Archive : 21 December 2007 год

AnalogicTech has introduced the AAT3663 a 1A linear battery charger ICs capable of charging up to two Li-ion cells in series. Designed to operate from either an AC adapter or a USB port, the device features AnalogicTech’s innovative Digital Thermal Loop charge reduction circuit that monitors the internal die temperature and gradually steps down the charge current to avoid thermal shutdown. By supporting input voltages up to 13.2V, the device offers designers the opportunity to replace larger and more expensive discrete charging solutions with a high integrated and more cost effective alternative. The AAT3663 operates across a 4.0V to 13.2V input voltage range and supports user programmable charge current from 100mA up to 1A via an external resistor.

Quiescent current is less than 6microAmps. The device features an intelligent digital thermal loop charge reduction circuit that optimises battery charge rate by constantly measuring die temperature and adjusting the charge current to compensate for thermal conditions. The charger IC features a programmable charge termination current feature that sends the device into sleep mode if the charging current dips below a pre-defined threshold. An integrated programmable charge timer can be used to shut down charging functions if a defective battery cell or a disconnection to the battery current path is detected. The AAT3663 continuously monitors battery temperature and charge state for fault conditions. To protect the charging device and the battery under charge, integrated over-temperature, short-circuit, over-voltage and over-current protection circuits automatically shuts down the device if a fault occurs. Specified for operation across the -40 C to +85 C temperature range, the AAT3663 is available in a thermally enhanced 14-pin, 3x3mm TDFN package.

Maxim introduces the MAX16824/MAX16825 3-channel, high-brightness LED drivers with a 6.5V to 28V input-voltage range. These devices feature three 36V-rated, open-drain, constant-current sink outputs capable of delivering up to 150mA to three separate strings of HB LEDs. For optimal design flexibility, these ICs allow independent LED current setting of each channel. To implement this functionality, the MAX16824 provides three PWM dimming inputs to independently control the brightness of each string of LEDs and switch each string on or off. Conversely, the MAX16825 features a 3-bit transparent latch, a 3-bit shift register, and a 2Mbps, 4-wire serial interface. The serial interface allows all output channels to be controlled through an external microcontroller; it also enables multiple MAX16825 drivers to be cascaded and operated together.