DEMO MANUAL DC103 BATTERY CHARGER LT1511 Constant-Voltage/ Constant-Current Lithium-Ion Battery Charger with Input Current Limiting U DESCRIPTIO Demonstration board DC103 is a complete Li-Ion battery ments increase, the LT1511 begins adjusting the battery charger designed for 1-, 2- or 3-cell applications. The LT 1511 charging current downward to keep the input power is used in a high efficiency current mode step-down topology, supply current below a predetermined limit. capable of providing up to 3A of charging current. The Jumpers JP1 and JP2, located on the demo board, are 200kHz switching frequency allows small surface mount used to select the correct charging voltage for the number components to be used, thus minimizing board space and of cells being charged (4.2V, 8.4V or 12.6V). Battery height. The precision voltage required by Li-Ion batteries is charging current is programmed for 3A by resistor R11 programmed by a resistor divider and the maximum battery and the current sense resistors R6, R9 and R15. Maximum charge current is programmed with a single 1/10W resistor input current (or AC adapter current) is set for 3A by (or a programming current from a DAC). current sense resistor R4. A unique feature of the LT1511 is its ability to monitor the Also included on this demo board are a soft start function, input current from the power source, provide current to a undervoltage lockout (with an undervoltage lockout signal load and to adjust the battery charging current accord- out) and provisions for driving the supply boost capacitor ingly, so as not to exceed a predetermined current from the from an external low DC voltage, rather than from the input power source. This allows the input power supply or battery voltage, to increase efficiency and thus reduce AC adapter to provide current to power system circuitry heat dissipation. and simultaneously charge a battery, without overloading , LTC and LT are registered trademarks of Linear Technology Corporation. the input power supply. As the system current require- BOARD PHOTO AND SIMPLIFIED BLOCK DIAGRAM Component Side Simplified Block Diagram of Charger Application LT1511 DEMO BOARD CONSTANT-CURRENT/ CONSTANT-VOLTAGE CHARGER WITH INPUT INPUT CURRENT LIMITING POWER I SOURCE INPUT I LOAD SYSTEM (LOAD) R AC S1 WALL I ADAPTOR BAT BATTERY CHARGE (BEING CHARGED) R CONTROL S2 DM103 F01 1 W W UDEMO MANUAL DC103 BATTERY CHARGER WWU W PERFOR A CE SU ARY PARAMETER CONDITIONS LIMITS V V + 3V V 28V* IN OUT IN Battery Voltage (V)V = 12V 4.2V 0.85% BAT IN When Charging Terminates V = 16V 8.4V 0.85% IN V = 28V 12.6V 0.85% IN Maximum Battery Charging Current 3A 5% *For V > 25V, C1 and C2 should be replaced with a higher voltage rating. IN U WW PACKAGE A D SCHE ATIC DIAGRA S TOP VIEW GND* 1 24 *GND SW 2 23 *GND BOOST 3 22 V CC1 LT1511CSW GND* 4 21 V ALL GND PINS ARE FUSED TO CC2 INTERNAL DIE ATTACH PADDLE GND* 5 20 V CC3 FOR HEAT SINKING TO PC BOARD UV 6 19 PROG USE GENEROUS AMOUNTS OF PC GND* 7 18 V C BOARD COPPER AROUND LEADS OVP 8 17 UV OUT (SEE LT1511 DATA SHEET AND DESIGN NOTE 124) CLP 9 16 *GND CLN 10 15 COMP 2 COMP 1 11 14 BAT SENSE 12 13 SPIN SW PACKAGE 24-LEAD PLASTIC SO WIDE R4 D3 0.033 MBRS340T3 1% V IN TO SYSTEM E3 LOAD D1 MBRS340T3 E2 E2 R5 510 1 24 GND GND ALTERNATE LOCATION R2 3k C3 2 FOR D3, SEE TEXT 23 SW GND 2, 3 5% 0.47F C6 C1, 10F 3 22 BOOST V 1F CC1 L1** 4 21 20H GND V CC2 D2 5 20 1, 4 MBR0540T GND V CC3 C2, 10F 6 19 LT1511 UV PROG R1 7 18 R12 GND V C 5.1k 300 R10 R11 8 17 5% OVP UV OUT 1k 4.93k C4 9 16 C5 CLP GND 1F 0.33F 10 15 CLN COMP 2 PROGRAM OUTPUT VOLTAGE 11 14 E4 COMP 1 BAT BATTERY UV ERROR OUTPUT 12 JP1 JP2 VOLTAGE 13 C7 SENSE SPIN CLOSED CLOSED 4.2V 220pF R6 R * R9 PU CLOSED OPEN 8.4V 200, 1% 200 OPEN OPEN 12.6V 1% JP3 + V R15 NOTE 1: FOR LOWER IC POWER DISSIPATION 0.033 E6 I BAT AND PACKAGE TEMPERATURE, USE EXTERNAL 1% V BAT V (LOWER THAN V ) X BAT JP2 JP1 + *RPU = PULL-UP RESISTOR REQUIRED IF C8 Li-Ion UV LOCKOUT ERROR OUTPUT IS USED. 22F BATTERY + C9 **CTX20-4 E1 10F R7 R8 R13 R14 164k 115k 280k 280k E6 SEE DM103 SCHEMATIC 0.1% 0.1% 0.1% 0.1% V X NOTE 1 Figure 1. Demo Board Schematic 2