Dual Path Device Automatically Routes Power from Battery to System When Load Requirements Exceed Adapter Capabilities
"In a number of situations, such as when a GPS-enabled GPRS phone switches zones, a cellular handset or portable system may require more current than the power adapter can deliver," explains Siamak Bastami, product line director for AnalogicTech. "Typically designers compensate for this possibility by using a larger, more expensive adapter or requiring intervention and control by the system processor. To address this problem and avoid a power interruption and system reset, the AAT3672 offers a single, highly integrated solution, delivering additional power as required from the battery."
Dynamic Power Sourcing
The AAT3672 is a single input dynamic battery charger and control IC, compatible with either an AC power adapter or a USB port power source. Dynamic power control allows the device to charge a single-cell Li-on battery and power a system load simultaneously. The device regulates battery charge current and voltage for 4.2V Li-on battery cells. Battery charge current can be programmed up to 1.6A.
Three internal switches on the device provide dynamic power sourcing to the system load. If the system load exceeds the input current supply from the input source, the AAT3672 supplies additional current from the battery cell. The device automatically manages distribution of power between the source, the battery and the system simultaneously to support all power needs , charging the battery cell with the maximum amount of current possible.
To help minimize charge time and protect an input source from overload, the AAT3672 features an automatic battery charge current reduction loop that automatically compensates for voltage sags and throttles back the charge current when the input source cannot provide the required load current. This feature protects the charger, system and source supply if an adapter or power source cannot meet the programmed ADP charging mode current demand.
The AAT3672 also features an intelligent thermal loop control system that continuously measures internal circuit die temperature and automatically reduces fast charge current when the device exceeds a preset internal temperature threshold. By automatically monitoring circuit die temperature and adjusting fast charge current as die temperature changes, this function helps optimize charging by maximizing charge current under given temperature conditions.
The new charger/system management IC also offers a number of protection features including battery over-voltage, over-current and over-temperature protections circuits. It also adds system load current limiting capability.
Price and Availability
Qualified across the -40 degrees C to +85 degrees C temperature range, the AAT3672 is available in a compact 14-pin, 3 x 3-mm TDFN package. The IC sells for $0.95 in 1K quantities.
Advanced Analogic Technologies, Inc. (AnalogicTech) is a supplier of Total Power Management(TM) semiconductor solutions for mobile consumer electronic devices, such as wireless handsets, notebook and tablet computers, smartphones, digital cameras, wireless LAN, and personal media players. The company focuses its design and marketing efforts on the application-specific power management needs of consumer, communications, and computing applications in these rapidly evolving devices. AnalogicTech also develops and licenses device, process, package, and application-related technology. AnalogicTech is headquartered in Santa Clara, California and Macau, S.A.R., with offices in China (Beijing, Shanghai and Shenzhen), Hong Kong, Taiwan, Japan, South Korea, Sweden, France and United Kingdom, as well as a worldwide network of sales representatives and distributors. The company is listed on the NASDAQ exchange under the ticker symbol AATI. For more information, please visit the AnalogicTech website: http://www.analogictech.com. (AnalogicTech - G)
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