XC9116 Series
Step up DC/DC Converter - Backlight LED Driver
Preliminary
April 14, 2004 V4
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Suitable for White LED Backlight Driver Applications
Four White LEDs can be driven in series
Can be configured to drive two parallel legs
with 3 LEDs per leg
Illumination control by 10kHz PWM signal
Input Voltage Range
Output Voltage
Oscillation Frequency
High Efficiency
Lx Overvoltage Limit
Ultra Small Packages
2.5V ~ 6.0V
17.5V (MAX.)
1.0MHz
88%
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APPLICATIONS
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For White LED Drivers
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Mobile phones, PHS
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PDAs
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Digital still cameras
XC9116B type (Under development)
SOT-25, USP-6B
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GENERAL DESCRIPTION
The XC9116 series is a fixed frequency, constant current step-up
DC/DC converter ideal for driving LEDs used in backlighting
applications on cellular phones, PDAs and digital cameras etc.
Output voltage of up to 17.5V can be derived, and from a 3.2V
input four white LED's can be driven in series or alternatively, using
a 2.5V input, a network of two parallel legs with three in each may
be driven.
Luminance of the LED's is controlled by changing the duty cycle of
a PWM
signal applied to the CE pin. Efficiency is high with the XC9116
through the high 1MHz switching frequency and the low feedback
reference voltage, ensuring the RLED losses are minimal.
In addition, an internal MOSFET with an Rds-on of 2Ω is used. A
low profile and small board area solution can be achieved using a
chip coil and an ultra small ceramic output capacitor (CL) of
0.22µF.
The 'B' type of XC9116 (under development) has an additional fault
detection circuit. If the LEDs are disconnected or damaged in such
a way that prevents feedback, excess or run away output voltage is
prevented by stopping the drive to the internal MOSFET.
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FEATURES
Input Voltage Range
Output Voltage Range
: 2.5V ~ 6.0V
: Up to 17.5V externally set-up
Reference voltage 0.2V±5.0%
Oscillation Frequency
ON Resistance
Efficiency
: 1.0MHz
±20%
: 2.0Ω
: 88%
(When driving 3 white LEDs in series :
VIN=3.6V, ILED = 20mA)
Control
Stand-by Current
Load Capacitor
Lx Limit Current
Lx Overvoltage Limit
No Lx Overvoltage Limit
: PWM control
: ISTB=1.0µA (MAX.)
: 0.22µF, ceramic
: 300mA
: XC9116B series (under development)
: XC9116D series
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TYPICAL APPLICATION CIRCUIT
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TYPICAL PERFORMANCE CHARACTERISTICS
L:22uF
VLF3010A
VIN
2.5V~6.0V
SD
XB0ASB03A1B
100
90
80
CIN
1uF
LED:NSPW310BS x 3
SD:XB0ASB03A1B, CL:TMK316J224KF
L:CDRH3D16
EFFICIENCY (%)
VIN
Lx
CL
0.22uF
70
60
50
40
30
20
10
0
0
VLF3010A
CBC2518
CE
100Hz to
10kHz
VSS
FB
R
LED
10ohm
20mA
VIN=3.0V
5
10
15
20
25
30
LED CURRENT (mA)
Semiconductor Ltd.
Data Sheet
1
TOREX [ TOREX SEMICONDUCTOR ]
