LT1511 Constant-Current/ Constant-Voltage 3A Battery Charger with Input Current Limiting FEATURES DESCRIPTIO n The LT 1511 current mode PWM battery charger is the Simple Design to Charge NiCd, NiMH and Lithium simplest, most efficient solution to fast charge modern Rechargeable BatteriesCharging Current rechargeable batteries including lithium-ion (Li-Ion), nickel- Programmed by Resistors or DAC n metal-hydride (NiMH) and nickel-cadmium (NiCd) that Adapter Current Loop Allows Maximum Possible require constant-current and/or constant-voltage charg- Charging Current During Computer Use n ing. The internal switch is capable of delivering 3A* DC Precision 0.5% Accuracy for Voltage Mode Charging n current (4A peak current). Full-charging current can be High Efficiency Current Mode PWM with 4A Internal programmed by resistors or a DAC to within 5%. With 0.5% Switch n reference voltage accuracy, the LT1511 meets the critical 5% Charging Current Accuracy n constant-voltage charging requirement for Li-Ion cells. Adjustable Undervoltage Lockout n Automatic Shutdown When AC Adapter is Removed A third control loop is provided to regulate the current n Low Reverse Battery Drain Current: 3A drawn from the AC adapter. This allows simultaneous n Current Sensing Can Be at Either Terminal of the Battery operation of the equipment and battery charging without n Charging Current Soft-Start overloading the adapter. Charging current is reduced to n Shutdown Control keep the adapter current within specified levels. U The LT1511 can charge batteries ranging from 1V to 20V. APPLICATIO S Ground sensing of current is not required and the batterys negative terminal can be tied directly to ground. A saturat- n Chargers for NiCd, NiMH, Lead-Acid, Lithium ing switch running at 200kHz gives high charging effi- Rechargeable Batteries ciency and small inductor size. A blocking diode is not n Switching Regulators with Precision Current Limit required between the chip and the battery because the chip goes into sleep mode and drains only 3A when the , LTC and LT are registered trademarks of Linear Technology Corporation. *See LT1510 for 1.5A Charger wall adapter is unplugged. D3 R7 MBRD340 TYPICAL APPLICATIO 500 V (ADAPTER INPUT) IN GND CLP 11V TO 28V R S4 C1 ADAPTER 1F CURRENT SENSE SW CLN C2 TO MAIN D1 V CC + + SYSTEM POWER 0.47F MBRD340 C * R5 IN BOOST 10F 10F UNDERVOLTAGE L1** LT1511 20H LOCKOUT COMP1 UV D2 MBR0540T 200pF R6 PROG 5k V SPIN 300 C R PROG 4.93k OVP SENSE BAT 1k C PROG 1% 1F R R S3 S2 NOTE: COMPLETE LITHIUM-ION CHARGER, 0.33F 200 200 NO TERMINATION REQUIRED. R , R7 S4 1% 1% AND C1 ARE OPTIONAL FOR I LIMITING IN V BAT *TOKIN OR UNITED CHEMI-CON/MARCON R3 R S1 + C OUT CERAMIC SURFACE MOUNT 4.2V 390k 0.033 22F 2 Li-Ion **20H COILTRONICS CTX20-4 0.25% BATTERY CURRENT TANT 4.2V SEE APPLICATIONS INFORMATION FOR BATTERY SENSE INPUT CURRENT LIMIT AND UNDERVOLTAGE LOCKOUT 1511 F01 VOLTAGE SENSE R4 162k 50pF 0.25% Figure 1. 3A Lithium-Ion Battery Charger 1 + + U ULT1511 ABSOLUTE MAXIMUM RATINGS PACKAGE/ORDER INFORMATION (Note 1) Supply Voltage TOP VIEW ORDER PART (V , CLP and CLN Pin Voltage) ...................... 30V MAX GND** 1 24 GND** NUMBER Switch Voltage with Respect to GND ...................... 3V SW 2 23 GND** Boost Pin Voltage with Respect to V ................... 25V LT1511CSW CC BOOST 3 22 V * CC1 LT1511ISW Boost Pin Voltage with Respect to GND ................. 57V GND** 4 21 V * CC2 Boost Pin Voltage with Respect to SW Pin .............. 30V *ALL V PINS SHOULD CC GND** 5 20 V * CC3 BE CONNECTED V , PROG, OVP Pin Voltage ...................................... 8V UV 6 19 PROG TOGETHER CLOSE TO C THE PINS I (Average)........................................................... 3A GND** 7 18 V C BAT ** ALL GND PINS ARE FUSED TO INTERNAL DIE OVP 8 17 UV Switch Current (Peak) .............................................. 4A OUT ATTACH PADDLE FOR CLP 9 16 GND** Operating Junction Temperature Range HEAT SINKING. CONNECT THESE PINS TO CLN 10 15 COMP2 Commercial ........................................... 0C to 125C EXPANDED PC LANDS COMP1 11 14 BAT FOR PROPER HEAT Industrial ......................................... 40C to 125C SINKING. 30C/W SENSE 12 13 SPIN THERMAL RESISTANCE Operating Ambient Temperature ASSUMES AN INTERNAL SW PACKAGE Commercial ............................................ 0C to 70C GROUND PLANE 24-LEAD PLASTIC SO WIDE DOUBLING AS A HEAT Industrial ........................................... 40C to 85C T = 125C, = 30C/ W** SPREADER JMAX JA Storage Temperature Range ................. 65C to 150C Consult factory for Military grade parts. Lead Temperature (Soldering, 10 sec).................. 300C ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25C. V = 16V, V = 8V, V (maximum operating V ) = 28V, A CC BAT MAX CC R = R = 200 (see Block Diagram), V = V . No load on any outputs unless otherwise noted. S2 S3 CLN CC PARAMETER CONDITIONS MIN TYP MAX UNITS Overall Supply Current V = 2.7V, V 20V l 4.5 6.8 mA PROG CC V = 2.7V, 20V < V 25V l 4.6 7.0 mA PROG CC Sense Amplifier CA1 Gain and Input Offset Voltage 8V V 25V , 0V V 20V CC BAT (With R = 200, R = 200)R = 4.93k l 95 100 105 mV S2 S3 PROG (Measured across R )(Note 2) R = 49.3k l 810 12 mV S1 PROG T < 0C 7 13 mV J V = 28V, V = 20V CC BAT R = 4.93k l 90 110 mV PROG R = 49.3k l713 mV PROG T < 0C 6 14 mV J V Undervoltage Lockout (Switch OFF) Threshold Measured at UV Pin l 678 V CC UV Pin Input Current 0.2V V 8V l 0.1 5 A UV UV Output Voltage at UV Pin In Undervoltage State, I = 70A l 0.1 0.5 V OUT UVOUT UV Output Leakage Current at UV Pin 8V V , V = 5V l 0.1 3 A OUT UV UVOUT Reverse Current from Battery (When V Is V 20V, V 0.4V 3 15 A CC BAT UV Not Connected, V Is Floating) SW 2 UUW U WWW