Description

The AS3683 is a low-noise, high-current 1A charge pump designed for camera flash LEDs and LCD backlighting applications. The current sinks are capable of driving up to 960mA of load current.

The AS3683 integrates two independent current source blocks for driving a single flash LED (CURR11 to CURR13) with up to 480mA, and general purpose LEDs (CURR2 to CURR4) with up to 160mA/LED. The general purpose LEDs are controlled individually and can be used for backlighting, but also in support of an RGB funlight or a movie indicator lamp. To meet high-flash cur rent requirements (up to 960mA), both current source blocks can be connected together (CURR11 to CURR13 and CURR2 to CURR4).

The AS3683 utilizes austriamicrosystems's patent-pending Intelligent Adaptive Mode Setting (IAMS) to switch between 1:1, 1:1.5, and 1: 2 modes. In combination with very-low-drop-out current sinks, the device achieves high efficiency over the full single-cell Li+ battery voltage range. The charge pump operates at a fixed frequency of 1MHz allowing for tiny external components and its design ensures low EMI and low input-ripple.

The ultra-flexible brightness control scheme allows for simple adaptation of the device to different system architectures.

In Softflash Mode the device is controlled by an I2C interface. In these modes the LED brightness, flash duration, GPIOs and various charge pump states are controlled by internal register settings. The GPIO pins can act as programmable input or output pins and can also be set to trigger preview and flash light directly by a camera module.

In Hardflash mode the LED brightness is controlled by the Enable pins. These programming pins can be used as simple enable pins, or as PWM input, again offering ample flexibility for setting the LED brightness.