AS3682 - 460mA Flash/Backlight Driver

Description

The AS3682 is a low-noise, three mode charge-pump which combines a high current LED camera flash driver and an general purpose LED driver in one device.

These two independent LED blocks can drive:

• 1 flash LED with up to 480mA
• 2 general purpose LEDs up to 160mA/LED

The general purpose LEDs are controlled individually and can be used for example for backlighting, RGB smart-light or indicator lamp.

The AS3682 charge-pump switches automatically between the 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 battery voltage range. The fixed frequency of 1MHz allows tiny external components and is desiged to ensures low EMI and low input-ripple.

The flexible brightness control scheme makes adaption to different system architectures simple.

The AS3682 integrates an I²C interface, giving full control over settings like LED brightness, flash duration, GPIOs and others. The available GPIO pins can be used for example to trigger the flash directly by a camera module, as PWM inputs or as simple enable control pins.

A configuration called "hardflash mode" simplifies the interface and stears the LED brightness through enable pins directly.

Key Features

• Thre mode high-efficient charge pump (1:1, 1:1.5, 1:2)
  • soft start to reduce Inrush current
  • Low-noise constant frequency operatio
  • Automatic CP mode switchin
• Efficiency up to 95%
• 2 independent LED blocks with 5 current sinks:
  • Flash: 480mA max current
  • General Purpose: 0 to 160mA, fully programmable @ 0.625mA Resolution
• Different operating modes (normal, softflash, hardflash)
• I²C Interface
• General purpose IOs (GPIOs)
• Safety features:
  • Automatic open LED detection
  • Integrated thermal protection
• Smart features:
  • Flexible brighness control
  • Soft start to reduce inrush current
  • Low-noise constant frequency operation
  • LED disconnect in shutdown
• Package:
  • QFN24-Pin, 4x4mm

Applications

• Mobile phones
• Digital Still Cameras (DSC)
• Mobile Internet Devices (MID)

Block diagram for AS3682 - 460mA Flash/Backlight Driver