LM3550_13 Datasheet, PDF (1/37 Pages) Texas Instruments – 5A Flash LED Driver with Automatic VLED and ESR Detection for Mobile Camera Systems

LM3550
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SNVS569B – MAY 2009 – REVISED MAY 2013
LM3550 5A Flash LED Driver with Automatic V_LED and ESR Detection for Mobile Camera
Systems
Check for Samples: LM3550
FEATURES
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•2 Up to 5A Flash Current
• 4 Selectable Super-Capacitor Charge Voltage
Levels (4.5V, 5.0V, 5.3V, Optimized)
• Flash Optimized Charge Mode for Optimal
Efficiency
– 33% Faster Charge Time Using Optimal
Mode
– 49% Less Power Dissipated in Current
Source using Optimal Charge Mode
• Fast Super-Capacitor Charger with 500 mA
Input Current Limit
• Adjustable Torch Current (60 mA to 200 mA)
• Ambient Light or LED Thermal Sensing with
Current Scaleback
• End-of-Charge Output (EOC)
• Dedicated Indicator LED Current Source
• No Inductor Required
• Manual Flash Enable via Strobe Pin Input
• Programmable Flash Pulse Duration, and
Torch and Flash Currents via I²C-compatible
Interface
• True Shutdown (LED Disconnect)
• Flash Time-Out Protection
• LED Temperature Protection or Ambient Light
Sensing Pin
• Low Profile 20-Pin UQFN Package (3.0 mm ×
2.5 mm × 0.8 mm)
APPLICATIONS
• Camera Phones
• Digital Still Camera
• Voltage Rail Management
DESCRIPTION
LM3550 is a low-noise, switched-capacitor DC/DC
converter designed to operate as a current-limited
and adjustable (up to 5.3V) super-capacitor charger.
LM3550 features user-selectable super-capacitor
charge-termination voltages and an optimal charge-
termination mode that maximizes flash-energy
efficiency by accounting for flash element losses.
Additionally, the device provides one adjustable
constant current output (up to 200 mA) and one
NFET controller ideal for driving one or more high-
current LEDs either in a high-power flash mode or a
low-power torch mode.
Typical Application Circuit
C1
1 PF
C2
1 PF
2.7V to 5.5V
CIN
4.7 PF
C1+ C1- C2+ C2-
VIN
VOUT
LM3550
COUT
2.2 PF
VIO
NTC
SCL
SDA
EOC
STROBE
BAL
Super-
Capacitor
ALD/TEMP
IND
GND
LED-
FET_CON
FB
RSENSE
3 mm
4.2 mm
Current Source Super-Capacitor
Charger
C1 = C2 = 1 PF, CIN = 4.7 PF, COUT = 2.2 PF
10V X5R or X7R
Figure 1.
Figure 2. Solution Size
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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
2
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2009–2013, Texas Instruments Incorporated