TP4054

The TP4054 is a complete constant-current/constant-voltage linear charger IC for single-cell lithium-ion batteries. Its SOT package and minimal external components make it ideal for portable applications, compatible with both USB power supplies and adapter power sources. The internal PMOSFET architecture with reverse-charge protection eliminates the need for external sense resistors and isolation diodes. Thermal feedback regulates the charge current to limit the die temperature. The charge voltage is fixed at 4.2V, while the charge current is externally programmable via a resistor. Charging terminates automatically when the charge current drops to 1/10 of the programmed value after the final float voltage is reached. When the input voltage is removed, the device automatically enters a low-current state, reducing battery leakage current to below 3uA; a shutdown mode is also available to reduce supply current to 45uA. Additional features include a charge current monitor, undervoltage lockout, automatic recharge, and a status pin.

Applications

• Small fans
• Electric toothbrushes
• USB appliances
• Charging docks
• Power tools

Key features

• Programmable charge current up to 500mA
• No MOSFET, sense resistor, or blocking diode required
• Thermal regulation with constant-current/constant-voltage operation maximizes charge rate without risk of overheating
• Charges single-cell Li-Ion batteries directly from USB port
• 4.2V preset charge voltage with ±1% (±42mV) accuracy
• 2.9V trickle charge threshold with 0V battery charging support
• 75μA supply current in standby mode
• Integrated charge status output simplifies peripheral circuitry
• 5-pin SOT-23 package