SMB138 Datasheet, PDF (1/2 Pages) Summit Microelectronics, Inc. – Programmable Switch-mode, USB/AC Input Li+ Battery Charger with TurboCharge

SMB138/A/C
Programmable Switch-mode, USB/AC Input Li+ Battery Charger with TurboCharge™ Mode
and USB “On- the-Go” Power
FEATURES & APPLICATIONS
INTRODUCTION
• USB or AC input with programmable input current limiting
• Up to 1.25A continuous charging current from AC adapter
• Up to 750mA charging current from 500mA USB port using
The SMB138 is a programmable single-cell lithium-ion/lithium-polymer
battery charger designed for a variety of portable applications. The
device provides a simple and efficient way to charge high-capacity Li-
Ion batteries via a USB or AC adapter input. Unlike conventional
automatic TurboCharge™ mode
devices, the SMB138’s high-efficiency, switch-mode operation
• +4.35 to +6.2V input voltage range (+16V tolerant)
eliminates the thermal problems of conventional linear solutions. Also
• Two product options:
o SMB138A: charger off until I²C command initiation,
enable/disable control via I²C
the buck converter architecture effectively multiplies the input current
to increase charge rate for the Li+ cell and uses current limited
supplies like USB more efficiently. The SMB138 also supports USB
o SMB138C: charger powers up in charging mode,
enable/disable control via I²C
On-the-Go devices by providing the required USB-OTG +5V power
supply using the Li-Ion battery as a source.
• USB “On-the-Go” Power support for USB OTG enabled
devices (+5V reverse output @ 200mA)
• Reverse current blocking (<5uA)
• High-efficiency 3MHz voltage-mode step-down regulator
The SMB138 can switch between USB mode and AC Adapter mode
and works seamlessly in conjunction with a USB controller. Charge
control includes qualification, trickle-charge, pre-charge, constant
current/constant voltage, float voltage and termination/safety settings
• Integrated frequency compensation
that are fully programmable via a serial I²C/SMBus and stored in non-
• Internal power MOSFETs and precision current sensing
volatile memory making the device truly a flexible solution. Fast
•
•
•
•
CONFIDENTIAL ^{High-accuracy float voltage regulation: 1%}
Thermal regulation (current foldback)
Trickle charging
Pre-charge and complete-charge (36/240min) safety timers
charge current level can be set via I²C (limited in USB mode to ensure
100mA or 500mA input). Built-in is reverse-current blocking to prevent
inadvertent cell discharge. High frequency operation and integrated
power FETs contribute to reduced external component count and size.
• Digital programming of all major parameters via I²C interface
The SMB138A device requires a user I²C command for charging
o Fast charge voltage threshold, float voltage
initiation, whereas the SMB138C device powers up in the charging
•
•
DO NOT COPY ^{o Pre-charge, fast charge, termination current}
Status register monitors and flags charger operation
o Charge in-progress/termination
o Charge timer fault
o OC/UV/OV detection/shutdown
uCSP-19 lead-free package (0.4mm ball pitch)
mode. The SMB138C offers the option to automatically charge the
battery only when the battery voltage is below a selectable “dead-
battery” threshold.
The SMB138 also offers several features that protect the battery pack
as well as the charger and input circuitry: over-current, under/over-
voltage and thermal protection. Ultra-accurate, 1% battery float
voltage control improves battery capacity utilization. The STAT output
Applications
• 2.5/3/3G+ GSM/CDMA/WCDMA Phones
• Smartphones/PDAs
• Portable Media Players
is an interrupt to flag various status/flag events (programmable
selection) and the status register can be read via the serial port. The
SMB138 is available in an ultra-compact lead-free uCSP-19 package
and is rated over the –30C to +85C temperature range.
• Portable GPS Terminals
SYSTEM APPLICATION
USB
500mA
4.35V-5.5V
Handheld System
USB-OTG Output
500mA
Total Output
550-1250mA
To system
USB
SMB138
System
Li-Ion
USB
I2C
USB
AC/DC
300-1800mA
4.5V-6.2V
Figure 1 – Using the SMB138 to charge a single cell Li+ battery from USB or AC Adapter power sources
© SUMMIT Microelectronics, Inc. 2004 • 757 N. Mary Avenue • Sunnyvale CA 94085 • Phone [phone] • FAX [phone]
http://www.summitmicro.com/
3.0 4/5/2008
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