Evaluation Board For MC34671

The Evaluation Kit features the MC34671, which is a cost-effective fully integrated battery charger for Li-Ion or Li-Polymer batteries. It tolerates an input voltage up to 28V, 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 600mA, with an external resistor.The constant voltage is fixed at 4.2V. 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 2.6V 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 1.0µA leakage current from the battery.

No external MOSFET, reverse-blocking diode, or current-sense resistor are required

Guaranteed maximum 600mA programmable charge current

±0.7% voltage accuracy over -20°C to 70°C

±5% current accuracy over -40°C to 85°C

28V maximum voltage for the power input with 11V over-voltage protection threshold

2.6V minimum input operating voltage

Trickle charge for fully discharged batteries

Charge current monitor

Charge current thermal foldback