Multiple-cell battery stacks can be charged and balanced by configuring several LTC4070s in series. Housed in a low profile (0.75mm) 8-lead 2mm x 3mm DFN package, the LTC4070 provides a complete and ultra-compact charger solution with only a single external resistor required in series with the input voltage. The device’s feature set is well suited for continuous and intermittent, lower power charging source applications, including Lithium-Ion/Polymer battery backup, thin film batteries, coin cell batteries, memory backup, solar-powered systems with backup, embedded automotive and energy scavenging/harvesting.
With pin-selectable settings of 4.0V, 4.1V, or 4.2V, the LTC4070’s 1% accurate battery float voltage allows the user to optimize the balance between battery capacity and lifetime. Independent low battery and high battery supervisory status outputs indicate a discharged or fully charged battery. In conjunction with an external PFET in series with the load, the low battery status output enables a latch-off function that automatically disconnects the system load from the battery to protect the battery from deep discharge.