FAN54005: USB-Compliant Single-Cell Li-Ion Switching Charger with USB-OTG Boost Regulator

The FAN54005 combines a highly integrated switch-mode charger, to minimize single-cell Lithium-ion (Li-ion) charging time from a USB power source, and a boost regulator to power a USB peripheral from the battery.

The charging parameters and operating modes are programmable through an I2C Interface that operates up to 3.4 Mbps. The charger and boost regulator circuits switch at 3 MHz to minimize the size of external passive components.

The FAN54005 provides battery charging in three phases: conditioning, constant current and constant voltage.

To ensure USB compliance and minimize charging time, the input current limit can be changed through the I2C interface by the host processor. Charge termination is determined by a programmable minimum current level. A safety timer with reset control provides a safety backup for the I2C host. Charge status is reported to the host through the I2C port.

The integrated circuit (IC) automatically restarts the charge cycle when the battery falls below an internal threshold. If the input source is removed, the IC enters a high-impedance mode, preventing leakage from the battery to the input. Charge current is reduced when the die temperature reaches 120°C, protecting the device and PCB from damage.

The FAN54005 can operate as a boost regulator on command from the system. The boost regulator includes a soft-start that limits inrush current from the battery and uses the same external components used for charging the battery.

Features

• Fully Integrated, High-Efficiency Charger for Single-Cell Li-Ion and Li-Polymer Battery Packs
• Charge Voltage Accuracy:
  • ±0.5% at 25°C
  • ±1% from 0 to 125°C
• ±0.5% at 25°C
• ±1% from 0 to 125°C
• ±5% Input Current Regulation Accuracy
• ±5% Charge Current Regulation Accuracy
• 20 V Absolute Maximum Input Voltage
• 6 V Maximum Input Operating Voltage
• 1.45 A Maximum Charge Rate
• Programmable through High-Speed I2C Interface (3.4 Mb/s) with Fast Mode Plus Compatibility
  • Input Current
  • Fast-Charge / Termination Current
  • Charger Voltage
  • Termination Enable
• Input Current
• Fast-Charge / Termination Current
• Charger Voltage
• Termination Enable
• 3 MHz Synchronous Buck PWM Controller with Wide Duty Cycle Range
• Small Footprint 1 H External Inductor
• Safety Timer with Reset Control
• 1.8 V Regulated Output from VBUS for Auxiliary Circuits
• Dynamic Input Voltage Control Automatically Reduces Charging Current with Weak Input Sources
• Low Reverse Leakage to Prevent Battery Drain to VBUS
• 5 V, 500 mA Boost Mode for USB OTG for 3.0 V to 4.5 V Battery Input
• Available in a 1.96 x 1.87 mm, 20-bump, 0.4 mm Pitch WLCSP Package