Diodes releases High Speed Dual channel flash LED drivers

     Diodes announced the AL3644, a high-speed dual-channel flash LED driver designed to support advanced camera flash and flashlight functions for the latest smartphones and other portable consumer devices. Key features include independent control of the output current, which can be set through an I2C compatible interface, and the ability to combine two devices (each with a different device identification address) to drive four leds for up to 6A current in four-channel applications.

     The AL3644 is available in a chip-scale package and combines flexible frequency switching with constant output current. The AL3644 and AL3644TT (representing different device identification addresses) are available in low and high flashlight current versions in a U-WLB1713-12 package with a size of 1.75mm x 1.35mm.

     The AL3644 uses A constant-frequency, synchronous-boost current-mode PWM converter to deliver up to 1.5A to each of the two constant current sources in the input voltage range of 2.5V to 5V. The driver uses an I2C-compatible interface, operating at frequencies up to 400kHz. The device can be configured to provide A constant current in any of 128 segments between 1.4mA and 1.5A. The ratio of the two outputs can also be adjusted via an I2C-compatible interface.

     As the boom in portable and wearable devices continues, which require sophisticated camera functions (including video recording), as well as convenient flashlight functions, the demand for highly flexible LED drivers continues to increase. The AL3644 provides a dual, parallel source of current with an efficiency of more than 85% in both flashlight mode and flash mode to meet this requirement.

     The device offers 2MHz and 4MHz frequency switching options, giving engineers more design flexibility and simplifying the overall design. The higher the switching frequency, the easier it is to use smaller passive components such as low inductors and small 10μF ceramic capacitors, thereby reducing the overall bill of material.

     The AL3644 is Diodes' first LED driver with an I2C compatible interface, as well as an integrated comparator that can be paired with an external NTC to detect heat changes. The input voltage monitor ensures that the output current remains stable, for example in cases where the input voltage drops as the device's battery supply decreases. The fault status bits, which can be queried via the I2C compatible interface, provide the host controller with various operational data, such as flash current timeout, LED overheat, LED open/short circuit failure, overheat shutdown, and input undervoltage.