LM3647

The LM3647 is a charge controller for Lithium-Ion (Li-Ion), Nickel-Metal Hydride (Ni-MH) and Nickel-Cadmium (Ni- Cd) batteries. The device can use either a pulsed-current charging or a constant-current charging technique. The device can also be configured to discharge before charging. Throughout the charging sequence the LM3647 monitors voltage and/or temperature and time in order to terminate charging.

 Negative delta voltage (-DV)
Maximum voltage
Optional: Delta temperature/delta time (DT/Dt)
Optional: Maximum temperature
Backup: Maximum time
If both voltage and temperature fail to trigger the termination requirements, then the maximum time (configured by external hardware) steps in which terminates the charging. In Ni-Cd/Ni-MH mode, four different charging stages are used:
Soft-start charge
Fast charge
Topping charge
Maintenance charge
In Li-Ion mode, four different charging stages are used:
Qualification
Fast Charge Phase 1, Constant Current
Fast Charge phase 2, Constant Voltage
 Maintenance charge
The charge current of the LM3647 is configured via external resistors, which in turn controls the duty cycle of the PWM switching control output. For cost-sensitive applications, the LM3647 charge controller can be configured without a temperature sensor and to use an external current source.