits—are configurable via the I2C/SMBus interface. Default or custom configuration in non-volatile memory allows the same product to be used in different system designs and/or with different battery types and technologies. Host-software-control capability allows in-system adjustment of the charging profile, minimising charging time and enhancing safety. The IC is offered in a small 2.1x1.3mm chip-scale package and requires just two small external chip capacitors to create a complete battery-charging-system design. The device also eliminates the need for multiple external components which, in other models, are necessary for setting charging parameters. Safety features include input and battery overvoltage protection and blocking up to +10V, current limit, chip and battery thermal protection, safety timers and battery-missing detection. Operating-input range is 4.35 to 6.5V, and reverse leakage current is less than 2µA.
