Battery Charger has adjustable charge current termination.

Press Release Summary:




Housed in 3 x 3 x 0.75 mm DFN package, LTC4068 standalone, linear, single-cell Li-Ion Lithium Polymer battery charger allows users to program charge cycle termination with system load concurrently applied to battery. Via one resistor, charge termination current can be accurately set to value of less than, more than, or equal to C/10. Thermal regulation scheme maximizes charger rate without risk of overheating. Unit charges directly from USB port.



Original Press Release:



950mA Linear Li-Ion Battery Charger with Adjustable Charge Current Termination Prevents Overcharging



MILPITAS, CA - April 19, 2004 - Linear Technology Corporation introduces the LTC4068, a standalone linear single-cell Li-Ion Lithium Polymer battery charger that allows system designers to program charge cycle termination properly with a system load concurrently applied to the battery. In some cases, the system load demands so much current that the charge current termination threshold is never reached and the charge cycle continues indefinitely, overcharging the battery. Potential harmful effects of this condition are reduced battery life, thermal runaway and possible permanent damage to the cell. The LTC4068 eliminates these risks by enabling adjustment of the level of charge termination current relative to the amount of current needed by the system during battery charging.

With the use of a single resistor, charge termination current can be accurately set to a value less than, more than or equal to C/10. Moreover, the LTC4068 is equipped with a patented thermal regulation scheme, which maximizes charger rate without the risk of overheating. As a standalone charger, it features a charge current monitor, trickle charge for battery pre-conditioning, undervoltage lockout, automatic recharge, charge status indicator, and input voltage detection/indicator. Applications include PDAs, lightweight portable medical and test equipment and large color screen cell phones.

The LTC4068 is offered in a low profile (0.75mm) 3mm x 3mm DFN (lead-less) package. The total solution footprint is less than 25mm2 since an external MOSFET, sense resistor and blocking diode are not required. The LTC4068 can also charge a Li-Ion battery from a USB port. To preserve battery energy, the LTC4068 draws only 6uA from the battery terminal in standby and 2uA in shutdown mode. Furthermore, to ensure safety at turn on, the IC's soft-start function limits the inrush current. The LTC4068 is also equipped with a 1ms filter to ensure that transient loads created by switching regulators, for example, do not force premature charge cycle termination.

The LTC4068 is rated for operation from -40°C to 85°C. 1,000-piece pricing for the LTC4068 begins at $1.70 each.

Summary of Features: LTC4068

Programmable Charge Termination up to 950mA

Standalone Charger in 3mm x 3mm DFN Package

Thermal Regulation Maximizes Charge Rate without Risk of Overheating

Charges Directly from a USB Port

No MOSFET, Sense Resistor or Blocking Diode Required

Company Background

Linear Technology Corporation was founded in 1981 as a manufacturer of high performance linear integrated circuits. Linear Technology products include operational, instrumentation and audio amplifiers; voltage regulators,power management devices, DC-DC converters and voltage references; comparators; monolithic filters; communications interface circuits; one-chip data acquisition sub-systems; pulse-width modulators and sample-and-hold devices; and high frequencydevices. Applications for Linear Technology's high performance circuits include wireless and broadband telecommunications infrastructure, cellular telephones, networking products and satellite systems, notebook and desk top computers, computer peripherals, video/multimedia, industrial and medical instrumentation, automotive electronics, factory automation, process control, military and space systems, and high-end consumer products including digital cameras, MP3 players and other electronic products.

Note: LT, AND LTC are registered trademarks of Linear Technology Corp.

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