AL3644EV1 User Guide
AL3644EV1
Page 1 of 10
Aug 2019
www.diodes.com
General Description
The AL3644 is a dual LED flash driver that
provides a high level of adjustability within
a small solution size. The AL3644 utilizes a
2-MHz
or
4-MHz
fixed
frequency
synchronous boost converter to provide
power to the dual 1.5-A constant current
LED sources. The dual 128 level current
sources provide the flexibility to adjust the
current ratios between LED1 and LED2. An
adaptive regulation method ensures the
current sources remain in regulation and
maximizes efficiency.
Features of the AL3644 are controlled via an
I
2
C-compatible interface. These features
include: hardware flash and hardware torch
pins (STROBE and TORCH/TEMP), a TX
interrupt, and an NTC thermistor monitor.
The
device
offers
independently
programmable currents in each output leg
to drive the LEDs in a Flash or Movie Mode
(Torch) condition.
The 2-MHz or 4-MHz switching frequency
options, overvoltage protection (OVP), and
adjustable current limit allow for the use of
tiny, low-profile inductors and (10-µF)
ceramic capacitors. The device operates
over a –40°C to 85°C ambient temperature
range.
Applications
Camera Phone White LED Flash
Key Features
Dual Independent 1.5-A LED Current
Source Programmability
Accurate
and
Programmable
LED
Current Range from 1.4mA to 1.5A
Torch Currents up to 180mA per
Channel
Flash Timeout Values up to 400ms
Optimized Flash LED Current During Low
Battery Conditions (IVFM).
> 85% Efficiency in Torch Mode (at 100
mA) and Flash Mode (at 1A to 1.5A)
Grounded Cathode LED Operation for
Improved Thermal Management
Small Solution Size: < 16 mm2
Hardware Strobe Enable (STROBE)
Synchronization Input for RF Power
Amplifier Pulse Events (TX)
Hardware Torch Enable (TORCH/TEMP)
Remote NTC Monitoring (TORCH/TEMP)
400-kHz I2C-Compatible Interface
–
AL3644 (I2C Address = 0x63)
AL3644EV1 Specifications
Parameter
Value
Input Voltage
2.7V
DC
to 5.5V
DC
Number of LEDs
2 Channels,
1 LED per Channel
Maximum Torch
current / Channel
180mA
Maximum Flash
current / Channel
1.5A
XYZ Dimension
70mm x 36mm x 11mm