Milpitas, Calif. - When interfaced with a microcontroller, Linear Technology Corp.'s LTC4008, a 4-amp multicell, multichemistry battery pack charger IC, is said to be capable of charging nickel cadmium, nickel metal hydride and sealed lead-acid batteries as well as lithium-ion types.
The general-purpose controller enables high-power battery charger designs of only 5.6 cm2, which according to LTC is 50 percent smaller than conventional high-power battery charger designs. In addition, high-efficiency operation from high input voltage and low-dropout power conversion allows a designer to optimize the choice of an ac/dc adapter based on size, cost and weight, the company said.
The LTC4008 uses I/O signals for simple reporting of the system status. A microcontroller can then use the same signals for precision gas gauging, power management and comprehensive display of the charging condition. The charger chip drives external MOSFETs synchronously to achieve over 95 percent efficiency even when operating from high input voltage and delivering up to 4 A of charge current, LTC said.
Charging current is programmable to plus/minus 4 percent accuracy with external resistors. The device's ac adapter current limit allows an end product to operate simultaneously as the battery pack is being charged at the maximum rate without overloading the ac adapter. A thermistor sensor input will suspend charging if an unsafe temperature condition is detected and will automatically resume charging when battery temperature returns to within safe limits. The input voltage range is 6 to 28 V; the output range is 3 to 28 V.
The LTC4008 is packaged in a 20-pin SSOP. In lots of 1,000, pricing starts at $3.70. A data sheet can be found at www.linear.com/prod/data
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