LT1512 Datasheet | Linear Technology

LT1512 SEPIC Constant-Current/ Constant-Voltage Battery Charger Features n Charger Input Voltage May Be Higher, Equal to or Lower Than Battery Voltage n Charges Any Number of Cells Up to 30V- n 1% Voltage Accuracy for Rechargeable Lithium Batteries n 500k Hz Switching Frequency Minimizes Inductor Size n 100m V Current Sense Voltage for High Efficiency n Battery Can Be Directly Grounded n Charging Current Easily Programmable or Shut Down Applications n Battery Charging of Ni Cd, Ni MH, Lead-Acid or Lithium Rechargeable Cells n Precision Current Limited Power Supply n Constant-Voltage/Constant-Current Supply n Transducer Excitation - Maximum Input Voltage = 40V - VBAT Description The LT®1512 is a 500k Hz current mode switching regulator specially configured to create a constant-current/constantvoltage battery charger. In addition to the usual voltage feedback node, it has a current sense feedback circuit for accurately controlling output current of a flyback or SEPIC (Single-Ended Primary Inductance Converter) topology charger. These topologies allow the current sense circuit to be ground referred and pletely separated from the battery itself, simplifying battery switching and system grounding problems. In addition, these topologies allow charging even when the input voltage is lower than the battery voltage. Maximum switch current on the LT1512 is 1.5A. This allows battery charging currents up to 1A for a single lithium-ion cell. Accuracy of 1% in constant-voltage mode is perfect for lithium battery applications. Charging current can be easily programmed for all battery types. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. Typical Application WALL ADAPTER INPUT + C3 22µF CHARGE 25V SYNC AND/OR SHUTDOWN SHUTDOWN - L1 A- VIN VSW C2- - D1 2.2µF MBRS130LT3 L1 B- S/S FB - GND GND S VC C5 0.1µF R4 24Ω R5 1k C4...