LTC1759 Smart Battery Charger FEATURES DESCRIPTIO n Single Chip Smart Battery Charger Controller The LTC 1759 Smart Battery Charger is a single chip n 100% Compliant (Rev 1.0) SMBus Support charging solution that dramatically simplifies construc- Allows for Operation with or without Host tion of an SBS compliant system. The LTC1759 imple- n SMBus Accelerator Improves SMBus Timing ments a Level 2 charger function whereby the charger can n Hardware Interrupt and SMBAlert Response be programmed by the battery or by the host. A thermistor Eliminate Interrupt Polling on the battery being charged is monitored for tempera- n High Efficiency Synchronous Buck Charger ture, connectivity and battery type information. The SMBus n 0.5V Dropout Voltage Maximum Duty Cycle > 99.5% interface remains alive when the AC power adapter is n AC Adapter Current Limit Maximizes Charge Rate* removed and responds to all SMBus activity directed to it, n 1% Voltage Accuracy 5% Current Accuracy including thermistor status (via the ChargerStatus com- n Up to 8A Charging Current Capability mand). The charger also provides an interrupt to the host n Dual 10-Bit DACs for Charger Voltage and Current whenever a status change is detected (e.g., battery Programming removal, AC adapter connection). n User-Selectable Overvoltage and Overcurrent Limits Charging current and voltage are restricted to chemistry n High Noise Immunity Thermistor Sensor specific limits for improved system safety and reliability. n Small 36-Lead Narrow (0.209 ) SSOP Package Limits are programmable by two external resistors. Addi- U tionally, the maximum average current from the AC adapter APPLICATIO S is programmable to avoid overloading the adapter when n simultaneously supplying load current and charging cur- Portable Computers n rent. When supplying system load current, charging cur- Portable Instruments n rent is automatically reduced to prevent adapter overload. Docking Stations , LTC and LT are registered trademarks of Linear Technology Corporation. *US Patent Number 5,723,970 TYPICAL APPLICATIO 15.8k 1k 0.033 AC + 10F 0.1F ADAPTER LTC1759 35V INPUT V 7 22 DD Al UV 499 DCIN 0.1F 16 21 V DCDIV DD 0.47F 8 SYSTEM 4 SYNC INFET POWER 5 32 1F SDB V CC 12 9 22F CHGEN CLP 33k 25 10 V LIMIT CLN 33k 24 2 0.1F I TGATE 2.2F LIMIT 33 18 DGND 15H 0.025 BOOSTC 3.83k 17 34 0.68F I GBIAS SET + 1F 28 1 22F PROG BOOST SMART 0.33F 1.5k 27 3 BATTERY V C SW 0.68F 1k 11 35 COMP1 BGATE 30 6 AGND SPIN 200 20 29 RNR SENSE 19 31 200 THERM BAT1 V DD 14 23 SDA BAT2 68 15 26 SCL V SET 475k 10k 1k 36 13 0.047F INTB PGND 0.015F SMBus INTB SCL TO SDA HOST 1759 F01 Figure 1. 4A SMBus Smart Battery Charger 1 U ULTC1759 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) TOP VIEW ORDER PART Voltage at V , UV, BAT1, CLP,CLN, SPIN, CC BOOST 1 36 PGND NUMBER SENSE with respect to AGND ....................0.3V to 27V TGATE 2 35 BGATE Voltage at DCIN, BAT2 with Respect SW 3 34 GBIAS to DGND ....................................................0.3V to 27V SYNC 4 33 BOOSTC LTC1759CG SDB 5 32 V CC Voltage at INTB, SDA, SCL, DCDIV with Respect AGND 6 31 BAT1 to DGND ..................................................... 0.3V to 7V UV 7 30 SPIN BOOST, BOOSTC Voltage with Respect to V ........ 10V CC INFET 8 29 SENSE Voltage at V with Respect to DGND ........ 0.3V to 7V CLP 9 28 PROG DD CLN 10 27 V C SW Voltage with Respect to AGND .............. 2V to V CC COMP1 11 26 V SET GBIAS, SYNC ............................................ 0.3V to 10V CHGEN 12 25 V LIMIT V , PROG, V Voltage with Respect C SET INTB 13 24 I LIMIT SDA 14 23 BAT2 to AGND ......................................................0.3V to 7V SCL 15 22 DCIN TGATE, BGATE Current Continuous .................. 200mA V 16 21 DCDIV DD TGATE, BGATE Output Energy (per Cycle) ................ 2m J I 17 20 RNR SET PGND, DGND with Respect to AGND .................... 0.3V DGND 18 19 THERM Current into Any Pin ......................................... 100mA G PACKAGE 36-LEAD PLASTIC SSOP Operating Ambient Temperature Range ...... 0 C to 70 C Operating Junction T = 125 C, q = 85 C/ W JMAX JA Temperature Range .............................. 40 C to 125 C Consult factory for Industrial and Military grade parts. Storage Temperature ........................... 65 C to 150 C Lead Temperature (Soldering, 10 sec)................. 300 C ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range (T = 0 C to 100 C), otherwise specifications are J T = 25 C. V = DCIN = 18V, V = 12.6V, V = 3.3V unless otherwise specified. A CC BAT1, 2 DD PARAMETER CONDITIONS MIN TYP MAX UNITS Supply and Reference DCIN, V Operating Voltage l 11 24 V CC V Operating Current V 24V l 12 20 mA CC CC DCIN Operating Current V = 24V l 85 150 m A DCIN UV Lockout Threshold Voltage on UV Pin Rising l 6.3 6.7 7.25 V UV Pin Input Current 0V V 8V l 1 5 m A UV Battery Discharge Current V 0.4V, All Connected Pins 40 80 m A UV V Operating Voltage l 3.0 5.5 V DD V Operating Current Charging, V = 5.5V, Shorted Thermistor 1.35 2 mA DD DD Not Charging, V = 5.5V 80 150 m A DD V Undervoltage Lockout l 1.6 2.2 2.9 V DD Switching Regulator Charging Voltage Accuracy (Notes 3, 5) 2.465V V V l 1 1 % BAT2 MAX Charging Current Accuracy (Note 3) R Tolerance = 1% 5 5 % SET 2 U W U W U WW