Battery Back-Up System Manager from Linear Technology

The LTC4110 can provide a supply voltage to a system load from a main supply or battery and can also charge a battery, thereby providing an uninterruptible power source for the system. The IC is capable of supplying voltages above or below the input supply rail, allowing the designer to optimize the battery configuration independent of input supply considerations. When the main supply is present, the LTC4110's PowerPath™ control feature provides power to the system load and, if needed, preferentially and simultaneously charges the battery. If the main supply fails, the LTC4110 uses the battery as a power source through low loss switches to continue providing a supply voltage to power the system. The low loss battery calibration mode discharges the battery (through a high efficiency flyback converter) into the system load, thus eliminating wasted heat and energy. Shutdown mode disconnects the battery from the load to preserve capacity. In addition it offers the ability to ship the end product with a fully charged battery with minimal drainage.

The LTC4110 supports multiple battery chemistries: Li-Ion/Polymer, Nickel and lead acid, and is compatible with supercapacitors. Multiple LTC4110s can be combined to form a redundant battery backup system or increase the number of battery packs to achieve longer backup run times. The IC provides support for both standard and Smart Battery packs. If the optional SMBus/I2C interface is used, the host may access internal status, control the 3 GPIO pins as desired, and support battery capacity and gas gauge calibration to verify the battery's ability to support the load. The GPIO pins can also be configured as status outputs on power up.

Other features of the LTC4110 include programmable charge/calibration current up to 3A with ±3% accuracy, wide backup battery supply range of 2.7V to 19V, wide input supply range of 4.5V to 19V, over- and under-battery voltage protection, adjustable battery float voltage with precision charge voltage of ±0.5%, and optional temperature-qualified charging with a thermistor input. A no-heat calibration state is provided to assure the battery is maintaining charge. During this calibration state, the energy from the battery is sourced to the load rather than being dissipated as heat.

The LTC4110 is housed in a low-profile (0.75mm) 38-pin 5mm x 7mm QFN package and is guaranteed for operation from -40°C to 85°C.