LT1512 SEPIC Constant-Current/ Constant-Voltage Battery Charger Fea T Descrip T n Charger Input Voltage May Be Higher, Equal to or The LT 1512 is a 500kHz current mode switching regulator Lower Than Battery Voltage specially configured to create a constant-current/constant- n Charges Any Number of Cells Up to 30V* voltage battery charger. In addition to the usual voltage n 1% Voltage Accuracy for Rechargeable Lithium feedback node, it has a current sense feedback circuit for Batteries accurately controlling output current of a flyback or SEPIC n 500kHz Switching Frequency Minimizes (Single-Ended Primary Inductance Converter) topology Inductor Size charger. These topologies allow the current sense circuit n 100mV Current Sense Voltage for High Efficiency to be ground referred and completely separated from the n Battery Can Be Directly Grounded battery itself, simplifying battery switching and system n Charging Current Easily Programmable or Shut Down grounding problems. In addition, these topologies allow charging even when the input voltage is lower than the battery voltage. a T Maximum switch current on the LT1512 is 1.5A. This allows n Battery Charging of NiCd, NiMH, Lead-Acid or battery charging currents up to 1A for a single lithium-ion Lithium Rechargeable Cells cell. Accuracy of 1% in constant-voltage mode is perfect n Precision Current Limited Power Supply for lithium battery applications. Charging current can be n Constant-Voltage/Constant-Current Supply easily programmed for all battery types. n Transducer Excitation L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. *Maximum Input Voltage = 40V V BAT Typical a T Maximum Charging Current L1 A* WALL 1.0 ADAPTER C2** D1 SINGLE + C3 INPUT 2.2F MBRS130LT3 LITHIUM 22F V IN 0.8 V CELL (4.1V) 25V SW 0.5A CHARGE L1 B* SYNC LT1512 R1 0.6 DOUBLE AND/OR S/S LITHIUM SHUTDOWN FB CELL (8.2V) SHUTDOWN GND GND S V I C FB + C1 R4 R2 0.4 22F 6V BATTERY 24 25V C5 0.1F 12V BATTERY 0.2 R3 R5 C4 0.2 1k 0.22F INDUCTOR = 33H 0 0 5 10 15 20 25 *L1 A, L1 B ARE TWO 33H WINDINGS ON A SINGLE INDUCTOR: COILTRONICS CTX33-3 INPUT VOLTAGE (V) 1512 F01 **TOKIN CERAMIC 1E225ZY5U-C203-F 1512 TA02 ACTUAL PROGRAMMED CHARGING CURRENT w ILL BE INDEPENDENT OF INPUT VOLTAGE AND BATTERy VOLTAGE IF IT DOES NOT ExCEED THE VALUES SHOw N. Figure 1. SEPIC Charger with 0.5A Output Current THESE ARE ELECTRICAL LIMITATIONS BASED ON MAxIMUM Sw ITCH CURRENT. PACKAGE THERMAL LIMITATIONS MAy REDUCE MAxIMUM CHARGING CURRENT. SEE APPLICATIONS INFORMATION. 1512fc 1 For more information www.linear.com/LT1512 CURRENT (A) ion pplica ions pplica ion uresLT1512 a Te Maxi Mu M r a T p in c F T (Note 1) TOP VIEW Input Voltage ........................................................... 30V V V 1 8 C SW Switch Voltage ......................................................... 40V FB 2 7 GND S/S Pin Voltage ........................................................ 30V I 3 6 GND S FB FB Pin Voltage (Transient, 10ms) ........................... 10V S/S V 4 5 IN V Pin Current ..................................................... 10mA FB I Pin Voltage (Transient, 10ms) .......................... 10V N8 PACKAGE S8 PACKAGE FB 8-LEAD PDIP 8-LEAD PLASTIC SO Storage Temperature Range .................. 65C to 150C T = 125C, q = 100C/w (N) JMAx JA Ambient Temperature Range T = 125C, q = 130C/w (S) JMAx JA LT1512C (Note 2) ..................................... 0C to 70C NOTE: CONTACT FACTORy CONCERNING 16-LEAD FUSED-LEAD GN PACKAGE w ITH LOw ER THERMAL RESISTANCE LT1512I ................................................ 40C to 85C Operating Junction Temperature Range LT1512C (Note 2) .............................. 20C to 125C LT1512I .............................................. 40C to 125C Short Circuit.......................................... 0C to 150C Lead Temperature (Soldering, 10 sec) ................. 300C Der in F Ma T LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1512CN8 PBF LT1512CN8 TRPBF 1512 8-Lead PDIP 0C to 70C LT1512CS8 PBF LT1512CS8 TRPBF 1512 8-Lead Plastic SO 0C to 70C LT1512IN8 PBF LT1512IN8 TRPBF 1512I 8-Lead PDIP 40C to 85C LT1512IS8 PBF LT1512IS8 TRPBF 1512I 8-Lead Plastic SO 40C to 85C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT1512CN8 LT1512CN8 TR 1512 8-Lead PDIP 0C to 70C LT1512CS8 LT1512CS8 TR 1512 8-Lead Plastic SO 0C to 70C LT1512IN8 LT1512IN8 TR 1512I 8-Lead PDIP 40C to 85C LT1512IS8 LT1512IS8 TR 1512I 8-Lead Plastic SO 40C to 85C Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container. For more information on lead free part marking, go to: