IC USB external battery charger LED, fault detection

Technologies (Advanced Analogic) recently launched a new battery charger IC, designed to run through the USB port input. As a part of analogictech BatteryManager product series, AAT3688 has an innovative charge reduction loop (charge reduction loop), the automatic monitoring of USB port voltage and current in the dynamic adjustment of the battery, shorten the charging time.

AAT3688 integrates a charging device, a reverse blocking diode and a current sensing circuit in a small 3mm * 3mm TDFN package. The input voltage range of the device is 4V to 5.5V, which is designed to regulate the voltage and current of 4.2V lithium ion / polymer battery.

The charging current of the AAT3688 can be designed as two different levels between 50mA and 500mA - USB High and USB Low, depending on the port type.

In order to ensure safety and reliability of the system, AAT3688 also provides a number of security features, including the ability to monitor the battery temperature and charge state to detect faults. If the voltage or temperature is too high, the device will automatically shut down to protect the charging device, control system and battery in charge state. The status monitor output pin can be used to directly drive two external LED to display the battery status.

At the same time, AAT3688 also includes a serial interface output, if any one of the 14 conditions occur, then report to the MCU. Ogren, a research manager at Erik, a logic product manager, explains: "at present, more and more portable devices are designed to rely on the USB port. Therefore, it is not a trivial task for designers to determine the USB power supply that is required for other functions of portable devices. Designers often use extreme methods to subjectively determine the worst case to maintain the integrity of the port and the amount of current required to protect the host system. AAT3688 charge reduction function simplifies the work, and through automatic voltage sag (voltage sag) to reduce the charging current mode of regulation and other functions when the host device consumes more power, users can more quickly and effectively through the USB port charging terminal."

The use of lead-free, 12 pin 3mm x 3mm TDFN package has been on sale, the applicable temperature range of -40 degrees Celsius to 85 degrees Celsius, priced at $1.09 per 1000.