LM3622 Lithium-Ion Battery Charger Controller
February 2000
LM3622 Lithium-Ion Battery Charger Controller
General Desc...
LM3622 Lithium-Ion Battery Charger Controller
February 2000
LM3622 Lithium-Ion Battery Charger Controller
General Description
The LM3622 is a charge controller for Lithium-Ion batteries. This monolithic integrated circuit accurately controls an external pass transistor for precision Lithium-Ion battery charging. The LM3622 provides a constant
voltage or constant current (CVCC) configuration that changes, as necessary, to optimally charge lithium-ion battery cells.
Voltage charging versions (4.1V, 4.2V, 8.2V, and 8.4V) are available for one or two cell battery packs and for coke or graphite anode battery chemistry. The LM3622 accepts input
voltages from 4.5V to 24V. Controller accuracy over temperature is ± 30mV/cell for A grade and ± 50mV/cell for the standard grade. No precision external resistors are required. Furthermore, the LM3622’s proprietary output
voltage sensing circuit drains less than 200nA from the battery when the input source is disconnected. The LM3622 circuitry includes functions for regulating the charge
voltage with a temperature compensated bandgap reference and regulating the current with an external sense resistor. The internal bandgap insures excellent controller performance over the operating temperature and input supply range. The LM3622 can sink 15mA minimum at the EXT pin to drive the base of an external PNP pass transistor. It also has low-
voltage battery threshold circuitry that removes this drive when the cell
voltage drops below a preset limit...