LM3699 Datasheet, PDF (1/25 Pages) Texas Instruments – High-Efficiency White LED Driver

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LM3699
SNVS821A – JANUARY 2014 – REVISED MARCH 2014
LM3699 High-Efficiency White LED Driver
1 Features
•1 Drives Parallel High-Voltage LED Strings for
Display or Keypad Lighting
• Boost Converter up to 90% Efficiency
• Four User-Selectable Full-Scale Current Settings
(20.2 mA, 18.6 mA, 17.0 mA, 15.4 mA)
• Quick-Dimming Enable Terminal (ILOW)
• Simple PWM Duty Cycle Control
• 24-V Overvoltage Protection Threshold
• Fixed 1-MHz Switching Frequency
• Integrated 1-A/40-V MOSFET
• Three Current Sink Terminals
• Adaptive Boost Output to LED Voltages
• Thermal Shutdown Protection
• 29-mm² Total Solution Size
3 Description
The LM3699 is a three-string, high-efficiency, PWM-
controlled power source for display backlight or
keypad LEDs in smartphone handsets. The high-
voltage inductive boost converter with integrated 1-A,
40-V MOSFET provides the power for three series
LED strings. The boost output automatically adjusts
to LED forward voltage to minimize headroom voltage
and effectively improve LED efficiency.
The ILOW terminal provides a method to quickly
reduce LED brightness during camera flash
operation.
The LM3699 has integrated overvoltage, overcurrent,
and thermal protection.
The device operates over a 2.7-V to 5.5-V input
voltage range and a −40°C to 85°C temperature
range.
2 Applications
• Power Source for Smart Phone Illumination
• Display or Keypad Illumination
Device Information
ORDER NUMBER
PACKAGE
BODY SIZE
LM3699YFQ
DSBGA (12)
1,64 mm x 1,29 mm
Simplified Schematic
VIN
CIN
L
D1
VOUT up to 24V
COUT
ILOW
RST
PWM
IN
SW
OVP
IS1
IS0
ILOW
HWEN
PWM
LM3699
HVLED1
HVLED2
HVLED3
GND
Boost Efficiency vs V_IN with 10-µH Inductor
90%
88%
86%
84%
82%
80%
78%
76%
3s3p
74%
72%
70%
4s3p
5s3p
6s3p
2.5 3 3.5 4 4.5 5 5.5
VIN (V)
C012
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.