NCP5050 Datasheet, PDF (1/14 Pages) ON Semiconductor – 4.5 W Flash White LED Boost Driver

NCP5050
4.5 W Flash White LED
Boost Driver
The NCP5050 is a high powered fixed frequency PWM boost
converter optimized for constant current applications such as driving
high-powered white LEDs. This device has been designed with
high-efficiency for use in portable applications and is capable of
driving up to 5 high power LEDs in series for camera flash or
flashlight (torch) applications. To support the need of driving the
LEDs in a high current pulse mode for flash as well as a continuous
mode for focus or torch, a control pin and support circuitry is
incorporated which allows the user to program two LED currents. The
both output current are fully configurable via the use of 2 external
resistors and this average current can be reduced by applying a PWM
signal to the CTRL pin up to 50 kHz.
The PWM operates at 1.7 MHz which allows the use of small
inductors and ceramic capacitors. In addition the compensation is
internal to the device which simplifies the design and reduces the PCB
component count. To protect the device cycle-by-cycle current
limiting and a thermal shutdown circuit have been incorporated as
well as output over-voltage and time out protection. The maximum
peak current level of the power switch is adjustable to allow further
system optimization. The NCP5050 is housed in a low profile space
efficient 3x3 mm thermally enhanced WDFN.
Features
•ăHigh Efficiency Up to 88% for 2 LED (V_F = 3.5 V by LED) at 200 mA
•ăHigh frequency Dimming PWM Control
•ăMaximum V_out of 20 V
•ă1.7 MHz PWM DC/DC Converter
•ăShut Down Control Facility with True-Cutoff
•ăOpen LED (Output Overvoltage) Protection
•ă1.2 s Timer out Function
•ăSoft Start to Limit Inrush Current
•ăSmall 3x3x0.8 mm WDFN Package
•ăThese are Pb-Free Devices
Typical Applications
•ăWhite LED Flash (Camera Phone, Digital Still Camera,
Personal Media Player)
•ăPortable Flash Lights
•ăMedium Size LCD Backlight (See Application Note AND8294/D for
Details)
2.7 to 5.5 V
C1
4.7 mF
9
PVIN
L1
2.2 mH
10
SW
D1
D2
C2
1 mF
R1
2.8 k
ENABLE
FLASH/
TORCH
5
PCA
2
VS
3
4 ^CTRL
HCM
7
FB
NCP5050
2.0 ^R2
R_HCS
R3
R_LCS ^10.0
L1: TDK VLF5012T-2R2
D6 ^{D1: ON MBR130LSF}
C1: 4.7 mF 6.3 V 0603
TDK C1608X5R0J475M
C2: 1 mF 25V 0805
TDK C2012X5R1E105M
Figure 1. Typical Application Circuit
http://onsemi.com
MARKING
DIAGRAM
WDFN10, 3x3, 0.5P
CASE 522AA-01
ISSUE A
5050
ALYWG
G
A
= Assembly Location
L
= Wafer Lot
Y
= Year
W
= Work Week
G
= Pb-Free Package
(Note: Microdot may be in either location)
PIN CONNECTIONS
PGND 1
VS 2
CTRL ₃
CM ₄
PCA ₅
10 SW
9 PVIN
8 LCS
7 FB
6 HCS
(Top View)
ORDERING INFORMATION
See detailed ordering and shipping information in the package
dimensions section on page 13 of this data sheet.
©Ă Semiconductor Components Industries, LLC, 2007
1
October, 2007 - Rev. 0
Publication Order Number:
NCP5050/D