SMB135

SMB135 Advanced Information Programmable, USB/AC, Switch-Mode Battery Charger FEATURES & APPLICATIONS • Programmable USB/AC Li-Ion battery charger • High-efficiency current-mode PWM controller • • • • o o 750kHz to 1.25MHz switching frequency 0% to 100% duty-cycle INTRODUCTION The SMB135 is a programmable single-cell lithium-ion/lithium-polymer battery charger for a variety of portable applications. The device provides a simple and efficient way to charge high-capacity Li-Ion batteries via a USB port or an AC adapter. Unlike conventional devices, the SMB135’s high-efficiency operation eliminates large internal temperature rise and localized hot spot in handheld equipment. Charge control includes qualification, trickle-charge, pre-charge, constant current/constant voltage, and termination/safety settings that are fully programmable via a serial I2C/SMBus making the device truly a flexible solution. Fast charge current level (one or five unit loads) can be set via I2C or an input pin (USB500/100). An Enable (EN) pin is also provided for suspending USB charging and allowing the device to work in parallel with AC charger, which may already be integrated into a PMIC device. In this case, the SMB135 does not allow current to flow back to the USB port. The SMB135 offers a wide variety of features that protect the battery pack as well as the charger and input circuitry: over-current, under/over-voltage and thermal protection. Ultra-precise, 1% accurate, Kelvin-sensed ADOC™ technology allows accurate control of battery float voltage and improves battery capacity utilization. Status can be monitored via the serial port for charge state and fault conditions. In addition, one LED driver output can be used to signal charge status. As a protection mechanism, when the junction temperature approaches approximately 145°C, the PWM switcher will start to cut back on the duty cycle, to reduce current. The SMB135 is available in a space-saving 1.3mm x 2.1mm uCSP package with lead-free balls and is rated over the -30°C to +85°C temperature range. TM 4.35 to 6.0V input voltage range TM Small 1.3 x 2.1 uCSP -15 package (0.4mm pitch) High-accuracy output voltage regulation: 1% Low reverse leakage current • Digital programming of all major parameters via I2C interface (with several addresses) and non-volatile memory o o o o o Battery voltage set point Pre-charge, fast charge, termination current Fast charge voltage threshold Temperature limits Automatic restart threshold • Status indicator • Stability with ceramic capacitors • Wide range of protection features o o Thermal monitor Input/output over-voltage lockout Applications • • • • • GSM Handsets UMTS Handsets Portable Media Players Digital camcorders/still cameras Handheld GPS/PDA’s SIMPLIFIED APPLICATIONS DRAWING SMB135 IN 4.7uF 6.8uH OUT SENSEH SENSEL 10uF 500-700mA 4.35V-6.0V GND D+ D- VDDCAP 1uF 50-100mΩ SDA SCL USB500/100 EN ADC+ ADCCcomp Rcomp BATT Li-Ion THERM STAT GND USB Controller RLIM LED VDC COMP Figure 1 – Applications block diagram featuring the SMB135 programmable switch-mode battery charger. © SUMMIT Microelectronics, Inc. 2006 • 1717 Fox Drive • San Jose CA 95131 • Phone 408 436-9890 • FAX 408 436-9897 http://www.summitmicro.com/ 2106 1.3 2/21/2006 1