ISL9201
Li-ion Battery Charger

Key Features

• Complete Charger for Single-Cell Li-ion/Polymer Batteries
• Integrated Pass Element and Current Sensor
• No External Blocking Diode Required
• Low Component Count and Cost
• 25mV Voltage Accuracy Over-Temperature and Input Voltage Range
• 20mV Voltage Accuracy at Room Temperature
• Programmable Charge Current
• Charge Current Thermal Foldback for Thermal Protection (Thermaguard®)
• Trickle Charge for Fully Discharged Batteries
• Power Presence and Charge/EOC Indications
• Less than 4µA Leakage Current off the Battery when No Input Power Attached or Charger Disabled
• Ambient Temperature Range: -40°C to +85°C
• DFN Package
• Pb-Free Plus Anneal Available (RoHS Compliant)

Description

The ISL9201 is an integrated single-cell Li-ion or Li-polymer charger capable of operating at an input voltage as low as 2.5V. The low operating voltage allows the charger to work with a variety of AC adapters.

The ISL9201 operates as a linear charger when the AC adapter is a voltage source. The battery is charged in a standard Li-ion charge profile, i.e. a constant current phase followed be a constant voltage phase (CC/CV). The charge current during the constant current phase is determined by the external resistor connected to the IREF pin. When the adapter output is a current-limited voltage source and the current limit is smaller than the programmed constant current of the IC, the ISL9201 operates as a pulse charger where the charge current is determined by the current limit of the AC adapter during the constant current phase. The ISL9201 operates in a linear mode during the constant voltage phase in both adapter cases.

The ISL9201 incorporates Thermaguard®, which protects the IC against over-temperature. If the die temperature rises above a typical value of +110 °C, the thermal foldback function reduces the charge current to prevent further temperature rise. The ISL9201 also includes a timer to set the time reference for the delay time of the end-of-charge (EOC) and recharge indications. The timer is programmable with an external capacitor. A logic input and an open-drain logic output are available for controlling the charger and indicating the charger status. The EN pin enables the charger. The STATUS pin is an open-drain output which turns on when the charger is delivering current. The charger uses a 10 Ld 3x3 DFN package to maximize thermal conductivity.

Applications

• Mobile Phones
• Blue-Tooth Devices
• PDAs
• MP3 Players
• Stand-Alone Cradle or Travel Chargers
• Other Handheld Devices