特点
Charges Single-Cell Li-Ion Battery from Wall Adapter and USB Inputs
Automatic Input Power Detection and Selection
Charge Current Programmable Up to 950mA from Wall Adapter Input
Adjustable Output, High Ef?ciency 600mA Synchronous DC/DC Converter
No External MOSFET, Sense Resistor or Blocking Diode Needed
Thermal Regulation Maximizes Charge Rate Without Risk of Overheating
Preset Charge Voltage with ±0.6% Accuracy
Programmable Charge Current Termination
1.5MHz Constant Frequency Operation (Step-Down Converter)
18μA USB Suspend Current in Shutdown
“Power Present” Status Output
Charge Status Output
Automatic Recharge
Available in a Thermally Enhanced, Low Pro?le (0.75mm) 16-Lead (5mm × 3mm) DFN Package
典型应用
典型应用
描述
Internal thermal feedback regulates the battery charge current to maintain a constant die temperature during high power operation or high ambient temperature conditions. The ?oat voltage is ?xed at 4.2V and the charge currents are programmed with external resistors. The LTC3550 terminates the charge cycle when the charge current drops below the programmed termination threshold after the ?nal ?oat voltage is reached. With power applied to both inputs, the LTC3550 can be put into shutdown mode reducing the DCIN supply current to 20μA, the USBIN supply current to 10μA, and the battery drain current to less than 2μA.
The DC/DC converter switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors.