Power
Tiny Sub-1µA IQ Shunt Battery System Charges & Protects Li-Ion/Polymer Batteries
Linear Technology introduced the LTC4070, an easy-to-use, tiny shunt battery charger system IC for Li-Ion/Polymer batteries. The LTC4070, with its 450nA operating current, charges and protects batteries from previously unusable very low current, intermittent or continuous charging sources. The LTC4070's charge current may be boosted from 50mA up to 500mA with the addition of an external PMOS shunt device. An internal thermal battery conditioner reduces the float voltage to protect Li-Ion/Polymer cells at elevated battery temperatures.
MultWith 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.