SMB137B Preliminary Information Programmable Switching Li+ Battery Charger with USB/AC Input, CurrentPath™ Manager, TurboChargeTM Mode*, Low Battery Recovery*, AICL* and USB On-The-Go Support FEATURES & APPLICATIONS INTRODUCTION • Automatic Input Current Limit for universal USB/AC/DC adapter compatibility* • Optional automatic power source detection per latest USB charging specification 1.0 • USB or AC input with automatic input selection and programmable input current limiting (USB2.0 compliant) • Up to 750mA charging output from 500mA USB port or 1500mA TM from AC adapter using proprietary “TurboCharge Mode” • Input/output CurrentPath™ control allows system operation with deeply discharged/missing battery – no start-up delay • “Low Battery Recovery” mode for >500mA startup from 100mA USB port with deeply discharged cells – no start-up delay • USB On-the-Go (OTG) power support (up to 500mA @ +5V) • Reverse current blocking prevents battery discharge • High-efficiency step-down regulator with 3MHz switching • +4.35 to +6.0V input voltage range • +18V input tolerance (non-operating) • High-accuracy float voltage regulation: 1.0% 2 • Digital programming of all major parameters via I C interface o Pre-charge voltage, float voltage o Input/pre-charge/fast charge/term. current o Battery temperature limits, safety timers • Comprehensive protection features o Status/fault indicator o Battery/IC thermal protection o Short circuit/UV/OV protection o Charge termination safety timers o Software watchdog timers • Tiny CSP-30 package The SMB137B is a programmable single-cell lithium-ion/lithiumpolymer 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 charging devices, the SMB137B’s high-efficiency switch-mode operation eliminates the low charge current and thermal problems of conventional linear solutions. In addition, the switching architecture in conjunction with programmability enables dramatically faster charging – TurboCharge™ mode - from current limited in puts such as USB. The SMB137B can switch between USB mode and AC Adapter mode and works seamlessly in conjunction with a USB controller. Also the SMB137B can manage two outputs independently: battery charging and system power. This allows immediate system operation even under missing/deeply discharged battery conditions. Also in the case of a low battery and insufficient/missing input supply the SMB137B can run its switching regulator in reverse to support “Low Battery Recovery” mode (+4.17V @ 500mA) or USB “On the Go” power (+5V @ 500mA). Charge control includes input current limit (supporting USB2.0), trickle charge, pre-charge, constant current/constant voltage, float voltage and termination/safety settings that are fully programmable via a serial 2 I C/SMBus and stored in non-volatile memory making the device truly 2 a flexible solution. Fast charge current level can be set via I C (limited by the input current settings). An Enable (EN) pin is also provided for suspending charging and/or sleep mode. Built-in reverse-current blocking prevents inadvertent cell discharge. The SMB137B also offers a wide variety of features that protect the battery pack as well as the charger and input circuitry: over-current, under/over-voltage, safety timers and thermal protection. Accurate 1.0% battery float voltage control ensures complete charging and improves battery capacity utilization. Status can be monitored via the serial port for charge state and fault conditions. In addition, the STAT output can be used to signal charge status. Operating voltage is specified from +4.35V to +6.0V with +18V non-operating input tolerance. The SMB137B is available in an ultra-compact CSP-30 package and is rated over the –30C to +85C temperature range. Applications Portable Media Players Smartphones/PDA’s Digital camcorders/still cameras Handheld GPS SYSTEM APPLICATION Handheld Device AC/DC Adapter up to 1400mA 4.5V-6.0V (18V OVP) System Output up to 1400mA AC/DC Input 700-1400mA LBR Output "Ideal Diode" 4.17V @ 500mA Current USB Input 100/500/700-1400mA VB US D- USB Charger up to 1400mA 4.5V-6.0V (18V OVP) USB-OTG 5.0V @ 500mA Total Sys. Output >1400mA Charging Current up to 1500mA System • • • • SMB137B Li- Ion OTG/LBR 750mA D+ NC GND USB2.0 500mA 4.35V-5.5V I2C (optional) USB Figure 1 – Using the SMB137B to charge a single cell Li+ battery from USB or AC Adapter power sources *Patent Pending © SUMMIT Microelectronics, Inc. 2007 • 757 N. Mary • Sunnyvale CA 94085 • Phone 408 523-1000 • FAX 408 523-1266 http://www.summitmicro.com/ 2137 2.1 7/7/2009 1