CCCV Battery Charger

CCCV Battery Charger schematic

This is a very simple CCCV (Constant current - Constant voltage) charger for Li-Ion batteries.  At battery voltages below the U2 regulator set point, the circuit will supply a constant current from U1 as set by the value of R2.  When the battery voltage is equal to the U2 set point the current will decay as the internal (ESR ignored) cell voltage rises until the charging current eventually reaches zero.  When the charger switches to constant voltage operation, the battery is typically at 80% capacity and when the current decays to less than 20mA the battery can be considered fully charged.  See Fig-4a of the Analog Devices app note for a typical charging cycle curve.

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This page last updated on December 02, 2009