LT1505 Constant-Current/Voltage High Efficiency Battery Charger FEATURES DESCRIPTIO n Simple Charging of Li-Ion, NiMH and NiCd Batteries The LT 1505 PWM battery charger controller fast charges n Very High Efficiency: Up to 97% multiple battery chemistries including lithium-ion (Li-Ion), n Precision 0.5% Charging Voltage Accuracy nickel-metal-hydride (NiMH) and nickel-cadmium (NiCd) n Preset Battery Voltages: 12.3V, 12.6V, using constant-current or constant-voltage control. Maxi- 16.4V and 16.8V mum current can be easily programmed by resistors or a n 5% Charging Current Accuracy DAC. The constant-voltage output can be selected for 3 or 4 n Charging Current Programmed by Resistor or DAC series Li-Ion cells with 0.5% accuracy. n 0.5V Dropout Voltage, Duty Cycle > 99.5% A third control loop limits the current drawn from the AC n AC Adapter Current Limit* Maximizes Charging Rate adapter during charging*. This allows simultaneous opera- n Flag Indicates Li-Ion Charge Completion tion of the equipment and fast battery charging without over- n Auto Shutdown with Adapter Removal loading the AC adapter. n Only 10m A Battery Drain When Idle n The LT1505 can charge batteries ranging from 2.5V to 20V Synchronizable Up to 280kHz with dropout voltage as low as 0.5V. Synchronous U N-channel FETs switching at 200kHz give high efficiency APPLICATIO S and allow small inductor size. A diode is not required in series with the battery because the charger automatically n Notebook Computers enters a 10m A sleep mode when the wall adapter is un- n Portable Instruments plugged. A logic output indicates Li-Ion full charge when n Chargers for Li-Ion, NiMH, NiCd and Lead Acid current drops to 20% of the programmed value. Rechargeable Batteries The LT1505 is available in a 28-pin SSOP package. , LTC and LT are registered trademarks of Linear Technology Corporation. *US Patent No. 5,723,970 TYPICAL APPLICATION TO M3 SYSTEM POWER Si4435 C4 DBODY* D3 R 0.1m F S4 MMSD4148T1 V 0.025W IN (FROM C IN V BOOST BOOSTC CC C2 ADAPTER) C3 D2 C1 47m F R7 2.2m F 0.68m F MMSD4148T1 1m F GBIAS 35V 500W L1 M1 R S1 CLN TGATE 100k Si4412 15m H 0.025W 5W CLP SW V BAT R5 M2 D4 C OUT INFET BGATE 4k 22m F 12.6V Si4412 MBRS140 25V BATTERY UV V C 2 R6 SYNC PROG LT1505 4k SHDN 3 CELL R 300 X4 3k FLAG V FB R R C S2 S3 PROG 0.33m F 200W 200W 1m F CAP 4.2V *BODY DIODE 1% 1% R POLARITY MUST PROG COMP1 4.1V BE AS SHOWN 4.93k R1 1% AGND 1k * DBODY IS THE BODY DIODE OF M3 C6 C7 PGND C : SANYO OS-CON IN 0.1m F 0.68m F L1: SUMIDA CDRH127-150 BAT2 BAT SENSE SPIN (CAN BE FROM 10H TO 30H) 1505 F01 Figure 1. Low Dropout 4A Lithium-Ion Battery Charger 1505fc 1 U ULT1505 ABSOLUTE MAXIMUM RATINGS (Note 1) V , CLP, CLN, INFET, UV, 3CELL, FLAG................ 27V TGATE, BGATE Current Continuous ....................... 0.2A CC SW Voltage with Respect to GND ........................... 2V TGATE, BGATE Output Energy (per cycle) ............... 2m J BOOST, BOOSTC Voltage with Respect to V ....... 10V Maximum Operating V ......................................... 24V CC CC GBIAS ..................................................................... 10V Operating Ambient Temperature Range ....... 0 C to 70 C SYNC, BAT2, BAT, SENSE, SPIN ............................ 20V Operating Junction Temperature Range .... 0 C to 125 C V , PROG, V , 4.1V, 4.2V ........................................ 7V Storage Temperature Range ................. 65 C to 150 C C FB CAP, SHDN .......................................................... 3mA Lead Temperature (Soldering, 10 sec).................. 300 C PACKAGE/ORDER INFORMATION TOP VIEW TOP VIEW ORDER PART ORDER PART 1 28 PGND 1 28 PGND NUMBER BOOST NUMBER BOOST 2 BGATE TGATE 27 TGATE 2 27 BGATE SW 3 26 GBIAS 3 26 GBIAS SW LT1505CG LT1505CG-1 4 BOOSTC SYNC 25 SYNC 4 25 BOOSTC SHDN 5 24 V 5 24 V CC SHDN CC 6 23 BAT 6 AGND AGND 23 BAT UV 7 22 SPIN UV 7 22 SPIN 8 21 SENSE 8 SENSE INFET INFET 21 CLP 9 20 BAT2 NC 9 20 BAT2 10 19 PROG 10 19 PROG CLN NC 11 V COMP1 18 GND 11 18 V C C CAP 12 17 V 12 17 V FB CAP FB 13 3CELL FLAG 16 FLAG 13 16 3CELL 4.1V 14 15 4.2V 14 15 4.2V 4.1V G PACKAGE G PACKAGE NOTE: LT1505CG-1 DOES NOT 28-LEAD PLASTIC SSOP 28-LEAD PLASTIC SSOP HAVE INPUT CURRENT T = 125 C, q = 100 C/ W T = 125 C, q = 100 C/ W JMAX JA JMAX JA LIMITING FUNCTION. Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The l denotes specifications which apply over the full operating temperature range, otherwise specifications are at T = 25 C. V = 18V, V = 12.6V, V = V (LT1505), no load on any A CC BAT CLN CC outputs unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Overall Supply Current V 24V l 12 15 mA CC Sense Amplifier CA1 Gain and Input Offset Voltage 11V V 24V , 0V V 20V CC BAT (With R = 200W , R = 200W)R = 4.93k 95 100 105 mV S2 S3 PROG (Measured across R , Figure 1) (Note 2) R = 4.93k l 92 108 mV S1 PROG R = 49.3k 7 10 13 mV PROG BOOST Pin Current V = V + 8V, 0V V 20V BOOST SW SW TGATE High 2 3 mA TGATE Low 2 3 mA BOOSTC Pin Current V = V + 8V 1 mA BOOSTC CC Reference Reference Voltage (Note 3) R = 4.93k, Measured at V with V 2.453 2.465 2.477 V PROG FB A Supplying I and Switching Off PROG Reference Voltage Tolerance 11V V 24V l 2.441 2.489 V CC 1505fc 2 U W U U WWW