Battery charger features multi-chemistry operation

A resistor-programmable 1.2V to 60V battery charge voltage range with tight ±0.5% charge voltage accuracy and onboard charge termination makes the LTC4079 suitable for many battery chemistries, including Li-Ion, nickel and lead acid. The charge current is adjustable from 10mA to 250mA with an external resistor, and unlike competing chargers, the device maintains high accuracy at low charge currents.

The charger’s input voltage regulation function can regulate the IN pin to a constant voltage or to a constant differential voltage above the battery, when charging from a current-limited power source such as a weak battery or solar panel. These features can be used to prevent the input voltage from collapsing below the undervoltage lockout (UVLO) voltage, or to maintain the input source voltage at its peak power transfer point.

The charge current is reduced as the input voltage falls below the programmed threshold. This regulation mechanism allows the charge current to be selected based on the battery requirement and the maximum available power from the charging input source, while letting the LTC4079 take care of situations when the input source cannot provide the full programmed charge current.

The device’s thermal regulation feature ensures maximum charge current up to the specified limit without the risk of overheating. Charging can be terminated via C/10 or an onboard adjustable timer. Other features include NTC thermistor temperature-qualified charging, bad battery detection, automatic recharge with sampled feedback in standby for negligible battery drain and an open-drain CHRG pin status output.

The charger is housed in a low profile (0.75mm) 10-pin 3mm x 3mm DFN package with backside metal pad for excellent thermal performance. It is guaranteed for operation from -40°C to 125°C, in both E-and I-grades.