The RT9531 is a PWM switch mode battery charger controller to fast charge single or multiple Li-Ion, NiMH and NiCd batteries, using constant current or constant voltage control. Maximum current can be easily adjusted by external resistor. The constant voltage output can support up to 4 Li-Ion cells with 0.5% accuracy.
A third control loop limits the input current drawing from the adapter during charging. This allows simultaneous operation of the equipment and fast battery charging without over loading to the adapter.
The RT9531 can charge batteries from 2.5V to 4.2V with dropout voltage as low as 0.4V. A diode is not required in series with the battery because the charger automatically enters a 10μA sleep mode when the adapter is unplugged. A logic output indicates Li-Ion full charge when current drops to 20% of the full-scale adjusted charge current.
Applications
- Notebook Computers
- Portable Instruments
- Chargers for Li-Ion, NiMH, NiCd and Lead Acid Rechargeable Batteries