SMB137B preliminary information ? 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 programmable switching li+ battery charger with usb/ac input, currentpath? manager, turbochar g e tm mode*, low batter y recover y *, aicl* and usb on-the-go su pp ort 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 from ac adapter using proprietary ?turbocharge tm 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% ? digital programming of all major parameters via i 2 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 applications ? portable media players ? smartphones/pda?s ? digital camcorders/still cameras ? handheld gps the SMB137B is a programmable single-cell lithium-ion/lithium- polymer battery charger designed for a variety of portable applications. the device provides a simple and e fficient 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 revers e 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 i 2 c/smbus and stored in non-volatile memory making the device truly a flexible solution. fast charge current level can be set via i 2 c (limited by the input current settings). an e nable (en) pin is also provided for suspending charging and/or sleep m ode. 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 faul t conditions. in addition, the stat output can be used to signal char ge status. operating voltage is specified from +4.35v to +6.0v with +18v non-operating input tolerance. the SMB137B is ava ilable in an ultra-compact csp-30 package and is rated over the ?30c to +85c temperature range. system application features & applications handheld device usb2.0 500ma 4.35v-5.5v usb charger up to 1400ma 4.5v-6.0v (18v ovp) i2c (optional) system SMB137B li- ion charging current up to 1500ma usb system output up to 1400ma gnd vb us d- d+ nc usb-otg 5.0v @ 500ma ac/dc adapter up to 1400ma 4.5v-6.0v (18v ovp) otg/lbr 750ma ac/dc input 700-1400ma usb input 100/500/700-1400ma "ideal diode" current total sys. output >1400ma lbr output 4.17v @ 500ma figure 1 ? using the SMB137B to charge a single cell li+ battery from usb or ac adapter power sources *patent pending
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