RT9511 Datasheet, PDF (1/24 Pages) Richtek Technology Corporation – Fully Integrated Battery Charger with Two Step-Down Converters

RT9511
Fully Integrated Battery Charger with Two
Step-Down Converters
General Description
The RT9511 is a fully integrated low cost solution with a
single-cell Li-Ion battery charger and two high efficiency
step-down DC/DC converters ideal for portable
applications.
The Battery Charger is capable of being powered up from
AC adapter and USB (Universal Serial Bus) port inputs
which can automatically detect and select the AC adapter
and the USB port as the power source for the charger.
The Battery Charger enters sleep mode when both
supplies are removed. The Battery Charger optimizes the
charging task by using a control algorithm including
preconditioning mode, fast charge mode and constant
voltage mode. The charging task is terminated as the
charge current drops below the preset threshold. The USB
charge current can be selected from preset ratings100mA
and 500mA, while the AC adapter charge current can be
programmed up to 1A with an external resister. The internal
thermal feedback circuitry regulates the die temperature
to optimize the charge rate for all ambient temperatures.
The Battery Charger features 18V and 7V maximum rating
voltages for AC adapter and USB port inputs respectively.
The other features are external programmed safety timer,
under voltage protection, over voltage protection for AC
adapter supply, battery temperature monitoring and charge
status indicator.
The high-efficiency step-down DC/DC converter is capable
of delivering 1A output current over a wide input voltage
range from 2.5V to 5.5V, the step-down DC/DC converter
is ideally suited for portable electronic devices that are
powered from 1-cell Li-ion battery or from other power
sources such as cellular phones, PDAs and hand-held
devices. Two operating modes are available including :
PWM/Low-Dropout autoswitch and shut-down modes. The
Internal synchronous rectifier with low R_DS(ON) dramatically
reduces conduction loss at PWM mode. No external
Schottky diode is required in practical application.
The RT9511 is available in a WQFN -24L 4x4 package.
Features
z Battery Charger
` Automatic Input Supplies Selection
` 18V Maximum Rating for AC Adapter
` Integrated Selectable 100mA and 500mA USB
Charge Current
` Internal Integrated Power FETs
` Charge Status Indicator
` External Capacitor Programmable Safety Timer
` Under Voltage Protection
` Over Voltage Protection
` Automatic Recharge Feature
` Battery Temperature Monitoring
` Thermal Feedback Optimizing Charge Rate
` Power Path Controller
z Step-Down DC/DC Converter
` Adjustable Output from 0.6V to VIN
` 1A Output Current
` 95% Efficiency
` No Schottky Diode Required
` 1.5MHz Fixed-Frequency PWM Operation
z Small 24-Lead WQFN Package
z RoHS Compliant and Halogen Free
Applications
z MP3/MP4 Player
z GPS
z Digital Photo Frame
z Hand held Device
Marking Information
For marking information, contact our sales representative
directly or through a Richtek distributor located in your
area.
DS9511-01 April 2011
www.richtek.com
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