34673

Freescale Semiconductor Advance Information Document Number: MC34673 Rev. 1.0, 01/2008 High Input Voltage 1.2A Charger for Single-cell Li-Ion Batteries 34673 The MC34673 is a cost-effective fully-integrated battery charger for Li-Ion or Li-Polymer batteries. The high input voltage, up to 28V, eliminates the input over-voltage protection circuit required in handheld devices such as PDAs, cell phones, portable video game players and digital still cameras. A typical charge cycle includes trickle, constant-current (CC) and constant-voltage (CV) charge modes. The CC-mode current is programmable up to 1.2A with an external resistor. The voltage across the external resistor is also used to monitor the actual charge current. The constant voltage is fixed at 4.2V with 0.7% accuracy over a -20°C to 70°C temperature range. The trickle-mode current is preset to 20% of the CC-mode current when the battery voltage is lower than the trickle-mode threshold. The end-of-charge (EOC) current threshold is preset to 10% of the CC-mode current to save the 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 MC34673 also protects the system with its input over-voltage protection (OVP) feature. In addition, the MC34673 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 interfac...