LM3643_15 Datasheet, PDF (23/39 Pages) Texas Instruments – Synchronous Boost Dual LED Flash Driver with 1.5-A High-Side Current Sources

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10 Applications and Implementation
LM3643, LM3643A
SNVS967A – AUGUST 2014 – REVISED NOVEMBER 2014
NOTE
Information in the following applications sections is not part of the TI component
specification, and TI does not warrant its accuracy or completeness. TI’s customers are
responsible for determining suitability of components for their purposes. Customers should
validate and test their design implementation to confirm system functionality.
10.1 Application Information
The LM3643 can drive two flash LEDs at currents up to 1.5 A per LED. The total LED current the LM3643 boost
can deliver is 1.5 A (I_LED1 + I_LED2 ). The 2-MHz/4-MHz DC/DC boost regulator allows for the use of small value
discrete external components.
10.2 Typical Application
L1
1 2H
V_IN
2.5V J 5.5V
C1
10 2F
2P/2C
LM3643
IN
SW
HWEN
SDA
OUT
C2
10 2F
SCL
STROBE
TORCH/
TEMP
TX
LED1
LED2
GND
D1
D2
Figure 36. LM3643 Typical Application
10.2.1 Design Requirements
Example requirements based on default register values:
DESIGN PARAMETER
Input Voltage Range
Brightness Control
LED Configuration
Boost Switching Frequency
Flash Brightness
EXAMPLE VALUE
2.5 V to 5.5 V
I²C Register
2 Parallel Flash LEDs
2 MHz (4 MHz selectable)
750 mA per LED
Copyright © 2014, Texas Instruments Incorporated
Product Folder Links: LM3643 LM3643A
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