The MC34671 is a cost-effective fully integrated battery charger for Li-Ion or Li-Polymer batteries. It tolerates an input voltage up to 28 V, which eliminates the input over-voltage protection circuit required in handheld devices. A charge cycle includes trickle, constant-current (CC) and constant-voltage (CV) charge modes.
The constant-current (CC) is programmable up to 600 mA, with an external resistor.The constant voltage is fixed at 4.2 V. The trickle charge current is preset to 20% of the CC current when the battery voltage is lower than the trickle-charge threshold. The end-of-charge (EOC) current threshold is preset to 10% of the CC current to save board space and cost. A charge-current thermal foldback feature limits the charge current when the IC internal temperature rises to a preset threshold.
The MC34671 has a 2.6 V falling power-on-reset (POR) threshold, making it perfect to work with current-limited power supplies. Three indication pins (PPR, CHG, and FAST) can be simply interfaced to a microprocessor or LEDs. When no power supply is connected, or when disabled, the charger draws less than 1.0 µA leakage current from the battery.