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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
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
2
I
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
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
AL3644EV1
Aug 2019
www.diodes.com
fixed
frequency
independently
AL3644EV1 User Guide
Key Features
 Dual Independent 1.5-A LED Current
Source Programmability
 Accurate
and
Current Range from 1.4mA to 1.5A
 Torch Currents up to 180mA
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
2 Channels,
Number of LEDs
1 LED per Channel
Maximum Torch
180mA
current / Channel
Maximum Flash
1.5A
current / Channel
XYZ Dimension
70mm x 36mm x 11mm
Programmable
LED
per
to 5.5V
DC
DC
Page 1 of 10

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Summary of Contents for Diodes AL3644EV1

  • Page 1 AL3644EV1 User Guide General Description The AL3644 is a dual LED flash driver that Key Features provides a high level of adjustability within  Dual Independent 1.5-A LED Current a small solution size. The AL3644 utilizes a Source Programmability 2-MHz...
  • Page 2: Connection Instructions

    AL3644EV1 User Guide Figure 1. Top View Figure 2. Bottom View Connection Instructions USB docking board connection: Connect one end of the USB docking board to the PC using the supplied USB cable and the other end to J2 of the AL3644EVM using the supplied 10-pin ribbon cable.
  • Page 3 AL3644EV1 User Guide Evaluation Board Schematic Figure 3. Evaluation Board Schematic AL3644EV1 Page 3 of 10 Aug 2019 www.diodes.com...
  • Page 4: Evaluation Board Layout

    AL3644EV1 User Guide Evaluation Board Layout Figure 4. PCB Board Layout Top Layer Figure 5. PCB Board Layout Middle Layer 1 AL3644EV1 Page 4 of 10 Aug 2019 www.diodes.com...
  • Page 5 AL3644EV1 User Guide Evaluation Board Layout Figure 6. PCB Board Layout Middle Layer 2 Figure 7. PCB Board Layout Bottom Layer AL3644EV1 Page 5 of 10 Aug 2019 www.diodes.com...
  • Page 6: Bill Of Materials

    AL3644EV1 User Guide Bill of Materials Name Quantity Package Description U-WLB1713-12 AL3644 1uH, 2.5A, 0.063Ω D1, D2 LED, Ultra White C1,C2,C4 0402 CAP, CERM, 10uF, 6.3V, +/-20%, X5R CAP, CERM, 100uF, 6.3V, +/-20%, 1206 1206 RES, 0Ω, 5% R2,R3 0603 RES, 1.0kΩ, 5%...
  • Page 7 AL3644EV1 User Guide C-Compatible Interface Program and Operation Diodes Incorporated has created an I C-compatible program and USB docking board that can help exercise the part in a simple way. Contained in this document is a description of how to use the interface software.
  • Page 8: User Interface

    AL3644EV1 User Guide 1. User Interface The AL3644 GUI provides the user with access to all of the registers found on the device. Through a combination of buttons, drop-down boxes and sliders, the user can configure the AL3644 to perform in the desired mode. Please note that no data is written to the device until the Write button found within the corresponding register is pressed.
  • Page 9 AL3644EV1 User Guide 3. I/O Pin Controls The AL3644EVM provides the user with the capability to control the TORCH, STROBE and TX inputs without the need of an external supply. The Ext. Strobe Button toggles the Strobe pin high for the duration entered in the field next to the button.
  • Page 10 Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diodes Incorporated website, harmless against all damages.

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