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Boost converter from AnalogicTech simplifies USB 2.0 host port and On-The-Go operations

17th January 2007

Advanced Analogic Technologies Inc., Europe

ES Admin

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As a growing number of smart phones and other handheld devices operating off a single-cell lithium-ion battery add higher levels of processing power and begin to serve as central computing platforms, users are demanding connectivity to other peripheral devices. By integrating a boost converter with a current-limiting load switch, AnalogicTech’s AAT1275 power management IC allows designers to boost voltage and provide the protection needed to simply and efficiently host a USB port on these new computing-intensive convergent portable systems.

The AAT1275 is a new type of power management IC that combines a 500mA boost converter with a current-limiting load switch. By bringing together a regulated 5V, 500mA output with current limit protection in a single monolithic device, the AAT1275 simplifies the development of host USB ports in portable electronics systems powered from a single-cell Lithium-ion battery.

Operating from a 2.7 to 5V input range, the AAT1275 supports both USB 2.0 host port and USB On-The-Go operation in single-cell Lithium-ion battery powered systems. While the load switch current limit defaults to the standard USB 500mA limit, it can be programmed to lower values to host lower current USB ports, thereby saving precious battery power, or support any application that requires a current-limited 5V supply. To maximise battery life, the boost converter section of the AAT1275 provides efficiency levels of greater than 90 percent across a wide load range. A high 2MHz switching frequency provides fast load transients and minimises the size of external components.

One of the most difficult challenges designers face using conventional boost converters is leakage current. To address this problem, the AAT1275 adds an innovative true load disconnect feature that minimises losses and simplifies design by isolating the load from the power source when the AAT1275 is off.

The integrated programmable current limiting load switch on the AAT1275 provides USB port protection too. An active low fault flag alerts the system when an over-current condition is applied to the AAT1275 output. To ensure device integrity, the AAT1275 also adds over-temperature and over-current protection and inrush current limit capability.

Specified over the -40 to +85 degrees C temperature range, the AAT1275 is available in Pb-free, 2.75 mm X 3 mm 12-pin TSOPJW, and 16-pin TDFN34 style packages.