AS3682 Datasheet, PDF (1/43 Pages) ams AG – 480mA Camera Lighting Management Unit

austriamicrosystems
AS3682
480mA Camera Lighting Management Unit
Data Sheet
1 General Description
The AS3682 is a low-noise, high-current charge pump
designed for camera flash LEDs and LCD backlighting
applications. The device is capable of driving up to
480mA of load current.
The AS3682 integrates two independent LED 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 fun-light or a
movie indicator lamp.
The AS3682 utilizes austriamicrosystems' patent-pend-
ing 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 archi-
tectures.
In Normal and Soft Flash Modes 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 Hard Flash Mode, the LED brightness is controlled by
the Enable pins. Those programming pins can be used
as simple enable pins, as PWM input, again offering
ample flexibility for setting the LED brightness.
2 Key Features
! _{High-Efficiency High-Power Charge Pump}
- 1:1, 1:1.5, and 1:2 Intelligent Adaptive Mode Set-
ting (IAMS)
- Efficiency up to 95%
- Soft Start to Reduce Inrush Current
- Low-Noise Constant-Frequency Operation
! _{Current Sinks}
- 400mA Continuous Flash Current (@VIN = 3.2 to
5V, VOUT = 5V)
- 480mA Maximum Pulsed Flash Current
- Programmable: 0 to 160mA, 0.625mA Resolution
! _{Flexible Brightness Control}
- Three 0 to 160mA LEDs
- Individually Addressable via I²C Interface
! _{Three Operating Modes}
- Normal Mode (I²C Interface)
- Soft Flash Mode (I²C Interface)
- Dedicated Control Pins for Hard Flash Modes
! _{Two General Purpose Inputs/Outputs}
- Digital Input, Output, and Tristate
- Programmable Pull-Up and Pull-Down
- Strobe Pin can be used for Camera Flash Control
! _{LED Disconnect in Shutdown}
! _{Open LED Detection}
! _{Low Stand-By Current (6µA), Interface Fully}
Operating
! _{Low Shut-Down Current (0.2µA)}
! _{Wide Battery Supply Range: 3.0 to 5.5V}
! _{Thermal Protection}
! _{24-Pin, Small Form-Factor QFN Package}
- 4 x 4 x 0.85mm, 0.5mm Pitch
- Enhanced Thermal Characteristics
3 Applications
Lighting management for cameras, mobile telephones,
PDAs, and other 1-cell Li+ or 3-cell NiMH powered
devices.
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