MP1529 Datasheet, PDF (1/11 Pages) Monolithic Power Systems – Fixed Frequency Step-Up Converter LCD Backlight Plus Flash

TM
The Future of Analog IC Technology ^TM
DESCRIPTION
The MP1529 is a step-up converter plus 3
current sources for driving two 6-LED backlight
strings to 30mA and a 4-LED flash string to
150mA from a single Lithium-Ion battery.
The step-up converter generates an output
voltage as high as 25V from a 2.7V to 5.5V
input source. Three current sources drive in
three modes. In backlight mode two strings of 6
LEDs are lit with up to 30mA of current. In the
backlight plus preview mode the 4 flash LEDs
are lit with the preview current. In flash mode
the flash LEDs are lit with up to 150mA of
current and the two backlight strings are turned
off. There are three pins to independently set
the backlight, preview and flash current.
The MP1529 includes built-in open lamp over
voltage protection, cycle-by-cycle current limit,
over temperature shutdown, input under voltage
control and integrated soft-start.
The MP1529 is available in a tiny 16-pin 4mm x 4mm
package.
MP1529
Fixed Frequency Step-Up Converter
LCD Backlight Plus Flash
FEATURES
• 2.7V to 5.5V Input Voltage Range
• 25V Maximum Step-Up Voltage
• <1µA Shutdown Mode
• 1.2MHz Fixed Frequency Operation
• LCD Backlight to 30mA, Flash to 150mA
• Cycle-By-Cycle Current Limit
• Independent Backlight, Preview and Flash
Current Adjustment
• Special PWM Dimming
• Over Voltage Protection
• Under Voltage Lockout
• Integrated Soft-Start
• Thermal Shutdown
• Tiny 4mm x 4mm QFN Package
APPLICATIONS
• PDAs
• Cellular Phones
• Digital Still Cameras
• Digital Video Cameras
“MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic
Power Systems, Inc.
TYPICAL APPLICATION
V_IN
D1
EN1
EN2
C4
10nF
16 _IN
1 _EN1
SW ¹⁴
OUT ¹²
2
EN2
3 _COMP
4 _SS ^MP1529
9 _ISET1
LED1 ⁸
10 _ISET2
LED2 ⁷
11 _ISET3
LED3 ⁵
GND
6 _GND
PGND ^{13, 15}
V_OUT
MP1529_TAC_S01
Efficiency vs LED Current
(Backlight Mode, 2 Strings of 3 LEDs)
82
V_IN=4.2V
80
78
V_IN=3.6V
76
V_IN=2.7V
74
72
2 4 6 8 10 12 14 16 18 20
LED CURRENT (mA)
MP1529_EC01
MP1529 Rev. 1.0
www.MonolithicPower.com
1
11/23/2005
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© 2005 MPS. All Rights Reserved.